Prac Modr Hair Scie Ch3

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Shampoo and

Conditioner ScienceRobert Y. LochheadUniversity of Southern Mississippi

Shampoos and conditioners are the highest volume o products

sold in personal care. In this chapter, we will consider the science

that underpins the unctioning o these product types. Te principal

unction o shampoos is to cleanse the hair. However, since theintroduction o two-in-one shampoos in the 1970s, it has not

been sufficient or a shampoo to merely cleanse the hair. Modern

shampoos should at least cleanse, condition, make the hair easier

to style, and ragrance the hair with a pleasant, lingering smell.

Modern conditioners should lower the riction between hair fibers to

allow easier grooming and alignment o the hair fibers while leaving

them glossy and avoiding lankness.Te science o shampoos and conditioners is still evolving and

in addition to describing undamentals, this chapter attempts

to take the reader to the rontiers o research in shampoo and

conditioner science.

Introduction

Located within the hair ollicle is a sebaceous gland thatcontinuously excretes an oily material, known as sebum, onto

the hair and scalp. Tis substance consists o compounds such as

atty acids, hydrocarbons, and triglycerides, and serves as natures

conditioning treatmentproviding lubrication and surace

Practical Modern Hair Science

www.Alluredbooks.comCHAPTER 3


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Shampoo and Conditioner Science

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hydrophobicity, while potentially replenishing components o

the cell membrane complex. However, aer a day or so, buildup

o this substance begins to result in a greasy look and eel.

Moreover, particulate dust and dirt adhere readily to this sebum

layer. In modern cultures such sebum-soiled hair is deemed to

be undesirable, and thereore, it should be removed on a regular

basis by a acile process. Tis process is, o course, shampooing.

Sebum cannot be removed by water because oil and water do not

mix. Aqueous shampoos can remove oily soil rom the hair surace

because shampoos contain surace-active agents, commonlyabbreviated as surfactants.Te molecules o these surace-active

agents sel-assemble into micelles, which are the agents that

solubilize oily soils.

o understand how suractants work, it is necessary to consider

the exact process that leads to oil and water being incompatible.

Tere are two different possibilities or substances to be insoluble

in water. In one case, substances have stronger intermolecularcohesion than water. Tis is why substances like sand, clay, and

glass are insoluble in water; the molecules o sand attract each

other more strongly than the molecules o water and this attraction

leads to the sand being insoluble. Tis reason or the insolubility is

exactly opposite to the reasons or the insolubility o hydrophobic

substances such as oils. Te intermolecular orces between the oil

molecules are weaker than the intermolecular bonds between watermolecules and the oils are expelledrom water. Tis expulsion arises

largely rom entropy and the effect has been coined hydrophobic

interaction.1,2From the time o the Phoenicians, it has been known

that oil spreads to calm troubled waters. Tis effect arises rom the

act that the spread oil has a lower surace tension than the water. At

this point it is appropriate to consider the effect known as surace

tension. Molecules in the bulk o liquids are attracted on all sides

by their neighboring molecules. However, molecules at the surace

are subjected to imbalanced orces because they are attracted by the

underlying liquid molecules, but there is essentially no interaction

with the vapor/gas molecules on the other side o the liquid/vapor


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Chapter 3

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boundary. Tis imbalance leads to a two-dimensional orce at the

surace, namely surace tension. Te surace tension is numerically

equal to the surace ree energy.3Te magnitude o surace tension

directly correlates with the strength o the intermolecular orces.

Water has hydrogen bonds, dipole-dipole interaction, and dispersion

orces between its molecules, and as a consequence the surace

tension o water is rather high72 mN/meter at room temperature.

On the other hand, only dispersion orces are present between the

molecules o alkanes. As a consequence, the surace tension o

alkanes is relatively lowranging 2030 mN/meter.Suractants comprise molecules that contain two parts: a

hydrophobic segment that is expelled by water and a hydrophilic

segment that interacts strongly with water. Such molecules are said

to be amphipathic(amphi meaning dual andpathic rom the

same root aspathoswhich can be interpreted as suffering). Tus,

a suractant molecule suffers both oil and water. Tis dual nature

coners interesting properties on suractants in aqueous solution.At very low concentrations, the suractant is expelled to the surace,

a process called adsorption. Tis adsorption causes the suractant

concentration at the surace to be much higher than the suractant

concentration in the bulk o the solution. At extremely low

concentrations, when the suractant molecules on the surace are

located too ar apart to effectively interact with each other, raubes

Rule applies. raubes Rule states that the ratio o the suraceconcentration to the bulk concentration increases threeold or each

CH2group o an alkyl chain.4Tis ratio is called the surace excess

concentration.5According to this rule, soap with a dodecyl chain

should have a surace excess concentration that is more than a hal-

million times its concentration in the bulk solution. At extremely

low concentrations, the suractant molecules on the surace act as a

two-dimensional gas. As the concentration increases, the suractant

molecules begin to interact, but they are still mobile within the

plane; they behave as two-dimensional liquids. At even higher

concentrations, as the suractant saturates the surace, the chains

orient out o the surace plane and the chain-chain interactions


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cause the suractant to behave as a two-dimensional solid. Irving

Langmuir was awarded the 1932 Nobel Prize in Chemistry or

measuring this effect and explaining it on a molecular basis.6

When a suractant adsorbs to saturate an aqueous surace, the

surace is largely composed o the suractants hydrophobic groups;

this means that the surace essentially has low surace energy. As a

consequence o the low surace energy, the surace area is easier to

expand to a film. Tis means that the system is easier to oam, since

aqueous oams really consist o water films with entrapped gas. I

the oam surace is structured by the adsorbed suractant, then oamstability can be achieved.7

Surfactant Micelles

Relatively large aggregates orm within solution just beyond

the concentration at which the surace becomes saturated with

suractant.8Tese aggregates are surfactant micelles in which

the hydrophobes are segregated within the core o the aggregateand the hydrophilic groups are located on the surace where they

interact strongly with water.9For a given system, micelles initially

orm at the precise concentration at which the driving orce or

surace adsorption becomes equal to the driving orce or aggregate

ormation. Tis driving orce is the chemical potential o the

suractant species. Te lowest concentration at which micelles orm

is named the critical micelle concentration(CMC). Te aggregates arelarge; or example, micelles o sodium dodecyl sulate at the CMC

contain about 100 molecules and the thickness o the head group

layer is about 0.4 nm.10

Suractant micelles have liquid centers. Tey effectively solubilize

hydrophobic substances only when the temperature o the system is

above the Kraf point. Kraf ound this phenomenon in 1895, and

68 years later Shinoda explained that the Kraf point corresponds to

the melting point o the hydrated solid suractant.11

Micelles have different shapes. Te simplest shape is the

spherical micelle that was postulated by Hartley in 1936. Te

shape o a micelle can be explained on the basis o the principle


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Chapter 3

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o opposing orces (see Figure 1). wo or three amphipathic

molecules alone cannot orm a stable micelle because micellization

is essentially a cooperative process that requires the participation

o many amphipathic molecules bound together by hydrophobic

interaction. However, i hydrophobic interaction accounted solely

or the ormation o micelles, then the association would continue

until phase separation occurred, as in oil separating rom water.

Tereore, there must be a orce that opposes the hydrophobic

association and controls the size o the micelles. Tis orce is the

repulsion between the head groups that could arise rom ion-ionrepulsion and/or hydration o the head groups.12Teoretically,

the repulsive surace terms are difficult to handle rom a

thermodynamic perspective but the presence o micelles has been

validated experimentally.

I micelle structure was determined solely by thermodynamics,

spherical micelles would always be avored over other shapes.

However, real micelles are not restricted to a spherical shape;

spherical structures account or only a small minority o micelles.

Te shapes o suractant molecules and the way they can be packed

Figure 1.The shape of a surfactant micelle is determined by

the balance between the mutual repulsion between hydrophilic

groups at the micelle surface and the cohesion due to hydrophobic

interaction. This has been dubbed the principle of opposing forces.


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also plays an important role in determining micelle shape. Although

thermodynamics and packing geometries are inextricably linked,

by considering the limits o possible packing arrangements we can

obtain insight into the shapes o micelles and the transormation

rom one shape to another as physical and chemical conditions

are changed. In this context, the many shapes o micelles, arising

rom the principle o opposing orces, can be appreciated by

considering Packing Factor Teory (Figure 2).13First, consider a

spherical micelle. In this instance the micelle radius, R, the volume

o the hydrophobic core, v, and the surace area o the amphipathicmolecule at the hydrophobe/water interace, a, are related by:

Eq. 1

Te radius o a micelle, R,cannot exceed the ully extended

length, l, o the hydrophobe chain o the suractant molecule. Tis

gives the critical condition or the ormation o spherical micelles:

Eq. 2

Figure 2.The packing factor of a surfactant molecule is the volume of

the tail group divided by the volume of the cylinder subtended by the

head group to the length of the tail group.


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Te raction, v/al, is known as the packing actor (Figure 3).

When the packing actor has a value o 1/3, the suractant molecule

can be approximated by a conical shape and the molecules pack into

a sphere (Figure 4).

When the packing actor has a value o , the micelles become

cylinders (Figure 5), and when the packing actor has a value o

1, the suractant molecules pack as planar bilayers in a so-called

lamellar structure (Figure 6).

