Expansion and rupture of charged microcapsules

Citation:

Datta, S. S. ; Abbaspourrad, A. ; Weitz, D. A. Expansion and rupture of charged microcapsules. Mater. Horiz. 2014, 1 92-95. Copy at http://www.tinyurl.com/ly8kh2a

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.

Publisher's Version

Last updated on 08/10/2014