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Nano technologyNano technology
John SummerscalesSchool of Marine Science and Engineering
University of Plymouth
Orders of magnitudeOrders of magnitude
* note that capital K is used, in computing, to represent 210 or 1024, while k is 1000.
x 10-x 10+x
3 milli- (m) kilo- (k)*
6 micro- (μ) mega- (M)
9 nano- (n) giga- (G)
12 pico- (p) tera- (T)
15 femto- (f) peta- (P)
18 atto- (a) exa- (E)
Sub-metre scalesSub-metre scales
atto- femto- pico- nano- micro- milli- metre
0.0532 nm = radius of 1s electron orbital
0.139 nm = C-C bond length in benzene
0.517 nm = lattice constant of diamond
NanostructuresNanostructures surface structures with feature sizes
from nanometres to micrometres white light optics limited to ~1μm use electron-beam or x-ray lithography
and chemical etching/deposition image = calcium fluoride
analog of a photoresist fromhttp://mrsec.wisc.edu/seedproj1/see1high.html
CarbonCarbonElemental carbon may be
• amorphous
or one of two crystalline forms:• diamond (cubic crystal sp3 structure) • graphite (contiguous sp2 sheets)
• graphene (single atom thickness layers of graphite)
or at nanoscale can combine to form• spheres (buckminsterfullerenes or “bucky balls”)• and/or nanotubes
GrapheneGraphene
single atom thickness layers of graphite• thinnest material known• one of the strongest materials known• conducts electricity as efficiently as copper• conducts heat better than all other materials• almost completely transparent• so dense that even the helium atom
cannot pass through
http://www.graphene.manchester.ac.uk/
GrapheneGraphene
Property Units Magnitude Comment Source
Thickness nm 0.33* [1]
Areal density μg/m2 770 ~1g / football field [2]
Tensile modulus GPa 500 [2]
Tensile strength GPa 1000 ~333x virgin CF [1]
Transparency % absorption 2.3 [1]
* in-plane bond length = 0.142 nm (vs 0.133 for C=C bond)
1.http://www.graphene.manchester.ac.uk/story/properties/
2.http://www.graphenea.com/pages/graphene-properties
Penta-graphenePenta-graphene
announced Feb. 2015 stable to 1000K (727ºC) semiconductor auxetic
image from http://www.pnas.org/content/suppl/2015/01/27/1416591112.DCSupplemental/pnas.1416591112.sapp.pdf
NanotubesNanotubes
Carbon-60 bucky-balls (1985) graphitic sheets seamlessly wrapped
to form cylinders (Sumio Iijima, 1991) few nano-meters in diameter, yet
(presently) up to a milli-meter long
Image from http://www.rdg.ac.uk/~scsharip/tubes.htm
NanotubesNanotubes SWNT =
single-wall nano-tube• benzene rings may be
• zigzag: aligned with tube axis• armchair: normal to tube axis• chiral: angled to tube axis
• Image fromhttp://www.omnexus.com/documents/shared/etrainings/541/pic1.jpg via
http://www.specialchem4polymers.com/resources/etraining/register.aspx?id=541&lr=jec
MWNT = multi-wall nano-tube• concentric graphene cylinders
Nanotube productionNanotube production arc discharge through high purity graphite
electrodes in low pressure helium (He) laser vapourisation of a graphite target
sealed in argon (Ar) at 1200°C. electrolysis of graphite electrodes immersed
in molten lithium chloride under an Ar. CVD of hydrocarbons
in the presence of metals catalysts. concentrating solar energy onto
carbon-metal target in an inert atmosphere.
Nanotube purificationNanotube purification
oxidation at 700°C (<5% yield) filtering colloidal suspensions ultrasonically assisted microfiltration microwave heating together with acid
treatments to remove residual metals.
Nanotube propertiesNanotube properties
SWNT (Yu et al)• E = 320-1470 (mean = 1002) GPa• σ´ = 13-52 (mean = 30) GPa
MWNT (Demczyk et al)• σ´ = 800-900 GPa• σ´ = 150 GPa
2D group IV element monolayers2D group IV element monolayers
Central column of periodic table
(covalent bonding atoms)graphene (2D carbon)silicene (2D silicon) unstablegermanene (2D germanium) rarestanene (2D tin)plumbene (2D lead) not attempted ?
CurranCurran®®: carrot fibres: carrot fibres
CelluComp (Scotland)• nano-fibres extracted from vegetables• carrot nano-fibres claimed to have:
• modulus of 130 GPa• strengths up to 5 GPa• failure strains of over 5%
• potential for turnips, swede and parsnips• first product is "Just Cast" fly-fishing rod.
Exfoliated claysExfoliated clays
layered inorganic compoundswhich can be delaminated
most common smectite clay used for nanocomposites is montmorillonite• plate structure with a
thickness of one nanometre or less and an aspect ratio of 1000:1(hence a plate edge of ~ 1 μm)
Exfoliated claysExfoliated clays
Relatively low levels of clay loadingare claimed to:• improve modulus• improve flexural strength• increase heat distortion temperature• improve gas barrier properties• without compromising impact and clarity
nano-technologynano-technologyfabrication .. and .. probesfabrication .. and .. probes
chemical vapour deposition electron beam or UV lithography pulsed laser deposition
atomic force microscope scanning tunnelling microscope superconducting quantum interference
device (SQUID)
Atomic force microscopeAtomic force microscope
image from http://en.wikipedia.org/wiki/Atomic_force_microscope
measures force and deflection at nanoscale
Scanning tunnelling microscopeScanning tunnelling microscope
scans an electrical probe over a surface to detect a weak electric currentflowing between the tip and the surface
image fromhttp://nobelprize.org/educational_games/physics/microscopes/scanning/index.html
Superconducting QUantum Superconducting QUantum Interference Device (SQUID)Interference Device (SQUID)
measures extremely weak magnetic signals e.g. subtle changes in the electromagnetic
energy field of the human body.
MEMS: micro electro MEMS: micro electro mechanical systemsmechanical systems
Microelectronics and micromachiningon a silicon substrate
MEMS electrically-driven motors smaller than the diameter of a human hair
Image from http://www.memsnet.org/mems/what-is.html
Controlled crystal growthControlled crystal growth
Brigid Heywood• Crystal Science Group at Keele
controlling nucleation and growthof inorganic materialsto make crystalline materials
protein templates
AcknowledgementsAcknowledgements
Various websites from whichimages have been extracted
To contact me:To contact me: Dr John SummerscalesACMC/SMSE, Reynolds Room 008
University of Plymouth
Devon PL4 8AA 01752.23.2650 01752.23.2638 [email protected] http://www.plym.ac.uk/staff/jsummerscales