SoftSoft CondensedCondensed MatterMatter** & AdvancedAdvanced ColloidColloid ScienceScience

Utrecht University, April 2007, The Netherlands PhD/*Prestige Masters Course

WWW.COLLOID.NL Utrecht University

13 Permanent Staff working on Colloids: Experiments, Theory, Simulations

Former Debye Institute for NanoMaterials: Colloids, Catalysis & NanoPhotonics Chemistry & Physics Groups Lecturers

Chemistry Department:

Van ‘t Hoff lab., Physical & Colloid Chemistry Prof. Dr. Willem Kegel, Dr. Gert Jan Vroege, Prof. Dr. Henk Lekkerkerker

Condensed Matter & Interfaces Prof. Dr. Daniël Vanmaekelbergh

Physics Department:

Soft Condensed Matter Dr. Arnout Imhof, Dr. Marjolein Dijkstra, Dr. René van Roij* Prof. Dr. Alfons van Blaaderen

*Theoretical Institute Logistics

Two Weeks Course Minnaert Building 205

09.00 – 09.45 Lecture Monday April 23rd 09.45 – 10.00 Break 16:00 Posters (BBL105b) 10.00 – 10.45 Lecture 10.45 – 11.00 Coffee & Cookies 11.00 – 12.30 Problem Classes 12.45 – 14.00 Lunch (Minnaert Cantine) 14.00 – 14.45 Lecture 14.45 – 15.00 Break Wednesday April 25th 15.00 – 15.45 Lecture 16:00 Lab Tours 15.45 – 16.00 Coffee & Cookies 16.00 – 17.30 Problem Classes Logistics

Computer Facilities: Login: kolloid Psswd: as5kj5bd

Assistants: Dannis ‘t Hart Andrea Fortini

Alfons van Blaaderen, Ornstein Lab. 62, 030 (253)-2204 [email protected] www.colloid.nl Course Contents Week I

1. Introduction SCM (AvB) 2. Classical Ensemble Theory (RvR) 3. Liquid State Theory: Classical Fluids (RvR) 4. Static & Dynamic Scattering Techniques (AI) 5. Computer Simulations (MD) 6. Interface Thermo / Surfactants (LC’s) (WK) 7. Polymers (GJV) 8. Quantum Dots (DV) Contents Masters Course

Assignment: -Write a review over a current (couples) soft matter subject (~10 pages) -Give a presentation on the same 18 April subject (~20 min) -Subjects follow

Exam: -Subject matter as in reader (Chapter 1 t/m 11, for 11 see lecture notes) 2 May Course Contents Week II

9. DLVO Potential & Measurements of Interaction Forces (AvB) 10.Liquid Crystals (RvR) 11.Colloid Synthesis (AvB) 12.Dynamics (AI/HL) 13.Phase Behavior (HL)

1-11 Masters Course 12-13 Advanced Colloids Contents Today

•Soft Condensed Matter vs. Complex Fluids •Examples and (Historical Notes): Colloids, Polymers, Liquid Crystals, Surfactants •Coarse Graining and Characteristic Forces •Colloids vs Soft Matter •Crossroad of Disciplines and Fields •Connection with Nano-Science and Technology Mechanics Intermezzo

For small enough deformations Solids Yield -> ‘3D Hooks Law’ : Elastic Moduli

Fluids Flow: viscosity η

Fp 2 Shear stress η ==L v Strain rate L (strain rate = shear rate γ)

Incompressible Newtonian Sphere (stick boundary conditions) liquid: Navier-Stokes Equations Friction factor: f = 6π η R Complex Fluids

•‘Simple/Conventional’ Liquids Flow, Solids Yield Liquids are isotropic, solids are anisotropic

•Complex Fluids are intermediate between a solid or liquid: -they are viscoelastic or -change from solid to liquid or vice versa by application of a small field -flow but have anisotropic mechanical properties

•Have a large (but not too large) length scale in at least 1D, compared with molecular dimensions Why Soft Condensed Matter?

