6533b826fe1ef96bd1284769

RESEARCH PRODUCT

Self-assembly of semiflexible polymers confined to thin spherical shells

Mihir R. KhadilkarArash Nikoubashman

subject

Models Molecularchemistry.chemical_classificationPersistence lengthMaterials scienceCondensed matter physicsPolymersMolecular Conformation02 engineering and technologyGeneral ChemistryPolymer021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesSpherical shellTopological defectCondensed Matter::Soft Condensed MatterMolecular dynamicschemistryLiquid crystal0103 physical sciencesMonolayerSoft matter010306 general physics0210 nano-technologyMechanical Phenomena

description

Confinement effects are critical for stiff macromolecules in biological cells, vesicles, and other systems in soft matter. For these molecules, the competition between the packing entropy and the enthalpic cost of bending is further shaped by strong confinement effects. Through coarse-grained molecular dynamics simulations, we explore the self-assembly of semiflexible polymers confined in thin spherical shells for various chain lengths, chain stiffnesses, and shell thicknesses. Here, we focus on the case where the contour and persistence length of the polymers are comparable to the radius of the confining cavity. The range of ordered structures is analyzed using several order parameters to elucidate the nature of orientational ordering in different parameter regimes. Previous simulations have revealed the emergence of bipolar and quadrupolar topological defects on the surface when the entire cavity was filled with a concentrated polymer solution [Phys. Rev. Lett., 2017, 118, 217803]. In contrast, spherical shell confinement restricts the appearance of a bipolar order. Instead, only the extent of the quadrupolar order changes with chain stiffness, as evidenced by the relative motion of topological defects. In the case of monolayers, we observe a nematic to smectic transition accompanied by a change in the nematic grain-size distribution as the contour length was decreased.

https://doi.org/10.1039/c8sm01170b