Formation and Equilibrium Properties of Living Polymer Brushes

TL;DR

This study uses Monte Carlo simulations to analyze the properties of living polymer brushes, revealing power-law behaviors in chain length, orientation, and force, with a focus on molecular weight distribution and density profiles.

Contribution

It introduces a detailed Monte Carlo model for living polymer brushes and characterizes their structural and force properties, highlighting power-law dependencies and distribution behaviors.

Findings

Molecular weight distribution decays slowly compared to bulk systems.

Density profiles fit power-law behaviors with self-consistent exponents.

Force exerted by the brush also follows a power-law dependence.

Abstract

Polydisperse brushes obtained by reversible radical chain polymerization reaction onto a solid substrate with surface-attached initiators, are studied by means of an off-lattice Monte Carlo algorithm of living polymers (LP). Various properties of such brushes, like the average chain length and the conformational orientation of the polymers, or the force exerted by the brush on the opposite container wall, reveal power-law dependence on the relevant parameters. The observed molecular weight distribution (MWD) of the grafted LP decays much more slowly than the corresponding LP bulk system due to the gradient of the monomer density within the dense pseudo-brush which favors longer chains. Both MWD and the density profiles of grafted polymers and chain ends are well fitted by effective power laws whereby the different exponents turn out to be mutually self-consistent for a pseudo-brush in the strong-stretching regime.