For ionic suractants, the area per head group can be decreased

by adding soluble salt to the solution to lessen the ionic repulsion

between the head groups. (Salt also enhances the hydrophobic

interaction.14) Increase in salt and/or suractant concentration causes

spherical micelles to transition to rods and then to long worm-like

micelles.15Te wormlike micelles behave like polymers in solution.16

Figure 3.Surfactant molecules with a packing factor of 1/3 have a

shape that can be approximated by a cone.

Figure 4.These conical molecules pack naturally into a sphere.


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Tese micelles also orm branched as well as linear structures, and

above a certain concentration (the critical overlap concentration, C*)

they entangle just like polymer molecules17and display viscoelastic

rheology.18-20Tis behavior is depicted in Figure 7as it was

explained by Candau in 1993.21An increase in salt concentration

causes spherical or elliptical micelles to transition into rods, then

to worms then to branched worms. As the suractant concentration

increases, the micelles orm entangled networks. Consumers desire

Figure 5.Surfactant molecules with a packing factor

of pack naturally into cylinders.

Figure 6.Surfactant molecules with a packing factor of 1 pack

naturally into bilayer planes.


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thicker shampoos, in part because they are easier to apply, but

also or aesthetic reasons; a thicker ormula is generally perceived

as being more-luxurious. Te desired rheology is achieved rom

ormulations that contain worm-like micelles.

Wormlike micelles do, however, show non-polymeric behavior

at certain shear rates when the shear stress becomes independent o

the shear rate and the relaxation time becomes monodisperse.22Tis

behavior has been explained on the basis that the entanglements

can be broken and reormed as the rod-like micelles disassemble

and then reassemble upon passing through each other.23-24Systemslike these have been dubbed phantom networks by Cates to

signiy that one micelle flows through another just as we imagine a

phantom would pass through a wall. Te phantom network behavior

may explain why shampoos can show viscoelasticity without the

stringiness observed in entangled polymer solutions.

At higher concentrations, the rod-like micelles mutually repel,

and this avors alignment into a nematic phase. At still higher

concentrations the aligned rods pack in a hexagonal array to orm

hexagonal phase liquid crystals (Figure 8). Te hexagonal phase

has the properties o a clear ringing gel that is bireringent in

polarized light.

Figure 7.Ionic surfactant micelles change shape as a function of ionicstrength and surfactant concentration.


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As the suractant concentration is increased urther and/or

dissolved salt concentration is increased, the surace o the micelles

becomes less curved until the large planar aggregates o the lamellar

phase are ormed (Figure 9). Modern shampoos consist essentially

o entangled worm-like micelles and conditioners are usually in the

orm o the lamellar phase.

In summary, shampoo and conditioner ormulation essentially

involves the preparation o suractant mixtures that possess the

Figure 8.Rod-like micelles can pack into hexagonal liquid crystal phase.

Figure 9.Increase in surfactant concentration causes micelles to transition from

spheres to rods to hexagonal phase to lamellar phase to inverse hexagonal

phase to inverse micelles.


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aorementioned structures, while also being esthetically pleasing.

Te hair care ormulation scientist has an ever-increasing variety

o suractants available in the ormulation toolbox, and so these

structures can be obtained via a wide range o concoctions.

Nonetheless, attaining such stable structures is not a trivial task,

due to the presence and interactions o so many ingredients in

the typical ormulation. Tereore, with historical knowledge

involving many established ingredients already being relatively

well-understood, it is a brave ormulation chemist that opts to cut a

new pathway. Moreover, it is also probably prudent to arrive at thesestructures in the most cost-effective manner. For these reasons, it

is imperative to understand how the suractant structure, together

with interactions with other molecules alters the nature o the

aggregate structures.

Oily Soil Removal Mechanisms

Te principal unction o a shampoo is to remove oily soil romthe hair. Tere are several principal detergency mechanisms or

removing oily soils: roll-up,25emulsification, penetration, and

solubilization.

In the roll-up mechanism, the detergent solution causes a steady

increase in the contact angle o the oil at the oil/fiber/aqueous

interace (Figure 10).

Te oil droplet is rolled up on the surace, and when the contact

angle reaches 180degrees, the interacial orce that is holding it to

the surace is overcome by the wetting tension o the oil and aqueous

solutions on the fiber surace. Roll-up is avored by fibers that are

Figure 10. In this mechanism the oil contact angle at the oil/water/fiber interface

steadily increases until it rolls up and floats off of the solid surface. This

mechanism was first reported by N. K. Adams.


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oleophobic and hydrophilic.26Te removal o oily soil by detergent

compositions is not necessarily predictable due to the wide variation

o the surace properties o hair that arise rom prior treatments

and weathering. Moreover, the transport o the detergent solution

to the fiber surace can occur by three different routes: (i) along the

fiber surace, (ii) through a previously applied permeable surace

treatment, or (iii) through the body o the fibers (Figure 11).

Roll-up o oily drops on fibers occurs when the contact angle

exceeds a critical value and this causes the oily drop to adopt an

unstable axially asymmetric attachment on one side o the fiber.27

Te rate o roll up depends also on the viscosity o the oily soil,

and mechanical action is oen necessary to dislodge viscous oily

soils rom the fiber surace. In some cases, the oil orms a viscous

emulsion when contacted by the detergent composition, and theresulting viscous soil can be difficult to remove rom the fiber.

Perect hair is covered by a covalently attached monolayer o

18-methyleicanosoic acid (18-MEA), which coners hydrophobicity

on the hair. Modern grooming techniques and weathering removes

this layer o 18-MEA.28Removal o the layer o 18-MEA results

in hair becoming macroscopically hydrophilic.29Te roll-up

mechanism, thereore, should be expected to become more

prominent on damaged rather than pristine hair.

Initially i the fiber is completely coated in oil, or i the fiber itsel

is hydrophobic, the detersive solution cannot easily reach the oil/fiber

interace, and the soil will be removed by emulsification (Figure 12).

Figure 11. In the roll-up mechanism, the detergent solution can be transported

to the fiber/oil interface along the fiber surface, through a permeable coating

on the fiber, or through the fiber itself.


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Emulsification is avored by low oil/water interacial tension that

allows the oil surace to be expanded into an emulsion droplet.30

In the penetration mechanism o oily soil removal, suractant-

rich phases penetrate the oil at the interace. Tis results in an

interacial liquid crystalline phase that swells and is broken off

to reveal a resh soil interace, and then the process is repeated

again and again.31Te penetration mechanism occurs with polar

soils and/or phase separated coacervates o nonionic suractants

above the lower critical solution temperature (LCS). Spontaneousemulsification, in the absence o detersive suractant, has been

observed or non-polar-polar soil mixtures like sebum.32Te

penetration mechanism can occur with anionic suractants that

orm coacervate phases in the presence o calcium salts.33

Solubilization is the process o incorporating a water-insoluble

hydrophobic substance in the internal hydrophobic core o micelles.

Direct solubilization can occur in the presence o an excess osuractant micelles with respect to oily soil.34Te rate o exchange

o suractant molecules between micelles is important because the

micelles must re-assemble around the soil to solubilize the soil by

encompassing it inside the micelle.

Foam/Lather

One essential attribute o a shampoo is its ability to produce

a rich lather or oam. Te important elements o a oam are

the lamellae and the Plateau border. Te micrograph in Figure

13depicts these structural eatures o a oam. Te lamellae are

stabilized by suractants adsorbed at the air-water interace.

Figure 12. Emulsification can remove the soil if the interfacial tension between the

oily soil and the surfactant solution is low.


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Foams lose stability by two main mechanisms: draining o the

liquid and puncture o the lamellae. Te oam lamellae are the

junctions between two oam bubble cells and the plateau border issituated at the triple-cell junction. Te Laplace pressure in the liquid

components o the oam is inversely proportional to the curvature

o the interace. Te higher curvature o the plateau border results

in a lower pressure in that region and this causes the liquid in the

oam to drain preerentially rom the lamellae to the plateau borders.

Based upon this reasoning, it can be understood that drainage can

be hindered in two ways, namely by blockage o the lamellae or byblockage at the plateau border. About two decades ago, Des Goddard

careully measured the drainage rom oam films and deduced

that polyquaternium-24 adsorbed across the lamellar interace and

hindered the drainage o liquid rom the oam. In addition, about

thirty years ago, Stig Friberg concluded that certain liquid crystals

blocked the plateau border region and delayed oam drainage and

conerred longer-term stability on suractant oams. In the case o

cationic polymers, hindered drainage o the lamellar liquid could be

caused by adsorption o the cationic entities at the lamellar surace

with the nonionic and/or anionic blocks in the lamellar liquid.

Figure 13. Micrograph showing surfactant foam structure.


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Alternatively, ormation o phase-separated coacervates between the

cationic polymer and the anionic suractant could result in blockage

o the plateau border. O course, i the interaction o the cationic

polymer was strong enough to orm inverse micellar structures,

then there would be a possibility that the phase-separated particles

could cause a local reversal o the curvature in the lamellae and this

in turn would result in breakage o the lamellar film and subsequent

oam destabilization. Tis type o oam destabilization mechanism

has been extensively reported by Peter Garrett.

