Aggregates of rod-coil diblock copolymers adsorbed at a surface

TL;DR

This paper investigates the behavior and stability of rod-coil diblock copolymer aggregates adsorbed on surfaces, focusing on their alignment, entropy effects, and decay profiles using extended scaling methods.

Contribution

It introduces a theoretical analysis of the adsorption and structural profiles of rod-coil diblock copolymer aggregates near surfaces, emphasizing entropy-driven shifts and stability.

Findings

Rod alignment maximizes energy gain in liquid crystalline structures.

Shift in rod positions decays with distance from the surface.

Profiles of decay are derived through free energy minimization.

Abstract

The behaviour of rod-coil diblock copolymers close to a surface is discussed by using extended scaling methods. The copolymers are immersed in selective solvent such that the rods are likely to aggregate to gain energy. The rods are assumed to align only parallel to each other, such that they gain a maximum energy by forming liquid crystalline structures. If an aggregate of these copolymers adsorbs with the rods parallel to the surface the rods shift with respect to each other to allow for the chains to gain entropy. It is shown that this shift decays with increasing distance from the surface. The profile of this decay away from the surface is calculated by minimisation of the total free energy of the system. The stability of such an adsorbed aggregate and other possible configurations are discussed as well.