Concave polymer brushes inwardly grafted in spherical cavities

Abstract

The structure and scaling properties of inwardly curved polymer brushes, tetheredunder good solvent conditions to the inner surface of spherical shells like membranesand vesicles, are studied by extensive Molecular Dynamics simulations and comparedwith earlier scaling and Self-Consistent Field Theory (SCFT) predictions for differentmolecular weight of the polymer chains N and grafting density σ g in the case of strongsurface curvature, R−1 . We examine the variation of the critical radius R ∗ (σg ), sepa-rating the regimes of weak concave brushes and compressed brushes, predicted earlierby Manghi et al. [Eur. Phys. J. E 5, 519 (2001)] as well as various structural proper-ties as the radial monomer- and chain-end density profiles, orientation of bonds, brushthickness, etc. The impact of chain stiffness, κ, on concave brush conformations isbriefly considered too. Eventually we present the radial profiles of local pressure nor-mal, PN , and tangential, PT , to the grafting shell, the surface tension, γ(σg ), for softand semi-rigid brushes, and find a new scaling relationship PN(R) ∝ σg4 , independentof the degree of chain stiffness.

Pressure Anisotropy in Polymer Brushes and Its Effects on Wetting

“…Badr et al “choose to evaluate only the integral over the peaks at the interfaces”. Similarly, Milchev and Petkov noted negative interfacial tensions that grow in absolute value with increasing grafting density in concave polymer brushes. Léonforte and Müller extracted interfacial tensions from the thermal fluctuation spectrum of the brush–vapor interface, reporting good agreement with the surface tensions of their nongrafted counterparts.…”