Issue 44, 2016

Swelling, structure, and phase stability of compressible microgels


Microgels are soft colloidal particles that, when dispersed in a solvent, swell and deswell in response to changes in environmental conditions, such as temperature, concentration, and pH. Using Monte Carlo simulation, we model bulk suspensions of microgels that interact via Hertzian elastic interparticle forces and can expand or contract via trial moves that allow particles to change size in accordance with the Flory–Rehner free energy of cross-linked polymer gels. We monitor the influence of particle compressibility, size fluctuations, and concentration on bulk structural and thermal properties by computing particle swelling ratios, radial distribution functions, static structure factors, osmotic pressures, and freezing densities. For microgels in the nanoscale size range, particle compressibility and associated size fluctuations suppress crystallization, shifting the freezing transition to a higher density than for the hard-sphere fluid. As densities increase beyond close packing, microgels progressively deswell, while their intrinsic size distribution grows increasingly polydisperse.

Graphical abstract: Swelling, structure, and phase stability of compressible microgels

Article information

Article type
08 Sep 2016
17 Oct 2016
First published
17 Oct 2016
This article is Open Access
Creative Commons BY license

Soft Matter, 2016,12, 9086-9094

Swelling, structure, and phase stability of compressible microgels

M. Urich and A. R. Denton, Soft Matter, 2016, 12, 9086 DOI: 10.1039/C6SM02056A

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