Entropically driven colloidal crystallization on patterned surfaces

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Original entry: Hsin-I Lu, APPHY 225, Fall 2009

"Entropically driven colloidal crystallization on patterned surfaces"

Keng-hui Lin, John C. Crocker, Vikram Prasad, Andrew Schofield, D. A. Weitz, T. C. Lubensky, and A. G. Yodh, PRL 85, 1770 (2000)

Summary

This paper studies the self-assembly of colloidal spheres on periodically patterned templates which are made from polymethylmethacrylate. Sefl-assembly of colloids in this system is induced entropically by the presence of dissolved, nonadsorbing polymers. Either colloids adsorbing on the templates or two colloids overlaping with each other can create more space for polymers in the system. Therefore, free energy reduction due to these two process can provide attractive forces between colloids and the templates. The authors observed two-dimensional fluidlike and solidlike phases form on templates with both one- and two-dimensional symmetry. The same methodology was then used to nucleate an oriented single fcc crystal more than 30 layers thick.

Soft Matter Keywords

Colloids, colloidal self-assembly, polymer, osmotic pressure, pair correlation function

Soft Matter