Solid Foams

Cationic conditioners

that would normally be

incompatible with liquid

shampoos can be delivered

rom solid oams. Solid

oams also make it possibleto have one scent or the

solid and then to allow

a different ragrance to

bloom when the solid is

wetted by water.35Te

porous solids are made by

mixing the suractants,glycerin as a plasticizer,

and water in the presence

o a water-soluble polymer.

Figure 14shows a solid

oam in which poly(vinyl

alcohol) is the water-soluble

polymer. Aer a heating

and mixing cycle, the

porous solid is ormed by

aeration.

Figure 14. Micrograph showing solid foam structure

(reproduced from US Patent Application 20110195098).


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The Anatomy of a Shampoo Formulation

Shampoos consist essentially o water, a primary suractant,

one or more co-suractants, and soluble salt. Other ingredients

are added or ragrance, preservation, conditioning, and styling

attributes. Cleaning is achieved mainly by the primary suractant,

which is oen an anionic suractant that would adopt a conical

shape i it was present in water alone. Te co-suractant is usually

a nonionic or zwitterionic suractant with a relatively small head

group surace area. Tis molecular shape allows the co-suractant

to serve two roles: (i) it packs between the molecules o the primarysuractant to reduce the curvature and to promote the ormation

o worm-like micelles with their high viscosity and luxurious

rheology; and (ii) it packs between the primary suractant in the

lamellae o the oam to provide good lather that is easily removed

by rinsing. Salt enhances the unction o the co-suractant by

damping down the ionic repulsion between primary suractant

head groups and promoting the ormation o wormlike micelles. Iexcess salt or co-suractant is added, shampoo compositions can

separate into phases that contain co-existing micelles and liquid

crystals. Tese phase-separated compositions oen exhibit thin

viscosities and haziness.

The Primary Surfactant

Te lauryl sulates have been the primary suractant workhorses

o the shampoo industry or decades. Te sulate head groups bear

an anionic charge when dissolved in water. Te long chain alkyl

tail group has an average length o 12 carbon atoms. It is important

to understand that this is an average chain length; commercial

lauryl sulates have a distribution o chain length rom as short as

8 carbons to as long as 18 carbons. Tis chain length distribution

changes rom supplier to supplier and it also changes depending

on the source o raw materials. Formulators should be aware that

changes in the chain length distribution o the suractants can lead

to subtle changes in the properties o the shampoo.


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During the 1970s, triethanolamine lauryl sulate was preerred

as a primary suractant due to its excellent cleaning properties and

luxurious flash oaming capability. However, it was replaced by

laureth sulates or two reasons: the concern over the ormation o

nitrosamines rom secondary amine components and the reduced

eye irritation exhibited by the laureth sulates.

Over the last two decades, the primary suractants o most

shampoos have been sodium laureth sulate, ammonium lauryl

sulate, and sodium lauryl sulate.

Te co-suractantoen called the oam boosterhas mostprominently been selected rom two types o materials: alkylamide

MEA and alkylamidobetaines. Modern shampoos contain primarily

betaines as co-suractants.

Enhancing Mildness

Isethionates are suractants noted or their mildness to skin,

and or at least three decades, they have been the basis o non-soapdetergent bars such as Dove (Unilever). Tey have been making

inroads into shampoos based upon mildness claims. Moreover,

Unilever researchers discovered that the mildness can be enhanced

even urther by including mildness benefit agents that can be

flocculated by cationic polymers present in the ormulation and

delivered as flocs upon dilution o the ormulation.36Te preerred

benefit agent in this case is petrolatum; the cationic polymersare well known polymers like polyquaternium-10 and guar

hydroxypropyltrimonium chloride. Tis could orm the basis o

shampoos that are mild to the skin.

Certain non-cross-linked linear acrylic copolymers can lower

the irritation potential o suractants and provide products that are

clear and highly oaming.37Te preerred polymers interact with the

suractant and effectively shiing the CMC to higher concentrations,

while lowering the critical aggregation concentrationthe latter

being the concentration at which the suractant selectively interacts

with the polymer rather than adsorbing at the liquid surace

(Figure 15). It is postulated that ree suractant molecules and


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ree suractant micelles are responsible or irritation o skin and

eyes and that binding o the suractant to the polymer effectively

reduces the concentration o ree micelles. A measure o mildness

is the delta CMC, which is defined as the difference between the

CMC o the suractant alone and the higher CMC o the suractant

in the presence o the polymer. Larger values o delta CMC or a

particular suractant are apparently correlated with lowering o the

irritation potential. Te delta CMC provides a measure that is useul

or selecting, comparing, and optimizing polymers that reduce the

irritation potential o selected suractant systems. Carbomer andacrylates copolymer have been identified as polymers that exhibit a

satisactory delta CMC.

Conditioning Shampoos

odays conditioning shampoos are expected to coner wet-hair

attributes o hair soness and ease o wet-combing, and the dry hair

attributes o good cleansing efficacy, long-lasting moisturized eel,

and manageability with no greasy eel.

Te origin o conditioning shampoos can be traced to the

balsam shampoos o the 1960s ollowed by the introduction o

polyquaternium-10 by Des Goddard38,39 in the 1970s and 1980s in

which he introduced the concept o polymer-suractant complex

coacervates that phase-separate and deposit on the hair during

Figure 15. Plot of surface tension vs. surfactant concentration for

surfactant alone and for surfactant in the presence of polymer. The

difference in the CMC induced by the presence of the polymer is

claimed to be related to the effect of the polymer in enhancing themildness of a shampoo.


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rinsing. Te first two-in-one shampoos depended on a complex

coacervate being ormed between anionic suractant and the

cationic hydroxyethylcellulose, polyquaternium-10. Tis complex

was solubilized in excess suractant and it phase-separated as a

coacervate liquid phase upon dilution during the rinsing cycle.

Later guarhydroxypropyltrimonium chloride was introduced as

an alternative cationic polymer that worked on the same principle

as polyquaternium-10. Tese two polymer types continue to

dominate the compositions o conditioning shampoos.40Guar is a

galactomannan and it is interesting that, in recent years, recentlya new cationic galactomannan hydrocolloid, cationic cassia,

has been claimed to coner conditioning shampoo benefits.41,42

Polygalactomannans consist o a polymannan backbone with

galactose side groups. In guar gum, there is a pendant galactose

side group or every two mannan backbone units. Tese galactose

groups sterically hinder the substitutable C-6 hydroxyl unit,

limiting the extent o possible cationic substitution on guar gum.In cassia, however, there is less steric hindrance o the C-6 hydroxyl

group and, consequently, higher degrees o cationic substitution

are possible with cassia (60% or cassia relative to 30% or guar).

Cationic cassia can be used as a conditioning polymer in shampoos

and conditioners to impart cleansing, wet-detangling, dry-

detangling, and manageability.

Te mechanism o conditioning shampoos depends upon theormation o polymer/suractant coacervates that phase-separate

during rinsing (Figure 16). Polyions in aqueous solution are

surrounded by an electrical double-layer o counterions, and the

location o the counterions with respect to the polyion is determined

by a balance between chemical potential and electrochemical

potential, called the Donnan Equilibrium. Suractant ions contain a

large hydrophobic group that makes them intrinsically less soluble

in water than inorganic ions such as chloride or bromide. When

suractant ions interact with an oppositely charged polyion, they

bind strongly and displace the water-soluble inorganic ions rom

the polyion; that is, they ion-exchange. Once the suractant ions


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bind, hydrophobic interaction between the hydrophobic suractant

tails causes the polymer-suractant complex to phase separate at

concentrations below the suractant critical micelle concentration.

Above the CMC, the suractant concentration is sufficiently high

to orm micelles or hemi-micelles along the polyion chain, and the

polyion/suractant complex is solubilized. Conditioning shampoos

are ormulated within the range o suractant concentrations that

correspond to this solubilized regime. When these shampoos are

diluted to a concentration that is in the vicinity o the CMC, then thecomplex coacervate phase-separates. Te separated phase is deposited

on the hair during rinsing, and it can co-deposit other additives such

as silicone conditioning agents or anti-dandruff agents. Maximum

coacervate deposition occurs at precise ratios o cationic polymer to

anionic suractant, but the optimum ratio or coacervation might not

coincide with the best ratios or cleaning and oaming.

Cationic guar has been a known additive or 2-in-1 shampoos

or more than three decades. However, it has now been shown that

improved post-shampoo detangling times are achieved by including

a small degree o hydrophobic substitution in the cationic guar

derivatives.43

Figure 16. A schematic phase diagram that explains the mechanism of coacervate

formation in 2-in-1 shampoos.