F ∆L p = µ Stress = Shear Modulus * Strain L2 L µ = [energy/length3]

L ~ 103-104 larger ⇒ µ = 109-1012 larger

1 mole Ni atoms in a crystal: 10 cm µ = 214 GPa

1 mole 1 µm colloids in a crystal: 84 m µ = 14 Pa Contents Today

•Soft Condensed Matter vs. Complex Fluids •Examples and Historical Notes: Colloids, Polymers, Liquid Crystals, Surfactants •Coarse Graining and Characteristic Forces •Colloids vs Soft Matter •Crossroad of Disciplines and Fields •Connection with Nano-Science and Technology Polymers

•Polymers are macromolecules that consist of many subunits connected to each other through chemical bonds •DNA, proteins, dendrimers, star polymers

H. Staudinger (1920): Macromolecules with covalent bonds

Carothers (1931): Production of Nylon

W. Kuhn (1934) : Probability distribution of a random coil Liquid Crystals

•Liquid Crystals have orientational order in at least 1D and positional order in at most 2D •Liquid Crystals: Thermotropic, Lyotropic, Colloidal

nematic Liquid Crystals cholesteric smectic

•L. Reinitzer (1888): two separate melting temperatures in cholesterol nonanoate •Otto Lehmann: phase changes were thermodynamic transitions •G. Friedel (1920s): new LC phases, classification of defects Surfactants

•Amphiphiles or surfactants have a schizophrenic character: one end like oil, the other water Surfactants Historic Notes

•Benjamin Franklin (1757 ): Oil on water, less waves

•Agnes Pockels (1898) & I. Langmuir (1920): Pressure versus area curves for monolayers Osmotic Pressure Π for Colloids

•Thomas Graham (1861), membrane: κολλα = glue

Π

semi permeable membrane

• J. van ‘t Hoff (~1880’s), law: ΠV = nRT Colloids

•Colloid: Particle (solid, liquid, gas) dispersed in a Medium (liquid, gas)

Medium Particle Name Liquid Solid Colloidal Sol, Colloidal … Liquid Liquid (micro)Emulsion Liquid Gas Foam Gas Solid/Liquid Aerosol

•Monodisperse, Polydisperse, Polydispersity Contents Today

•Soft Condensed Matter vs. Complex Fluids •Examples and Historical Notes: Colloids, Polymers, Liquid Crystals, Surfactants •Coarse Graining and Characteristic Forces •Colloids vs Soft Matter •Crossroad of Disciplines and Fields •Connection with Nano-Science and Technology Colloids & Condensed Matter

•Separation of Time- and Length-Scales Colloids as Molecules: Perrin - Einstein Colloids have a Thermodynamic Temperature

Brownian Motion Explained and Measured -> NA (1827)

kT kT D0 == f 6πηR 2 xt() = 2D0t Fluctuation - Dissipation Colloids as Molecules: Perrin

"I did not believe that it was possible to study the Brownian motionJ. Perrin with(1870-1942) such a precision." Nobel prize Physics 1926 From “aFor letter his from work Einstein on the discontinuousto Perrin (1909) . structure of matter, and especially for his discovery of sedimentation equilibrium.”

•Microscopy

•Model Particles

•External Fields 10 µm Colloids in External Fields: Perrin

Barometric height distribution -> colloids in external field

nh()∝ e−hl/ g

kT l = g ∆mg

‘Ideal Gas’ Behavior The Incredible Shrunken Student Part I

What happens to the student swimming champion when het is shrunken down to a size of 1 µm right when he was throwing bath salt in his tub before taking a bath?

•Because of his small mass his body will not be able to penatrate the high surface tension of water and he will stay afloat on the surface.

•If he had already thrown in a very effective soap, he will penetrate the water and even though he is a swimming champion, he will drown, because he cannot make use of inertial effects. The Incredible Shrunken Student Part II

Can his girlfiend who starts watching him with a powerful microscope see that he is dead? •No not only will he be subject to significant Brownian motion, he will not have the strength to surmount friction to move his arms.

In trying to save him his girlfriend throws a toothpick in his direction. What will happen? •Because of the bath salt his negative surface charge is screened so much, that Van der Waals forces make him stick irreversibly to the wooden log. Characteristic Forces

R = 1 µm, η = 10-3 kg/ms, U = 1 µm/s, ρ = 103 kg/m3, ∆ρ/ρ = 10-2, g = 10 m/s2, -20 2 Aeff = 10 J, ζ = 50 mV, ε = 10 Coarse Graining

fR= 6πη

mm ρR2 τ B == τ = f 6πηR H η

ρUR R ≡ e η Swimming Bacteria cannot Coast

Rhodospirilum (5-10 micron long) Coarse Graining

2 xt() = 2D0t

kT kT D == 0 f 6πηR

21Rf232π Rη τ == I kT kT Coarse Graining

mm 2mkT τ B == l = f 6πηR B f

2 2Rg∆ρ 2RUs U s = Pe = 9η D0 kT l = g ∆mg Characteristic Forces

R = 1 µm, η = 10-3 kg/ms, U = 1 µm/s, ρ = 103 kg/m3, ∆ρ/ρ = 10-2, g = 10 m/s2, -20 2 Aeff = 10 J, ζ = 50 mV, ε = 10 Characteristic Forces Rεεζ2 electrical force 0 ~102 kT Brownian force A Van der Waals force eff ~1 kT Brownian force ηUR2 viscous force ~1 kT Brownian force

