Past Seminars Seminários Já Decorridos 2014

Patchy colloidal assembly

By: Peter D. J. van Oostrum
From: University of Natural Resources and Life Sciences, Vienna
At: Instituto de Investigação Interdisciplinar, Anfiteatro
[2014-12-04] 14:40

(Note that we will have two seminars: one at 2pm and the other at 2:40pm)

Self-assembly is the process by which small units collectively form larger structures while minimizing the free energy. This process is ubiquitous in nature and relies on thermal fluctuations to sample various configurations. I focus on rather large self-assembling units; colloidal particles. These have the advantage over molecules that they can be studied in real-time and space using various light microscopy techniques. Patchy particles exhibit direction dependent interactions that direct the assembly in new structures. The interaction between heterogeneously charged particles offers interesting perspectives. I present a novel and utterly simple method to synthesize such particles in the lab [1]. Patchy particles can also be used to model and study the self-assembly of peptides. The sequence of the amino acids in proteins dictates their folded 3-D structure. We have recently shown in simulations that this principle can be applied to flexible strings of isotropically interacting particles with an attractive patchy interaction, allowing the design of new materials and structures [1-2]. Our goal is now to realize this directed self-folding on a colloidal size scale to study the folding in real time in real space [3]. I will discuss how I want to realize that using induced dipole interactions, microfluidics and partial melting of the particles. 

[1] P.D.J. van Oostrum, M. Hejazifar, C. Niedermayer and E. Reimhult, Simple synthesis method of Inverse Patchy Colloids, In preparation

[2] I. Coluzza, P.D.J. van Oostrum, B. Capone, E. Reimhult, C. Dellago, Sequence controlled self-knotting colloidal patchy polymers, Physical Review Letters, 110, 075501, 2013

[3] I. Coluzza, P.D.J. van Oostrum, B. Capone, E. Reimhult, C. Dellago, Design and folding of colloidal patchy polymers, Soft Matter, 9, 938-944, 2013

[4] H.R. Vutukuri, A.F. Demirörs, B. Peng, P.D.J. van Oostrum, A. Imhof, A. van Blaaderen, Colloidal Analogues of Charged and Uncharged Polymer Chains with Tunable Stiffness, Angewandte Chemie International Edition, 51, 45, 11249–11253,  2012