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Chapter 3

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Synthetic copolymers o acrylamide and a riquat monomer are

postulated to provide improved deposition on hair and improved

conditioning perormance with respect to wet combing.44

Silicones have become standard ingredients in many conditioning

shampoos or the smooth, silky hair eel that they coner. Silicones

were introduced to shampoos as 2-in-1 conditioning agents in

the 1980s. Te introduction o silicones needed to overcome two

substantial deficiencies: (i) silicones are well known deoamers, and

(ii) silicones are incompatible with typical shampoo compositions

and they tend to separate due to their low specific gravity. Initialattempts to stably suspend the silicone included the use o water

miscible saccharides such as corn syrup.45Later products comprised

xanthan gum in the shampoo as a suspending agent and acceptable

oaming attributes were conerred on the shampoos by ormulating

with relatively high levels o alkyl sulates as the primary suractant,

cocamide MEA as the co-suractant, and ethylene glycol distearate

as a suractant structuring agent.46In the actual application, thereis a technical contradiction involved in the deposition o silicone

conditioning components rom a detersive, cleansing system;

the detersive system is designed to remove oil, grease, dirt, and

particulate material rom the hair, and the conditioning agent

has to be deposited on that same hair in one process. As a result,

large excess amounts o silicone are used to ensure deposition,

and one consequence o this is that large amounts o the expensiveconditioning silicone can be rinsed away rather than deposited on

the hair. Cationic polymer/anionic suractant coacervates enhance

the deposition o silicones on hair and, consequently, increase the

efficiency o conditioning shampoos.47,48

Volatile cyclic siloxanes coner the desired silky initial eel, but

these materials are difficult to ormulate in consistent homogenous

ormulations, Tey tend to spread uncontrollably over the hair and

skin.49Tis effect can be controlled with polymeric silicone gels

ormed in volatile silicones to provide both the initial silky eel and a

high viscosity and smooth eel when dry.50Branched molecules with

a silicone core and hydrocarbon branches, or networks ormed rom


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96

these branched units, have been disclosed as suitable or improving

sensory eel, while minimizing phase separation and conerring

good shampoo removability.51

Shampoos containing more than one cationic conditioning

polymer and a quaternary silicone give more uniorm deposition on

hair than standard shampoos based on polyquaternium-10 as the

sole conditioning polymer. Tus, a conditioning polymer cocktail

comprising poly(acrylamide-co-acrylamidopropyltrimonium)

chloride, guar hydroxypropyltrimonium chloride, and silicone

quaternium-13 give uniorm deposition on hair. In this instance, theclaims are based upon multiple testing and analysis:52

A multiple attribute consumer assessment study that measured

the attributes o cleanliness, wet-comb, dry-comb, hair soness,

lather amount, and creaminess.

Secondary Ion Mass spectrometry to detect silicon on the hair

surace. Tis method revealed that a standard commercial

shampoo concentrated silicone on the cuticle edges o the hair,whereas the patent application shampoo distributed silicone

more evenly.

X-ray photoelectron spectroscopy (XPS) to measure the thickness

o the silicone polymer layer on hair rom Si:C:O ratios. Tis

method revealed that the commercial shampoo deposited

a significant amount o silicone, and the patent application

shampoo deposited only one or two molecular layers.

Instron ring compression as a measure of combability.

Complex coacervates can also be ormed rom mixtures o

cationic and anionic polymers. Tis could be the underlying

mechanism in shampoos that include an anionic and cationic

polymer that provide sleekness and gloss.53

wo drawbacks o silicones are that they oen destabilize oamand the final compositions are hazy due to light scattered rom

the suspended silicone droplets. Initially, silicone copolyols were

introduced to overcome the insolubility o silicones in shampoo

compositions, but this drastically reduced the amount o silicone


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Chapter 3

97

deposited onto hair and compromised conditioning perormance.

Clear, silicone-containing conditioning shampoos have been

ormulated by adding trideceth-2 carboxamide MEA to reduce the

silicone droplet size.54ransparent conditioning shampoos can be

ormulated by incorporating the silicone as microemulsified droplets,

but the small microemulsion droplets tend to be rinsed away rather

than deposited during the shampooing process. Moreover, coalescence

o the droplets can lead to loss o transparency in the product during

storage. Attempts have been made to overcome these challenges by

including silicone emulsions with high internal viscosities, typicallygreater than 100,000 centistokes, but the high internal phase viscosity

gives deposited silicone that is can be difficult to remove and this

causes buildup with each consecutive shampooing. Such buildup

usually reduces the volume o the desired hair style and causes

droop and flatness. Fortunately, shampoo compositions providing

superior conditioning to hair while also providing excellent storage

stability and optionally high optical transparency or translucency canbe obtained by combining low viscosity microemulsified silicone oil

with cationic cellulose polymers and cationic guar polymers having

molecular weights o at least about 800,000 and charge densities

o at least about 0.1 meq/g.55Conditioning shampoo ormulations

that include a silicone microemulsion in a conditioning shampoo

containing guar hydroxypropyltrimonium chloride and an anionic

detersive suractant have also been reported to be clear.56,57I pre-gelatinized starch, such as hydroxypropyl distarch phosphate, is

included with polyquaternium-10, transparent conditioning shampoos

can be obtained.58

Another way to minimize buildup is to treat the hair with water-

in-water emulsions that can be prepared by including cationic

polymers with soluble salts in suractant compositions.59Tese water-

in-water emulsions provide conditioning benefits with good spread

o the conditioning phase on the hair and less chance o buildup.

Te living ree radical polymerization techniques that have

emerged in the last decade offer the prospect o preparing precise

polymers with unprecedented accuracy in molecular structure and


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98

variety o chemical types.60Tis technique has enabled synthesis o

a wide diversity o block and gra polymers that were previously

unattainable. Such polymers offer the prospect o conerring

conflicting properties within one molecule, which in turn can lead

to improved compatibilities in the same system while maintaining

stability. Tese conflicting properties could possibly be achieved

by blending different polymers, but different polymers do not mix

readily at the molecular level and phase separation may result.61

Block, gra, and gradient copolymers serve to compatibilize such

compositions and gradient polymers have been proposed or thispurpose. Block copolymers comprising polycationic blocks and

nonionic blocks or surace deposition62and or improved oam

retention63have been claimed, which are desired to deposit on

hair in order to modiy the chemical properties o the surace

or protection or compatibility; to modiy hairs hydrophobic or

hydrophilic surace properties; or to modiy eel or mechanical

properties o the substrate rom two-in-one products. Te polymersdisclosed are block copolymers o polyMAEAMS (methylsulate

[2-(acryloyloxy)ethyl]-trimethylammonium) g/mole) and

polyacrylamide.

Conditioning shampoos can also be ormulated to unction

by mechanisms other than cationic polymer-induced complex

coacervation, such as:

Conditioning can be achieved by including chain extended

silicones in an anionic suractant-based shampoo. Specific

examples o useul silicones include silicone emulsions

containing divinyldimethicone/dimethicone copolymer.64

Shampoos containing polyalkylene oxide alkyl ether particles

givelarger coacervate cohesive flocs (20500 microns) that

resist shear and coner superior deposition efficiency on hair orgood wet conditioning.65

Conditioning shampoos containing a polyester formed from

adipic acid and pentaerythritol provides conditioning or dry

hair (possibly rom reduced hair riction), with no greasy eel.66


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Chapter 3

99

Inclusion of polybutene is thought to increase the deposition

o silicone conditioners and provide improved conditioning

benefits, such as wet and dry eel and combing.

O Lenick disclosed a unique class o alkyl polyglucoside quaternary

suractants possessing all the multiunctional attributes o cleansing,

conditioning, and sel-preserving.67Tis could have the potential o

greatly simpliying the ormulation o multiunctional shampoos.

A conditioning shampoo that contains a conditioning gel

phase in the orm o vesicles is described by Unilever researchers.68

Cationic conditioners are usually incompatible with anionicshampoos, and consequently conditioners based upon cationic

suractants are usually applied as separate post-shampoo products.

Te Unilever researchers prepared a conditioning gel phase by

combining a small amount o water, atty alcohol, a long-chain

secondary anionic suractant (sodium cetostearyl sulate), and

a long-chain cationic suractant (behenyltrimethylammonium

chloride), and subjecting the mixture to high shear to orm a stablevesicular gel phase. Prolonged shear causes the lamellar gel phase to

roll-up into an array o multilamellar vesicles (Figure 17). Te gel

phase was added to a dilute primary suractant solution (sodium

laureth sulate) to orm a conditioning shampoo that conerred good

wet smoothness on hair.

Deposition of Particles on Hair to Confer Styling Benefits

Whereas conditioning shampoos are ormulated to reduce hair

inter-fiber riction, some consumers need an increase in riction in

Figure 17. Lamellar gel subjected to high shear rolls up into vesicles of gel phase that can

be used for conditioning. (Figure reproduced from US Patent Application 20110243870).


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100

order to achieve styling benefits. Factors that influence hair body

and ullness include hair diameter, hair fiber-to-fiber interactions,

natural configuration (kinky, straight, wavy), bending stiffness,

hair density, and hair length. Increases in riction can be achieved

by depositing particles such as titanium dioxide, clay, pearlescent

mica, or silica on the hair surace. Particles can be deposited or

more purposes than merely increasing inter-fiber riction, e.g., or

conerring color, or slip (spherical particles are best or this), and

or conditioning (hollow silica, hollow polymer particles). Hollow

particles can be included in shampoo to increase hair volume.69,70

Deposited hollow particles that can increase fiber-fiber interaction

include complexes o gas-encapsulated microspheres (such as silica

modified ethylene/methacrylate copolymer microspheres and

talc-modified ethylene/methacrylate copolymer microspheres);

polyesters; and inorganic hollow particles.

