A tale of patchy colloids: dumbbells and “Mickey Mouse” particles

A Tale of Patchy Colloids: Dumbbells and “Mickey Mouse” Particles

Guido Avvisati Soft Condensed Matter

Utrecht University

Outline

Motivation, introduction to patchy particles

Multipotent self-assembly of patchy dumbbells

Self-assembly of Mickey Mouse (MM) particles in vitro and in silico

Gas-Liquid phase separation vs Self-Assembly for Mickey Mouse particles

Conclusions & Outlook

The main question(s)

Understand the relation between macroscopic properties of a system in terms of its microscopic constituents


micro macro



Bottom Up approach to nanomaterial fabrication

micro macro

micro macro




micro macro

micro macro

Encode Information




micro macro

micro macro

Encode Information What kind of information


The shopping list Glotzer et al., Nat. Mat., 2007, 6, 557

Glotzer et al., Nat. Mat., 2007, 6, 557

The shopping list


Interaction

The shopping list


Interaction

Geometry

Geometry

The shopping list

Patchy Particles: from simple to complex in theory...

Kern N., Frenkel D., J. Chem. Phys., 2003, 118, 9882

Sciortino F. et al, Phys. Rev. Lett, 2009, 103, 237801

Romano F. et al, J. Chem. Phys., 2010, 132, 184501

Romano F. et al, J. Phys. Condens. Matt., 2012, 24, 064113

Whitelam S. et al, Phys. Rev. X, 2014, 4, 011044

...and in practice Wang Y. et al, Nature, 2012, 491, 55

Li F. et al, J. Am. Chem. Soc., 2009, 131, 18548

From model systems... Smallenburg F. et al, Nature Physics, 2014, 10, 653

...to applications

Romano F. and Sciortino F., Soft Matter, 2011, 7, 5799

Chen Q. et al, Nature, 2011, 469, 381 Romano F. et al, J. Chem. Phys., 2010, 132, 184501

Make patchy particles: a dutch recipe

Surface roughness asymmetry

Kraft D. et al, PNAS, 2012, 109, 10787

Synthesis for chemists

Synthesis for chemists

Kraft D. et al, Soft Matter, 2009, 5, 3823

Synthesis for physicists

Synthesis for physicists

Yeah, chemistry!!!!

Outline






Exploring anisotropy: Patchy dumbbells

Model parameters

- Fix strength, - Fix range, - Vary packing fraction, - Vary size ratio, - Vary elongation,

Avvisati G. et al, J. Chem. Phys., 2015, 142, 084905

Multipotent self-assembly of dumbbells

Typical results, size ratio q = 1.035

Structure identification via cluster order parameters

Size ratio q = 1.035

Size ratio q = 1.25

Size ratio q = 0.95

Outline






Exploring anisotropy: “Mickey Mouse” particles

Can we stabilise elongated, tube-like structures from a solution of Mickey Mouse particles?

Dumbbells: “all” but tubes More shielding: tubes?

Kraft D. et al, PNAS, 2012, 109, 10787 Avvisati G. et al, J. Chem. Phys., 2015, 142, 084905

Experiment and Simulations

Colloidal packing fraction: 0.01 Interaction strengths: [-2,-12]kbT Interaction range: 55nm


Clusters are stable for intermediate interaction strengths (~ 7.0kBT)

Analysis

Tubes are kinetically trapped

vav = available volume to a particle in a cluster

Vmm = volume of a mickey mouse particle

∆u = bonding energy

Valid in equilibrium!

Escape times 1 bond: 10s, e ~ 7.0kBT 10m,e ~ 12kBT 2 bonds: 10^5s 4bonds: 10^12s

Wolters J., Avvisati G. et al, Soft Matter, 2015, 11, 1067

Tube structures Two competing structures found in the NVT simulations

Structure: PC vs real life

Outline






Summing up and looking around...

F. Del Rio et al., Mol. Phys., 2002, 100, 2531

Summing up and looking around...

The Inbetweeners

Follow the gas-liquid

(GL) coexistence

curve via a family of

intermediate models

by varying the bond

length distance and

the interaction range

Intermezzo - Successive Umbrella Sampling (SUS)

Allows one to calculate directly the density probability distribution function, P(N)

Inherently parallel algorithm

Cheap with respect to other methods

For fixed temperature, the histogram reweighting technique yields the coexistence Gas (G)-Liquid (L) chemical potential

Intermezzo - Successive Umbrella Sampling (SUS)

Test Case: Square-well fluid

SUS at work

Many temperatures...

Many simulations here: 8 (temperatures) x 800 (windows per temperature)

SUS at work

Final results for Square-well particles G-L coexistence for

Ready to start!

From HSSW to MMSW

Scaling of Critical Temperature with Shape

Structure: Simple vs MM Liquid

Structure: Simple vs MM Liquids

Moving forward

Range-driven Transition to Self-Assembly

Numerically calculate second virial coefficient


r

Clusters appear for


Confirmed by NVT simulations


Tube like structures

Interplay between Phase Separation and Self-Assembly

Geometry cannot alone be responsible for the self-assembly

Shape

Interplay between Phase Separation and Self-Assembly

Geometry cannot alone be responsible for the self-assembly

Shape

Interaction range

Indication of complementary effects


Surface-roughness difference + depletion interactions “easy” method for self-assembly of different shapes Patchy dumbbells achieve multipotent self-assembly

Mickey Mouse particles form tubes under certain conditions, simulations of a simple model are in qualitative agreement with the experiments.

Intriguing interplay between phase separation and self-assembly in fluids of Mickey Mouse particles

How general is this mechanism? Other shapes and interactions

Acnowledgements

Teun Vissers Joost Wolters Fabian Hagemans Daniela Kraft Willem Kegel Marjolein Dijkstra

Acnowledgements

Teun Vissers Joost Wolters Fabian Hagemans Daniela Kraft Willem Kegel Marjolein Dijkstra

Thank you for your attention!

http://www.glitter-graphics.com/graphics/1030943 Mickey Mouse pics from

http://www.disneypictures.net/k-mickey-mouse-14.htm

Question time

A tale of patchy colloids: dumbbells and “Mickey Mouse” particles

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