Theoretical approaches to starlike polymer brushes in Θ-solvent

Abstract

Abstract A continuum-space mean-field model for brushes made of starlike polymers in Θ-solvent is developed. The model accounts for the segregation of molecules into two vertical layers and predicts the population fractions of these layers. It reproduces recently reported deviations of the brush heights from scaling theory at moderate and high grafting densities. In the regime of very low monomer densities, the scaling of its brush heights is crossing over to the classical scaling prediction. During our analysis, we modify the elastic properties of the molecules, as well as their volumetric interactions, in order to study the impact of these model parameters on the resulting brush properties. Comparisons with another, recently published mean-field model of brushes on a lattice and with molecular dynamic simulations are carried out. It is demonstrated that most variants of the mean-field models are generating brush heights in reasonable agreement with the simulation data. The partition of molecules into the two populations, however, exhibits a significant model dependence.