It has already been noted that cationic guar enhances

the deposition o conditioning agents. In a like manner, thismacromolecule enhances the deposition o particles on hair.71

Silicones and particulates can be deposited simultaneously. Tus,

enhanced deposition o particulate actives, such as zinc pyrithione

(shown on cadaver skin treated in a Franz diffusion cell), has

been reported72rom shampoos comprising a water-soluble

silicone (such as silicone quaternium-13, cetyltriethylammonium

dimethicone copolyol phthalate, or stearalkonium dimethiconecopolyol phthalate), a cationic conditioning agent (such as

acrylamidopropyltrimonium chloride/acrylamide copolymer, or

guar hydroxypropyltrimonium chloride), a cleansing detergent,

and suspending agents (such as carbomer, hydroxyethylcellulose,

and PVM/MA decadiene cross-polymer) to insure homogeneous

distribution o the insoluble active.

Hydrophobic modification o cationic hydroxyethylcelluloseis claimed to endow better efficacy. Tus, polyquaternium-24,

a hydrophobically modified cationic hydroxyethylcellulose, is

also disclosed as being a preerable thickener or zinc-depositing

compositions.73


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Chapter 3

101

It has been discovered that responsive particles, with two

contrasting polymers adsorbed to the particle core,74can adsorb

to the hydrophilic hair surace and render it hydrophobic, thereby

conerring conditioning attributes to the hair. For example, graing

o aminopropyl-terminated dimethicone and polyethylenimine

on titanium dioxide particles produces responsive particles.

Tese particles orm stable dispersions in water and aqueous

solutions because they are sterically stabilized by expansion o

the polyethylenimine into the aqueous medium. However, when

they are deposited on hair and dried, the polyethylenimine layercollapses and the dimethicone layer expands to render the surace

hydrophobic. Te useulness o these responsive particles is

demonstrated by including them in typical conditioning shampoo

and conditioner ormulations. In the case o the shampoo, inclusion

o the responsive particles results in a higher water contact angle on

the treated hair and the conditioner with particles causes an increase

in the hydrophobicity o the hair. On the other hand, shampooscontaining ethoxylated alcohols have been ound to enhance the

deposition o large particle silicones (52000 microns), and in this

case it is claimed that cationic polymer is not required.75

Two-phase Systems for Visual Attributes:

Tere is esthetic appeal to products that exist as separate phases

in the bottle but which mix during application to provide addedbenefit, such as moisturizing or conditioning, by interaction o the

components o the two phases. Te most obvious way to ormulate

such products is to use the immiscibility o water and oil in

ormulations that are shaken prior to use to produce a metastable

emulsion. However, when a suractant is included in the system such

a visually attractive phase separation can be mixed into an emulsion

due to shear in manuacturing and packing operations. Tere are

known de-emulsifiers, which are widely used in the oil industry,

but these demulsifiers also tend be deoamers that compromise the

lather o shampoos. Neutralized polyacrylate can be added as a non-

emulsiying oam stabilizer to yield phase-separated compositions


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102

that resist the production difficulties to make phase-separated

shampoos that orm temporary emulsions upon shaking and oam

during use.76 A two-phase shampoo system can also be ormed by

mixing polar lipophilic shampoo components with non-polar lotion

constituents such as mineral oil.77

Under appropriate conditions, phase-separated systems can be

prepared rom polymer solutions or micellar suractant solutions. I

two distinct aqueous phases are desired in a composition, one must

take into consideration the thermodynamics o coexisting phases

and the driving orce or such phase separation that comes directly

rom the chemical thermodynamics o the system. Tis is especially

the case or systems that contain polymers or micelles because the

configurational entropy is reduced as molecules are assembled

into polymers or aggregated into micelles, and mixing can become

unavorable. I the ree energy o mixing is insufficient to maintain

uniorm dispersion, spontaneous phase separation will occur.

Phase separation becomes more likely as the micellar aggregates orpolymers get bigger. Te addition o salts to ionic suractant micellar

systems causes a reduction in the suractant intra-micellar head-

group interaction, and oen an increase in hydrophobic interaction.

Tis can cause a pronounced increase in micelle size and consequent

phase separation into a suractant-rich phase and a suractant-poor

phase. Tis approach has been adopted by adding mineral salt to

induce two distinct layers,78

and by adding the detergent builder,sodium hexametaphosphate, to cause phase separation. In this case,

a thickener is required and the system comprises a suractant, a

thickener, a polyalkylene glycol, and a non-chelating mineral salt.

Te system spontaneously separates into two layers.

A multiphase composition comprising suractant, betaines,

co-suractant (such as an alkyl ether carboxylate, an acylglutamate;

or an acylisethionate), and an appropriate concentration o saltorms a stable multiphase system that becomes temporarily

uniormly dispensed upon agitation.79

Multiphase cleansing products have been introduced that go

beyond mere phase separation insoar as the separate phases can be


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Chapter 3

103

arranged to orm visually attractive patterns inside a transparent

container.80Te phases comprise an aqueous cleansing phase, a

benefit phase, and a non-lathering structured phase. Te aqueous

cleansing phase must be capable o adequate lathering.81Te

benefit phase comprises hydrophobic component(s) or conditioning

components. Tese products are designed at the nanoscale: the

structured phase can be a lamellar-phase ormed by adding sufficient

electrolytes to an appropriate suractant. Structurants such as

starch have been used in personal cleansing ormulations,82but the

suractant itsel can be structured. Tus, lamellar phase does exhibit

a yield stress that is sufficient to stably suspend the benefit phase.

However, the yield stress o lamellar phase can vary dramatically

with temperature, and, in order to overcome this problem, the

cleansing and benefit phases were density matched by adding

microsphere particles to reduce the specific gravity o the cleansing

phase or high density particles to the benefit phase to increase its

specific gravity. In this context, it is interesting that it has beenrecently disclosed that controlled phase separation and deposition

could conceivably be achieved by loading the desired active phase

into hollow-sphere polymer carriers,83and again it has been reported

that certain cationic guar derivatives can enhance the deposition o

conditioning additives and/or solid particle benefit agents.84

Lamellar phase, especially i it is made rom unneutralized long-

chain atty acids, usually displays poor dispersion kinetics and alather that is slow to build up or slow to rinse off. However, it has

surprisingly been discovered that swollen lamellar gels can exhibit

both high product viscosity and ast dispersion kinetics i they are

ormed by combining C16-24 normal monoalkylsulosuccinates

with n-alkyl atty acids o approximately the same chain length.85In

this context, Guth claimed a composition that was low-irritating to

skin and eyes but synergistic in oaming by combining zwitterionicsuractants-atty acid complexes with sulosuccinates,86and Pratley

reported synergistic oaming and mildness rom compositions

with combinations o specific long-chain suractants with specific

short-chain suractants and these included atty acids and


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104

alkylsulosuccinnates.87Amine-oxide copolymers have also been

claimed as suds-enhancers.88

Concentrated Cleansing Compositions

Most personal care products are based on aqueous compositions

but concentrated cleansing/personal care compositions offer

the benefits o lower transportation costs, less packaging, and

convenience or air travelers. I these products are solid, they

must possess sufficient strength to resist the orces o extrusion

during manuacture, shipping, and handling, but should disperserapidly in water during use. Porous solid particles that are

strengthened by hydrophilic polymers such as poly(vinyl alcohol)

or hydroxylpropylmethylcellulose have been shown to exhibit the

desired properties.89Control o interconnectivity o the porous

network is vital to this application and is described by a star volume,

a structure model index, or a percent open cell content.

Conditioners

Conditioning o damaged hair is commonly achieved by

treatment with aqueous ormulations that contain atty alcohols,

cationic suractants, and (optionally) silicones. Tese components

are considered to adsorb in a hydrophilic head-down, hydrophobic

tail-up conormation that coners hydrophobicity on the damaged

hydrophilic hair surace. Te role o a conditioner is to coner sleek

lubricity and gloss on the hair. Conditioners are usually based

upon cationic suractants, and they most oen are in the orm

o emulsions o multi-lamellar vesicles. Conditioners comprise a

primary cationic suractant, a co-suractant, and dissolved salt.

Conventional conditioner ormulations are based upon lamellar

gels or emulsions using either ceto-stearyl trimethylammoniumchloride or distearyldimethylammonium chloride as cationic

suractants and ceto-stearyl alcohol as co-suractant.

As a primary suractant, the vast majority o conventional

conditioners contain either cetyl/stearyl trimethylammonium


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Chapter 3

105

chloride or distearyldimethylammonium chloride. Te secondary

suractant is most oen ceto-stearyl alcohol.

Cetyl/stearyl trimethylammonium chloride is a conical molecule

according to Ninhams packing actor. On the other hand, ceto-

stearyl alcohol consists o molecules with the approximate shape

o an inverted conical molecule. Te role o ceto-stearyl alcohol

in a conditioner is to pack between the cationic cones and convert

the micellar structure into a lamellar structure with just enough

curvature to orm a vesicle. Distearyldimethylammonium chloride

spontaneously orms vesicles in the presence o salt, and thereore

there is usually no need to add a long-chain alcohol to conditioner

ormulations based upon distearyldimonium chloride.

Tese products orm a gel matrix that coners conditioning

benefits rom rinse-off products. Tey have been the basis o hair

conditioners or the last hal-century, and they provide excellent

detangling, wet- and dry-combing, and good anti-static properties,

but they can leave the hair eeing lank and greasy, and they give along-lasting slippery eel during rinsing which is perceived by some

consumers as an unclean hair eel.

