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Slippery Solutions for Sticky Problems TM www.slipstechnologies.com

Sirris Smart coating roadshow - Slips introduction 1

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Page 1: Sirris Smart coating roadshow - Slips introduction 1

Slippery Solutions for Sticky ProblemsTM

www.slipstechnologies.com

Page 2: Sirris Smart coating roadshow - Slips introduction 1

‘Sticky’ Problems!

Page 3: Sirris Smart coating roadshow - Slips introduction 1

Wetting of Liquid on Solid Surface

Young (1805)

Wenzel (1936)

Cassie-Baxter (1944)

Cassie (1948)

γLVcos𝜃 = γSV − γLS

cos𝜃* = rcos𝜃

cos𝜃* = -1 + ɸs(cos𝜃 +1)

cos𝜃* = A1cos𝜃1 + A2cos𝜃2

solid

vapor

liquid𝜃

contact angle (CA): 𝜃

ideal flat

texturedwetted

texturednon-wetted

chemicallyheterogeneous

Page 4: Sirris Smart coating roadshow - Slips introduction 1

Removal of Liquid on Solid Surface

𝜃R𝜃A

α

gravity

contact angle hysteresis (CAH): 𝜃A - 𝜃R

γLV (cosθR – cosθA) = mg sinα/w Furmidge (1962)

minimizing liquid pinning is the KEYto extreme liquid repellency

solid

𝜃R𝜃A

α

Gibbs (1873)Dyson (1988)

Oliver, Huh, Mason (1977)

θ ≤ θA ≤ θ + (180° - β) Gibbs Inequalities:

𝜃𝜃

β

𝜃A

solidrough solid

Page 5: Sirris Smart coating roadshow - Slips introduction 1

Water-Repellent, Self-Cleaning Surfaces in Nature

20µm

200 nm

Planta 202 1-8 1997!

Nature 432 36 2004!

Soft Matter 3 178-182 2007!

Page 6: Sirris Smart coating roadshow - Slips introduction 1

Water-Repellent, Self-Cleaning Surfaces in Nature

20µm

200 nm

Planta 202 1-8 1997!

Nature 432 36 2004!

Soft Matter 3 178-182 2007!

Lessons learned from Nature:•  Often hierarchical structures•  Covered with hydrophobic materials•  High contact angles

Page 7: Sirris Smart coating roadshow - Slips introduction 1

Bio-inspired Superhydrophobic Surfaces

Wenzel

State

low surface tension liquidhigh temperature

high pressuremechanical damage

high humidity

‘sticky’droplet

Cassie-BaxterState

‘non-sticky’ droplet

Page 8: Sirris Smart coating roadshow - Slips introduction 1

A Radically Different Strategy

•  Can we make the surface ‘slippery’?- ultrasmooth interface�- essentially eliminates ‘pinning points’ �- can we (practically) do this with a solid material?

•  What about using a ‘liquid’?�- but how can we hold such liquid?�- what about using non-interacting, immiscible liquid (e.g. PFPE, silicone)?

•  Of course, durability, scale-up, manufacturing, and cost are the pressing issues

Page 9: Sirris Smart coating roadshow - Slips introduction 1

Tree2(12)364–369(1987),PNAS10114138–14143(2004),Proc.R.Soc.B(2008),PlantSignaling&Behavior(2009),Prog.Nat.Sci.(2009)

Another Source of Inspiration:Carnivorous Nepenthes Pitcher Plant

Page 10: Sirris Smart coating roadshow - Slips introduction 1

Tree2(12)364–369(1987),PNAS10114138–14143(2004),Proc.R.Soc.B(2008),PlantSignaling&Behavior(2009),Prog.Nat.Sci.(2009)

Lessons learned from Nature:•  Immiscible liquid layer

•  Chemical Affinity•  Capillarity

Another Source of Inspiration:Carnivorous Nepenthes Pitcher Plant

Page 11: Sirris Smart coating roadshow - Slips introduction 1

Pitcher Plant-Inspired Surface and Coating

Slippery Liquid-Infused Porous Surfaces

infuse witha lubricant

liquid/solidbeing repelled

surface functionalization/conditioningsurface

roughening

self-healing and repellent !lubricating film in and on a porous solid!

• Sub-nanometer smoothness• Excellent repellency to almost everything • High pressure/temperature tolerance• Self-healing characteristics• Highly customizable system

Key Features Nature 477 443-447 2011!ACS Nano 6(8) 6569-6577 2012!PNAS 109(33) 13182-13187 2012!PCCP 15 581-585 2013!Nano Lett. 13(4) 1793-1799 2013!Nature Materials 12 529-534 2013!Appl. Phys. Lett. 102 231603 2013!Nature Commun. 4 2013!Nanotechnology 25 2013!Angew. Chem. Int. Ed. 53 2014!

Page 12: Sirris Smart coating roadshow - Slips introduction 1

Design Principle: Modeling the Film Stability

Wong et al., Nature 477 443-447 2011!

Page 13: Sirris Smart coating roadshow - Slips introduction 1

Teflon vs. Superhydrophobic vs. SLIPS

Page 14: Sirris Smart coating roadshow - Slips introduction 1

Crude Oil Blood

Stable up to 250°C and ~700 atm (10,000 psi)

Wong et al., Nature 477 443-447 2011!

Temperature Resistance Self-healing

Page 15: Sirris Smart coating roadshow - Slips introduction 1

SLIPS Prevent Bacterial Biofilm Formation�(static culture)

Epstein et al., PNAS 109(33) 13182-13187 2012!

Page 16: Sirris Smart coating roadshow - Slips introduction 1

Epstein et al., PNAS 109(33) 13182-13187 2012!

CtrlPTFE SLIPS

P. aeruginosa in media is pumped through PTFE and SLIPS PTFE tubing

48 hour growth10 mL/min flow

SLIPS Prevent Bacterial Biofilm Formation�(under flow)

Page 17: Sirris Smart coating roadshow - Slips introduction 1

Yet another approach to create ‘liquid interface’

Page 18: Sirris Smart coating roadshow - Slips introduction 1

SLIPS vs. Biofouling (Lab Test)

Chlamydomonas reinhardtii algal biofilm, 2 weeks culture

Page 19: Sirris Smart coating roadshow - Slips introduction 1

R-SLIPS against Marine Biofouling (Field Test)

silicone coating

Page 20: Sirris Smart coating roadshow - Slips introduction 1

Slippery Solutions for Sticky ProblemsTM

www.slipstechnologies.com

Thank You!!