Shape Control of Deformable Nanocontainers by Modulating Surface Tension and Charge Patterning

Shape-reconfigurable polymeric vesicles, micelles and other soft-matter-based nanomembranes have important applications as adaptive drug-delivery carriers that change shape in response to external cues, and as dynamic building blocks for designing reconfigurable materials. The shape of these nanocontainers can be controlled by modulating their surface composition and environment. Molecular dynamics simulations are used to explore the role of surface tension and surface charge patterning in changing the shape of charged, elastic, volume-preserving nanocontainers. For homogeneously charged nanocontainers, sphere-to-rod-to-disk shape transitions are shown to be facilitated by decreasing surface tension; this could be realized by functionalizing the nanocontainer surface with surfactants. For inhomogeneous, hemispherically-charged Janus nanocontainers, transitions to hemispherical shapes are observed. Shape control of nanocontainers with inhomogeneous surface charge patterns characteristic of pH values near the pKa of the charged surface moieties is discussed. Robustness of shape transitions is investigated by including the effects of ions via mean-field models and explicit-ion simulations.