Effect of interfacial curvature on the adsorption of copolymer stabilized nanoparticles of different copolymer compositions: a Brownian Dynamics study.
Block copolymer-stabilized nanoparticles placed in the presence of a curved oil-water interface are described using Brownian Dynamics simulations. These simulations are targeted towards an exploration of the effect of geometry of the oil-water interface on the adsorption of the stabilized nanoparticle, and this goal is achieved by the systematic variation of the interfacial curvature, while exploring different block copolymer compositions. The contact angle, the order parameter and polymer density across the interface are used to assess the effect of a given block copolymer composition on the adsorption at the liquid-liquid interface. We find that the contact angle for a block-copolymer stabilized nanoparticle is affected by the curvature of the oil-water interface. This is a departure from earlier results of Komura et al. [J. Chem. Phys. 2006, 124, 241104], where the contact angle of a solid particle at a curved interface obeys the Young's formula for contact angle, in which case it is independent of the interfacial curvature. A part of the change of contact angle results from the increase of the radius of gyration of the nanoparticle due to the presence of the block copolymer. Furthermore, an investigation of the structure of the block copolymer and its distribution across the interface reveals changes as the curvature of the interface is changed, and those changes are reflected in different contact angle values.
Almusallam
Abdulwahab S
AS
Department of Chemical Engineering, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait. abdulwahab.almusallam@ku.edu.kw