∆ρR3g gravitational force ~10-1 ηUR viscous force

ρR22U inertial force ~10-6 ηUR viscous force Contents Today

•Soft Condensed Matter vs. Complex Fluids •Examples and Historical Notes: Colloids, Polymers, Liquid Crystals, Surfactants •Coarse Graining and Characteristic Forces •Colloids vs other Soft Matter •Crossroad of Disciplines and Fields •Connection with Nano-Science and Materials (Technology) Colloids vs. other Soft Matter

•Last 10 years Distinction between different Soft Matter systems is disappearing:

-Molecular LC’s inside emulsion droplets -Colloids dispersed inside molecular LC phases -Colloidal LC phases (rods, plates)

-Monodisperse polymers: Dendrimers, Star polymers -Polymer colloids with soft interactions -Block co-polymers that self organize into monodisperse micelles -Polymers added to colloids to cause attractions by depletion Colloids vs. other Soft Matter

•Last 10 years Distinction between different Soft Matter systems is disappearing:

-Monodisperse emulsions -Monodisperse colloids made in (micro)emulsions

-Monodisperse colloids from Biology: viruses, DNA Dendrimer & Star Polymer LC emulsion in emulsion

Weitz et al. Monodisperse Emulsion filled with LC

Electric field switchable Photonic crystal Weitz et al., PRL, 92, 105503 (2004) Colloidal LC Phases

Colloidal Rods and Platelets form Nematic LC’s (crossed polarizers) Van ‘t Hoff lab. (UU) Shape Control: Minimal moment clusters, 2-11

PredictedManoharan bye Johnt al., Science Conway,, 301, Neil 483 Sloane(2003) et al. Colloids from Biology

Viruses, DNA….

FD Pig virus, length 900 nm, Diameter ~7 nm Fraden et al. Crossroad of Disciplines and Fields

Optical tweezers grabbing colloidal latex spheres with an biological actin filament attached

Mixture of virus particles (polarization)microscopy images M. Adams, et al., Nature, 393, 349 (1998) : Beads on a Chain: Model BioPolymers

2 µm PMMA spheres Contents Today

•Soft Condensed Matter vs. Complex Fluids •Examples and Historical Notes: Colloids, Polymers, Liquid Crystals, Surfactants •Coarse Graining and Characteristic Forces •Colloids vs other Soft Matter •Crossroad of Disciplines and Fields •Connection with Nano-Science and Materials (Technology) Advanced Functional Materials

Twisted nematic liquid crystal display Electronic Ink

Polymer Capsule

Strongly Scattering Colloid (few micron)

Dye

Electric Field Switches Colloids Steric Stabilization, Van der Waals Attraction, Small Charges, Emulsification

E-ink.com abc technews Electronic Ink Next Generation

Oppositely charged µm sized pigment particles in small polymer containers filled with liquid under appication of E-field

Philips Nature Mater. (2002) Electronic Ink Next Generation Bragg-diffraction with Light

d ~ 300 nm dus

d~ λvisible

Natural Opal, a half-gem stone, made Synthetic opal: colloidal crystal from silica spheres in a silicate setting. made from 300 nm silica spheres. Inverse Silicon FCC Photonic Crystal

Y.A. Vlasov, X.Z. Bo, J.C. Sturm, and D.J. Norris, Nature 414, 289 (2001). Electro-Rheological Fluids

No E-field Æ High E-field Æ Strong Dipoles low viscosity liquid Æ Yield stress: Electro-Rheological fluid Electro-Rheological Fluids NanoScience and NanoTechnology

Self-assembled array of spherical di-block domains are used in lithography to make a pattern of holes or pillars in silicon nitride with dimensions of only a few nm. M. Park, et al., Science, 276, 1401 (1997) Quantum Dots Self Organize

hν Doping a NanoCrystal Transistor

Urban, et al., Nature Mat, 6 (2007) Colloidal NanoCrystals with Shape Control

CdSe Nano Crystals with Shape Control Form LC phases

Alivisatos et al., Nano Lett., 1, 349 (2001) Inspiration from Nature: Diatoms