Pristine hair, as it emerges rom the scalp, is coated with a

covalently bound layer o 18-methyleicanosoic acid (18-MEA).90-92

It has been shown that the layer o 18MEA coners hydrophobicity

and boundary lubrication on hair fibers.93Tis discovery has

influenced researchers to seek to include 18-MEA in conditionerormulations.94Pristine hair shows a measured advancing water

contact angle that is high, but a receding contact angle that is

likewise high, and the hair tends to align. However, once the

18-MEA layer is removed, the receding contact angle is low (even

approaching 0degrees), and this corresponds to cuticle edges that

are essentially hydrophilic. Tis means that the major differences

or such 18-MEA deficient hair would be in its drying behaviorrather than its wetting characteristics. Te low receding contact

angle would tend to pin the water to the hair. Tis would

lead to longer drying times during which the capillary orces

imparted by the water between hair fibers would tend to cause


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106

the hair fibers to clump and entangle. Te inclusion o 18-MEA

in prototype conditioner ormulations that were based upon

stearoxypropylmethylamine, dimethylaminopropylstearamide, and

stearyltrimethylammonium chloride le the conditioner on the

hair surace, and this in turn yielded improvements in inter-fiber

lubricity due to improved deposition at the hair surace.

Conditioning Polymers in Hair Straightening Applications

Te two main processes or relaxing or straightening hair are

hair treatment with a reducing agent to cleave the disulphide cystinebridges (SS) within the hair structure, and treatment o stretched

hair with a strong alkaline agent.

Repeated relaxation treatments can cause significant hair damage,

to both the cuticles and the cortex. Te damage can be assessed by

measuring the porosity o the hair, and the porosity o the keratin

fibers can be measured by fixing 2-nitro-para-phenylenediamine

at 0.25% in an ethanol/buffer mixture (10:90 volume ratio) at pH10 at 37C or 2 minutes. Cationic and amphoteric polymers, such

as polyquaternium-6, polyquaternium-7, and polyquaternium-39,

added to hair relaxer ormulations, mitigate this degradation o the

hair structure. Also, the inclusion o high molecular-weight (>106

g/mole) copolymers o acrylamide and diallyldimethylammonium

chloride, acryloyloxytrimethylammoniumchloride, or

acryloyloxyethyldimethylbenzylammonium chloride in the relaxingormula results in significant reduction in the hair structural

damage caused by alkaline relaxation.

Conditioning Polymers

Cationic conditioning polymers are used to enhance the

conditioning properties, especially to mitigate the effects o extreme

processing that are experienced during hair-straightening. Cationic

polymeric conditioners can improve wet combability and ameliorate

electrostatic charging o the hair (maniested by flyaway).

Many cationic polymers have been developed or the purpose

o conerring conditioning properties on hair. In act, there are


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Chapter 3

107

now more than one hundred polyquaternium ingredients listed in

the INCI dictionary, and this list is still expanding. Te primary

purpose o polyquaternium polymers is to coner good conditioning

benefits. A non-exhaustive list o conditioning polymers is shown in

Table 1.

Table 1. Examples of cationic conditioning polymers

Chitosan

Cocodimonium Hydroxypropyl Hydrolyzed Collagen

Cocodimonium Hydroxypropyl Hydrolyzed Hair Keratin

Cocodimonium Hydroxypropyl Hydrolyzed Keratin

Cocodimonium Hydroxypropyl Hydrolyzed Wheat Protein

Cocodimonium Hydroxypropyl Oxyethyl Cellulose

Steardimonium Hydroxyethyl Cellulose

Stearyldimonium Hydroxypropyl Hydrolyzed Oxyethyl Cellulose

Guar Hydroxypropyltrimonium Chloride

Starch Hydroxypropyltrimonium Chloride

Lauryldimonium Hydroxypropyl Hydrolyzed Collagen

Lauryldimonium Hydroxypropyl Hydrolyzed Wheat Protein

Stearyldimonium Hydroxypropyl Hydrolyzed Wheat Protein

Polyquaternium-4

Polyquaternium-10

Cationic hydroxyethylcellulosePolyquaternium-24

Hydrophobically modified cationic hydroxyethylcellulose

Poly(methacryloxyethyltrimethylammonium methosulfate)

Poly(N-methylvinylpyridinium chloride)

Onamer M (Polyquaternium-1), PEI-1500 (Poly(ethylenimine)

Polyquaternium-2

Polyquaternium-5-poly(acrylamide-methacryloxyethyltrimethylammoniumethosulfate)]

Polyquaternium-6 poly(dimethyldiallylammonium chloride)

Polyquaternium-7

poly(acrylamide-co-dimethyldiallylammonium chloride)


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108

Polyquaternium-8

Polyquaternium-11

[poly-(N-vinyl-2-pyrrolidone-methacryloxyethyltrimethylammonium ethosulfate)]

Polyquaternium-16 [Co(vinyl pyrrolidone-vinyl methylimidazolinium chloride)

Polyquaternium-17

Polyquaternium-18

Polyquaternium-22

Poly(sodium acrylate dimethyldiallyl ammonium chloride)

Polyquaternium-27

Polyquaternium-28

Polyvinylpyrolidone-methacrylamidopropyltrimethylammonium chloride)

Polyquaternium-31

Poly(N,N-dimethylaminopropylacrylate-N-acrylamidine-acrylamide-

acrylamidine-acrylic acid-acrylonitrile) ethosulfate

Polyquaternium-39

Poly(dimethyldiallylammonium chloridesodium acrylateacrylamide)

Polyquaternium-43

Poly(acrylamide-acrylamidopropyltrimoniumchloride-2-acrylamidopropyl

sulfonate-DMAPA)

Polyquaternium-44

Poly (vinyl pyrrolidone--imidazolinium methosulfate)

Polyquaternium-46

Poly (vinylcaprolactam-vinylpyrrolidone-imidazolinium methosulfate)

Polyquaternium-47Poly (acrylic acid-methacrylamidopropyltrimethyl ammonium chloridemethyl

acrylate)

Polyquaternium-53

Polyquaternium-55

Poly(vinylpyrrolidone-dimethylaminopropylmethacrylamide-lauryldimethylpropy

lmethacrylamido ammonium chloride)

PVP/Dimethylaminoethyl Methacrylate Copolymer

VP/DMAPA Acrylate Copolymer

PVP/Dimethylaminoethylmethacrylate Polycarbamyl

Polyglycol Ester

Table 1. Examples of Cationic Conditioning Polymers (Cont.)


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Chapter 3

109

PVP/Dimethiconylacrylate/Polycarbamyl Polyglycol Ester

Quaternium-80 (Diquaternary polydimethylsiloxane)

Poly(vinylpyrrolidone--dimethylamidopropylmethacrylamide)

VP/Vinyl Caprolactam/DMAPA Acrylates Copolymer

Amodimethicone

PEG-7 Amodimethicone

Trimethylsiloxyamodimethicone

Ionenes

Poly(adipic acid-dimethylaminohydroxypropyldiethylenetriamine)

Poly (adipic acid-epoxypropyldiethylenetriamine) (Delsette 101)

Silicone Quaternium-8

Silicone Quaternium-12

Polyampholytes have been commercially available asconditioning polymers or a considerable time. A prominent

example is polyquaternium-39, which is a copolymer o

diallyldimethylammonium chloride, acrylamide, and acrylic acid.

When this is polymerized in a single batch process, the mismatch

in reactivity ratios between these monomers results in a lack o

compositional uniormity. An improved version o this type o

terpolymer o diallyldimethylammonium chloride, acrylamide, andacrylic acid has been made by a monomer eed method or better

control o molecular weight and composition.95

Copolymers comprising a diallylamine (typically diallyldimethyl

ammonium chloride) and vinyllactam monomers (typically

polyvinylpyrrolidone) are useul film-ormers that coner

conditioning properties such as good wet and dry combability, eel,

volume, and handleability.96

Silicone Conditioners

Silicone quaternaries have long been known as hair conditioning

compounds.

Table 1. Examples of Cationic Conditioning Polymers (Cont.)


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110

A recent patent application rom Evonik Goldschmidt is

directed to silicone quats that coner conditioning with longer

lasting conditioning through several shampoo cycles. Te premise

is that long-term substantivity to hair requires the conditioning

agent to contain a string o cationic charges. Tis was achieved

by Goldschmidt by polymerizing cationic monomers and

graing them to silicone backbones. In general, water-soluble

monomers polymerized in the presence o silicones yield a

mixture o water-soluble polymers and unsubstituted silicones

because the two ingredients are incompatible and attachmento the polymer chain to the silicone would require appropriate

coupling groups. Te Evonik researchers rose to the challenge

by polymerizing the cationic monomers in the presence o

silicone polyethers. Te ether groups are compatible with the

quat monomers, and they readily chain transer to give gra

copolymers. Once graed, the copolymers are quaternized to

coner permanent positive charges with enhanced substantivityto hair. Te gras are obtained by polymerizing the readily

available monomers, dimethylaminoethylmethacrylate, or

3-trimethylammoniopropyl-methacrylamide.

