Expansion and rupture of charged microcapsules

Sujit S. Datta; Alireza Abbaspourrad; David A. Weitz

doi:10.1039/c3mh00099k

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arXiv · 1401.8270

Expansion and rupture of charged microcapsules

Sujit S. Datta·Alireza Abbaspourrad·David A. Weitz

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Abstract

We study the deformations of pH-responsive spherical microcapsules -- micrometer-scale liquid drops surrounded by thin, solid shells -- under the influence of electrostatic forces. When exposed to a large concentration of NaOH, the microcapsules become highly charged, and expand isotropically. We find that the extent of this expansion can be understood by coupling electrostatics with shell theory; moreover, the expansion dynamics is well described by Darcy's law for fluid flow through the microcapsule shell. Unexpectedly, however, below a threshold NaOH concentration, the microcapsules begin to disintegrate, and eventually rupture; they then expand non-uniformly, ultimately forming large, jellyfish-like structures. Our results highlight the fascinating range of behaviors exhibited by pH-responsive microcapsules, driven by the interplay between electrostatic and mechanical forces.

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Sujit S. Datta, Alireza Abbaspourrad, David A. Weitz. 2014-01-31. Expansion and rupture of charged microcapsules. https://doi.org/10.1039/c3mh00099k

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