Multiblock copolymer solutions in contact with a surface: self-assembly, adsorption, and percolation

Area of Science:

• Polymer Science
• Surface Chemistry
• Computational Materials Science

Background:

• Amphiphilic copolymers act as compatibilizers and stabilizers in solutions and at surfaces.
• Multiblock copolymers exhibit unique behaviors due to block connectivity and antagonistic properties.

Purpose of the Study:

• Investigate the behavior of amphiphilic multiblock copolymer solutions near attractive surfaces.
• Understand the influence of solvent quality and surface attraction on copolymer self-assembly.

Main Methods:

• Lattice Monte Carlo simulations were employed to model copolymer behavior.
• Systems with a large number of blocks and low solvophobic monomer fraction were studied.
• Surface interactions ranged from noninteracting to strongly attractive for solvophobic monomers.

Main Results:

• Bulk micelles form irrespective of the surface, with similar size and shape.
• Increasing surface attraction leads to solvophobic monomer adsorption, forming surface micelles above a threshold.
• Surface micelles organize, percolate, and form a concentrated layer, remaining in equilibrium with bulk micelles.

Conclusions:

• Attractive surfaces induce surface micelle formation and organization in amphiphilic multiblock copolymers.
• Two distinct timescales govern self-assembly and bulk-to-surface transfer.
• The findings are relevant for designing surface-active polymeric materials.