Soft Condensed MatterSoft Condensed Matter**& &

Advanced Colloid ScienceAdvanced Colloid Science

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 ChemistryProf. Dr. Willem Kegel, Dr. Gert Jan Vroege,

Prof. Dr. Henk Lekkerkerker

Condensed Matter & InterfacesProf. Dr. Daniël Vanmaekelbergh

Physics Department:

Soft Condensed MatterSoft Condensed MatterDr. 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 Lecture09.45 – 10.00 Break10.00 – 10.45 Lecture10.45 – 11.00 Coffee & Cookies11.00 – 12.30 Problem Classes12.45 – 14.00 Lunch (Minnaert Cantine)14.00 – 14.45 Lecture14.45 – 15.00 Break15.00 – 15.45 Lecture15.45 – 16.00 Coffee & Cookies16.00 – 17.30 Problem Classes

Monday April 23rd16:00 Posters (BBL105b)

Wednesday April 25th16:00 Lab Tours

Logistics

Computer Facilities:Login: kolloidPsswd: as5kj5bd

Assistants:Dannis ‘t HartAndrea Fortini

Alfons van Blaaderen, Ornstein Lab. 62, 030 (253)-2204

A.vanBlaaderen@phys.uu.nl 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 subject (~20 min)

-Subjects follow

Exam: -Subject matter as in reader (Chapter 1 t/m 11, for 11

see lecture notes)

18 April

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

2 Shear stressStrain rate

pFL

vL

η = =

(strain rate = shear rate γ)

Incompressible Newtonian liquid: Navier-Stokes Equations

Sphere (stick boundary conditions) Friction factor: f = 6π η R

Complex Fluids

•‘Simple/Conventional’ Liquids Flow, Solids YieldLiquids 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 byapplication 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?

2pF L

L Lµ ∆

= Stress = Shear Modulus * Strainµ = [energy/length3]

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

µ = 214 GPa

1 mole Ni atoms in a crystal: 10 cm

1 mole 1 µm colloids in a crystal: 84 mµ = 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 manysubunits 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 1Dand positional order in at most 2D

•Liquid Crystals:Thermotropic, Lyotropic, Colloidal

nematic

Liquid Crystalssmecticcholesteric

•L. Reinitzer (1888): two separate melting temperatures in cholesterol nonanoate

•Otto Lehmann: phase changes were thermodynamictransitions

•G. Friedel (1920s): new LC phases, classification of defects

Surfactants

•Amphiphiles or surfactants have a schizophreniccharacter: 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

semi permeable membrane

Π

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

Colloids

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

Medium Particle NameLiquid Solid Colloidal Sol, Colloidal …Liquid Liquid (micro)EmulsionLiquid Gas FoamGas 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

20( ) 2x t D t=

0 6π RkT kTDf η

= =

Colloids have a Thermodynamic TemperatureBrownian Motion Explained and Measured -> NA

Fluctuation - Dissipation

(1827)

Colloids as Molecules: Perrin

J. Perrin (1870-1942) Nobel prize Physics 1926“For his work on the discontinuous structure of matter, and especially for his discovery of sedimentation equilibrium.”

10 µm

•Microscopy

•Model Particles

•External Fields

"I did not believe that it was possible to study the Brownian motion with such a precision."

From a letter from Einstein to Perrin (1909).

Colloids in External Fields: Perrin

Barometric height distribution -> colloids in external field

/( ) gh ln h e−∝

gkTlmg

=∆

‘Ideal Gas’ Behavior

The Incredible Shrunken Student Part IWhat 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 hewill 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 aswimming champion, he will drown, because hecannot make use of inertial effects.

The Incredible Shrunken Student Part IICan his girlfiend who starts watching him with a powerful microscope see that he is dead?

•No not only will he be subject to significant Brownianmotion, 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 chargeis 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, Aeff = 10-20 J, ζ = 50 mV, ε = 102

Coarse Graining

6πf Rη=

6π RBm mf

τη

= =2

HRρτη

=

eURR ρη

≡

Swimming Bacteria cannot Coast

Rhodospirilum (5-10 micron long)

Coarse Graining

20( ) 2x t D t=

0 6π RkT kTDf η

= =

2 32 12I

R f RkT kT

π ητ = =

Coarse Graining

2B

mkTlf

=6π RBm mf

τη

= =

229s

R gU ρη∆

=0

2 se

RUPD

=

gkTlmg

=∆

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, Aeff = 10-20 J, ζ = 50 mV, ε = 102

Characteristic Forceselectrical forceBrownian force

20R

kTεε ζ

~102

effAkT

Van der Waals forceBrownian force

~1

2URkT

η viscous forceBrownian force

~1

3R gURρη∆ gravitational force

viscous force~10-1

2 2R UUR

ρη

inertial forceviscous force

~10-6

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

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

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

Predicted by John Conway, Neil Sloane et al.Manoharan et al., Science, 301, 483 (2003)

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 biologicalactin filament attached

Mixture of virus particles (polarization)microscopy imagesM. 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 ScatteringColloid (few micron)

Dye

Electric Field Switches ColloidsSteric 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

PhilipsNature Mater. (2002)

Electronic Ink Next Generation

Bragg-diffraction with Light

d ~ 300 nmdus

d ~ λvisible

Natural Opal, a half-gem stone, made from silica spheres in a silicate setting.

Synthetic opal: colloidal crystal 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

High E-field Strong Dipoles Yield stress: Electro-Rheological fluid

No E-field low viscosity liquid

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