Leave-on silicone conditioners specifically targeted to non-

shampoo applications coner enhanced and relatively durable

conditioning. Tese contain emulsified vinyl-terminated silicones

applied in combination with a conventional cationic conditioner. Apreerred product type is a mousse. Tese silicone block copolymers

can achieve excellent conditioning at relatively high viscosities (100

KPa/s-1).

Improved conditioning that coners surprisingly reduced riction

on hair can be achieved by including an aminosilicone in which the

aminosilicone has a airly large range o average particle sizes rom

about 550 microns.97

References

1. C Tanford, The Hydrophobic Effect: Formation of Micelles and Biological Membranes,

Ch 1, Wiley Interscience: New Jersey (1980).


37/42

Chapter 3

111

2. HS Frank and MW Evans, Free volume and entropy in condensed systems: iii. Entropy

in binary liquid mixtures; partial molal entropy in dilute solutions; structure and

thermodynamics in aqueous electrolytes,J Chem Phys, 13, 507-533 (1945).

3. JT Davies and EK Rideal, Interfacial Phenomena, Ch 1, Academic Press: Waltham, MA,

(1961).4. J Traube, Ueber die Capillarittsconstanten organischer Stoffe in wsserigen Lsungen,

Justus Liebigs Annalen der Chemie, 265, 27-55 (1891).

5. JW Gibbs, The Collected Works of J. Willard Gibbs, Longmans: New York (1928).

6. I Langmuir, The constitution and fundamental properties of solids and liquids, II. Liquids,

J Amer Chem Soc,39, 1848-1906 (1917).

7. KJ Mysels, Soap Films: Studies of their thinning, Pergamon Press: Oxford (1959).

8. JW McBain, Colloidal electrolytes: Soap solutions and their constitution,J Amer Chem

Soc, 42, 426-460 (1920).

9. GS Hartley,Aqueous Solutions of Paraffin-chain Salts, Hermann & Cie: Paris (1936).

10. C Tanford, The Hydrophobic Effect: Formation of Micelles and Biological Membranes,pp 85, Wiley Interscience: New Jersey (1980).

11. K Shinoda, N Yamaguchi, A Carlsson, Physical Meaning of the Krafft Point: Observation

of Melting Phenomenon of Hydrated Solid Surfactant at the Krafft Point,J Phys Chem,

93, 7216-7218 (1989).

12. C Tanford, The Hydrophobic Effect: Formation of Micelles and Biological Membranes,

pp 57, Wiley Interscience: New Jersey (1980).

13. JN Israelachvili, DJ Mitchell and BW Ninham, Theory of self-assembly of hydrocarbon

amphiphiles into micelles and bilayers, Faraday Trans. 2,J Chem Soc, 72, 1525-1568

(1976).

14. MG Cacace, EM Landau, JJ Ramsden, The Hofmeister series: salt and solvent effects oninterfacial phenomena, Quart Rev Biophys, 30, 241-177 (1997).

15. S Candau, A Khatory, F Lequeux, F Kern, Rheological behaviour of wormlike micelles:

Effect of salt content,Journal de Physique IV,03, C1, 197-209 (1993).

16. JF Berret, J Appell, G Porte; Linear rheology of entangled wormlike micelles, Langmuir,

9 (11), 28512854 (1993).

17. E Buhler, JP Munch and SJ Candau, Dynamical properties of wormlike micelles: A light

scattering study,JPhys II France,5, 765-787 (1995).

18. H Rehage and H Hoffmann, Rheological properties of viscoelastic surfactant systems,

J Phys Chem, 92,47124719 (1988).

19. H Hoffmann, Viscoelastic surfactant solutions, in: Structure and Flow in SurfactantSolutions, CA Herb and RK Prudhomme, eds, ACS Symposium Series 578, American

Chemical Society (1994).

20. PA Hassan, SJ Candau, F Kern, and C Manohar, Rheology of wormlike micelles with

varying hydrophobicity of the counterion, Langmuir, 14,60256029 (1998).

21. F Lequeux and S J Candau, Dynamical properties of wormlike micelles, in: Structure

and Flow in Sur factant Solutions, CA Herb and RK Prudhomme, eds, ACS Symposium

Series 578, American Chemical Society (1994).

22. JF Berret, Transient rheology of wormlike micelles, Langmuir, 13, 22272234 (1997).

23. NA Spenley, ME Cates, and TCB McLeish, Nonlinear rheology of wormlike micelles, Phys

Rev Lett71, 939942 (1993).

24. ME Cates, Theoretical modeling of viscoelastic phases, Structure and Flow in Surfactant

Solutions, CA Herb and RK Prudhomme, eds, ACS Symposium Series 578, American

Chemical Society (1994).

25. NK Adam,J Soc Dyers Colour, 53, 122 (1937).

26. E Kissa, Wetting and detergency, Pure & Appl. Chem, 53, 2255-2268 (1981).

27. BJ Carroll, Equilibrium conformations of liquid drops on thin cylinders under forces of

capillarity. A theory for the roll-up process.


38/42


112

28. R Molina, F Comelles, MR Julia, P Erra, Chemical modifications of human hair studied by

means of contact angle determination.

29. V Dupres, D Langevin, P Guenon, A Checco, G Luengo, and F Leroy, Wetting and

electrical properties of the human hair surface: Delipidation observed at the nanoscale,

J Colloid Inter face Sci,306, 34-40 (2007).30. CA Miller and KH Ramey, Solubilization-emulsification mechanisms of detergency,

Colloids and Surfaces A, Physicochemical and Engineering Aspects.74, 169-215 (1993).

31. ASC Lawrence, The mechanism of detergence, Nature, 183, 1491 (1959).

32. DG Stevenson, Surface Activity and Detergency, K Durham, ed., MacMillan: London

(1961).

33. CA Miller and KH Ramey, Solubilization-emulsification mechanisms of detergency,

Colloids and Surfaces A, Physicochemical and Engineering Aspects.74, 169-215 (1993).

34. BJ Carroll, The kinetics of solubilization of nonpolar oils by nonionic surfactant solutions,

J Colloid Inter face Sci, 79, 126-135 (1981).

35. JR Glenn et al, Porous, Dissolvable Solid Substrate and Surface Resident CoatingComprising Water Sensitive Actives, US Patent Application 20110195098, Aug 11, 2011;

US Patent Application 20110189247, Aug 4, 2011; US Patent Application 20110189246,

Aug 4, 2011; US Patent Application 20110182956, July 28, 2011.

36. LS Tsaur et al, Personal Wash Cleanser Comprising Defined Alkanoyl Compounds,

Defined Fatty Acyl Isethionate Surfactant Product and Skin or Hair Benefit Agent

Delivered in Flocs Upon Dilution, US Patent Application 20110245125, Oct 6, 2011,

assignee CONOPCO, INC., D/B/A UNILEVER.

37. JJ Librizzi et al, Low-irritation compositions and methods of making the same, US Patent

Application 20100311628, Dec 9, 2010, assignee Johnson & Johnson.

38. ED Goddard, Polymersurfactant interaction: Part II Polymer and surfactant of opposite

charge, in: Interactions of Surfactants with Polymers and Proteins, ED Goddard and

KP Ananthapadmanabhan, eds, CRC Press (1993).

39. ED Goddard, Polymer/surfactant interaction in applied systems, in: Principles of Polymer

Science and Technology in Cosmetics and Personal Care, ED Goddard and JV Gruber,

eds, Marcel Dekker (1999).

40. P. Brand, et al, Cleansing formulations comprising non-cellulosic polysaccharide with

mixed cationic substituents, US Patent 8,076,279, Dec 13, 2011, assigned to Hercules

Inc.

41. F. Utz, et al, Cationic cassia derivatives and applications therefore, US Patent 7,439,214,

Oct 21, 2008, assigned to Lubrizol Advanced Materials, Inc.

42. CA Lepilleur, Cationic cassia derivatives and applications therefore, US Patent 7,704,934,

April 27, 2010; US Patent 7,923,422, April 12, 2011, assigned to Lubrizol Advanced

Materials, Inc.

43. E Baldaro, et al, Home And Personal Care Compositions, US Patent Application

20110189248, Aug 4, 2011.

44. MM Peffly, et al, Personal care compositions containing cationic synthetic copolymer

and a detersive surfactant, US Patent Application 20070207109, Sep6, 2007, assigned to

The Procter & Gamble Company.

45. M. Pader, Shampoo compositions comprising saccharides, US Patent 4,364,837,

Dec 21, 1982, assigned to Lever Brothers Company.

46. RE Bolich, Jr., and TB Williams, Shampoo compositions containing nonvolatile siliconeand xanthan gum, US Patent 4,788,006, Nov 29, 1988, assigned to the Procter &

Gamble Company.

47. J Parran, Detergent compositions containing particle deposition enhancing agents,

US Patent 3,761,418, Sept 25, 1973, assigned to the Procter & Gamble Company.

48. MJ Fair, et al, Bars comprising benefit agent and cationic polymer, US Patent 6,057,275,

May 2, 2000, assigned to Unilever Home and Personal Care USA.


39/42

Chapter 3

113

49. MJ O Brien, Cosmetic compositions using polyether siloxane copolymer network

compositions, US Patent Application, 2005/0197477, Sept 8, 2005, assigned to

GEAM- Silicones.

50. TN Biggs and GE LeGrow, Lightly cross-linked poly(n-alkylmethylsiloxanes) and methods

of producing same, US Patent 5,493,041, Feb 20 1996, assigned to Dow CorningCorporation.

51. J. A. Kilgour, et al, Branched organosilicone compound, US Patent Application

2005/0165198, July 28, 2005, assigned to GE Plastics.

52. SM Niemiec, et al, Novel detergent compositions with enhanced depositing, conditioning

and softness capabilities, US Patent Application 2003/0176303, Sept 18, 2003.

53. M Maubru, Cosmetic composition comprising at least one anionic surfactant, at least

one cationic polymer and at least one amphiphilic, branched block acrylic copolymer

and method for treating hair using such a composition, US Patent 7,498,022, March 3,

2009, assigned to LOreal S.A.

54. H Denzer, et al, Transparent aqueous compositions comprising hydrophobic silicone oils,

US Patent 6,803,050, Oct 12, 2004, assigned to Kao Chemicals Europe S.L.

55. MM Peffly and JE Hilvert, Conditioning shampoo compositions, US Patent Application

20050158266, July 21, 2005, assigned to The Procter & Gamble Company.

56. MM Peffly, et al, Clear personal care compositions containing a cationic conditioning

polymer and an anionic surfactant, US Patent Application 20040234483, Nov 25, 2004,

assigned to The Procter & Gamble Company.

57. MM Peffly, et al, Clear personal care compositions containing a cationic conditioning

polymer and an anionic surfactant, US Patent Application 20040234484, Nov 25, 2004,

assigned to The Procter & Gamble Company.

58. H Albrecht, et al, Hair shampoo containing pregelatinized, cross-linked starch derivatives,

US Patent 7,279,449, Oct 9, 2007, assigned to Beiersdorf A.G.

59. F Simonet and L Nicolas-Morgantini, Cosmetic composition of water-in-water emulsion

type based on surfactants and cationic polymers, US Patent 20070237733, Oct 11, 2007.

60. VM Coessens, K Matyjaszewski, Fundamentals of Atom Transfer Radical Polymerization,

J Chem Ed, 87, 916-919 (2010).

61. C Farcet, Gradient copolymer, composition including same and cosmetic make-up or

care method; US Patent Application 20090047308, Feb 19, 2009, assigned to LOreal.

62. N Cadena, et al, Method for depositing a polymer onto a surface by applying a

composition onto said surface, USPatent 6,906,128, June 14, 2005, assigned to Rhodia

Chemie.

63. V Bergeron, et al, US Patent 7,335,700, Feb 26, 2008; US Patent 7,915,212, March 29,

2011; and US Patent 7,939,601, May 10, 2011, assigned to Rhodia Inc.

64. Q Stella, Shampoo containing a silicone in water emulsion, US Patent Application

20030143177, July 31, 2003, assigned to the Procter & Gamble Company.

65. DR Royce and RL Wells, Shampoo containing an alkyl ether, US Patent 7,087,221,

Aug 8, 2006, assigned to the Procter & Gamble Company.

66. DR Royce and RL Wells, Shampoo containing an ester oil, US Patent application

20030138392, July 24. 2003, assigned to the Procter & Gamble Company.

67. AJ OLenick, Jr, et al, Personal care products based upon surfactants based upon alkyl

polyglucoside quaternary compounds, US Patent 6,881,710, April 19, 2005, assigned to

Colonial Chemical Inc.68. MJ Cooke, et al, Conditioning shampoo comprising an aqeuous conditioning gel phase

in the form of vesicles,US Patent Application 20110243870, Oct 6, 2011.

69. S Midha, et al, Shampoo containing hollow particles, US Patent Application

20030086896, May 8, 2003, assigned to The Procter & Gamble Company.

70. S Midha, BD Hofrichter, Composition for improving hair volume, US Patent Application

20030091521, May 15, 2003, assigned to The Procter & Gamble Company.


40/42


114

71. RL Wells, ES Johnson, Shampoo containing a cationic guar derivative, US Patent

6,930,078, Aug 16, 2005, assigned to The Procter & Gamble Company.

72. SM Niemiec, et al, Detergent composition with enhanced depositing, conditioning and

softness capabilities, US Patent 6,495,498, Dec 17, 2002; US Patent 6,858,202, Feb

22, 2005; US Patent 6,908,889, June 21, 2005, assigned to The Procter & GambleCompany.

73. MF Neibauer, et al, Personal care compositions comprising a non-binding thickener with

a metal ion, US Patent Application 20070009472, Jan 11, 2007, assigned to The Procter

& Gamble Company.

74. IC Constantinides, et al, Personal care compositions comprising responsive particles,

US Patent Application 20070196299, Aug 13, 2007, assigned to The Procter & Gamble

Company.

75. T Yeoh, et al, Conditioning shampoo compositions having improved silicone deposition,

US Patent 6,200,554; March 13, 2001, assigned to The Procter & Gamble Company.

76. DR Weimer, Liquid detergent compositions, US Patent 3,718,609, Feb 27, 1973, assigned

to Continental Oil Company.

77. Olson, Shampoo composition possessing separate lotion phase, US Patent 3,810,478,

May 14, 1974, assigned to Colgate-Palmolive Company.

78. JR Williams, et al Separating multiphase personal care composition in a transparent or

translucent package, US Patent 6,429,177, Aug 6, 2002, assigned to Unilever Home &

Personal Care USA, division of Conopco, Inc.

79. C Littau, et al, Multiphase aqueous cleaning compositions, US Patent 7,012,049, March

14, 2006,assigned to Clariant International Ltd.

80. KS Wei, et al, US Patent Application 20050100570, May 12, 2005, assigned to The

Procter & Gamble Company.

81. JA Wagner, et al, US Patent Application 20050192188, Sept 1, 2005, assigned to The

Procter & Gamble Company.

82. LS Tsaur, Personal polymer liquid cleansers stabilized with starch structuring system,

US Patent 6,903,057, June 7, 2005, assigned to Unilever Home & Personal Care USA,

division of Conopco, Inc.

83. SPJ Ugazio, Polymer carriers and process, US Patent Application 20050203215,

Sept 15, 2005, assigned to Rohm & Haas Company.

84. RL Wells and ES Johnson, Shampoo containing a cationic guar derivative, US Patent

6,930,078, Aug 16, 2005, assigned to The Procter & Gamble Company.

85. Q Qiu, et al, Ordered liquid crystal cleansing composition with C16-24 normal

monoalkylsulfosuccinates and C16-24 normal alkyl carboxylic acids, US PatentApplication 20050136026, June 23, 2005, assigned to Unilever Intel lectual Property

Group.

86. JJ Guth, DL Spilatro, RJ Verdicchio, Detergent compositions, US Patent 4,435,300,

March 6, 1984, assigned to Johnson & Johnson Baby Products Company.

87. SK Pratley, Aqueous cleansing composition, US Patent6,001,787, Dec 14, 1999,

assigned to Helene Curtis, Inc.

88. MR Sivik, et al, Compositions and method for using amine oxide monomeric unit

containing suds enhancers, US Patent 6,900,172, May 31, 2005, assigned to

the Procter & Gamble Company.

89. RW Glenn Jr., et al, Personal care compositions, especially those personal carecompositions in the form of an article that is a porous, dissolvable solid structure,

US Patent Application 20090232873, Sept 17, 2009.

90. DJ Evans, et al, Separation and analysis of the surface lipids of the wool fiber, Proc. 7th

Int. Wool Text. Res. Conf.,Tokyo, Japan, I, 135142 (1985).

91. PW Wertz and DT Downing, Integral lipids of human hair, Lipids, 23, 878881 (1988).


41/42

Chapter 3

115

92. PW. Wertz and DT Dowing, Integral lipids of mammalian hair, CompBiochem Physiol,

92B, 759761 (1989).

93. U Kalkbrenner, et al, Studies on the composition of the wool cuticle, Proc. 8th Int.

Wool Text. Res. Conf., Christchurch, New Zealand, I, 398 (1990); CM Carr, et al, X-ray

photoelectron spectroscopic study of the wool fiber surface, Textile Res J, 56, 457(1986); S Breakspear, et al, Effect of the covalently linked fatty acid 18-MEA on the

nanotribology of hairs outermost surface,J Struct Biol, 149, 235242 (2005); CA Torre,

et al, Nanotribological effects of silicone type, silicone deposition level, and surfactant

type on human hair using atomic force microscopy,J Cosmet Sci,57, 3756 (2006);

M Yasuda,J Hair Sci,95, 712 (2004); ML Tate, et al, Quantification and prevention of hair

damage,J Soc Cosmet Chem, 44, 347371 (1993).

94. H Tanamachi, et al, Deposition of 18-MEA onto alkaline-color-treated weathered hair to

form a persistent hydrophobicity,J Cosmet Sci,60,3144 (2009).

95. JJ Sabelko, et al, Low molecular weight ampholytic polymers for personal care

applications, US Patent Application 20070207106, Sept 6, 2007, assigned to the Nalco

Company.

96. L Chrisstoffels, et al, Polymers comprising diallylamines, US Patent Application

20070191548, Aug 16, 2007.

97. ES Baker, et al, Conditioning composition comprising aminosilicone, US Patent

8,017,108, Sept 13, 2011, assigned to the Procter & Gamble Company.


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