Diblock Copolymer Brush-Based Adhesion Coupling Agents

Abstract

Traditional adhesion coupling agents based on small molecules often face challenges such as uneven interface distribution, sensitivity to humidity, and lack of energy dissipation in bulk adhesives, which limit both adhesion performance and long-term reliability. In this work, amphiphilic block copolymer brushes are presented as a new type of coupling agent to overcome these issues. The hydrophilic block forms stable, multi-site interactions with the substrate, while the hydrophobic block penetrates and entangles with the adhesive matrix, facilitating effective energy transmission and dissipation across a broader zone. For instance, before grafting amphiphilic block copolymer brushes, the adhesion strength between copper and polydimethylsiloxane is only 0.5 MPa, but after grafting, the adhesion strength is increased to 8.2 MPa, representing a 16.4-fold improvement, even in the absence of covalent bonding, and surpassing previous enhancement strategies. The adhesion remained strong under various harsh conditions, including thermal aging, thermal cycling, high temperature/high humidity, and even immersion in water. This adaptive approach, which allows for the customization of block compositions, offers great potential for a wide range of applications, including flexible electronics, microfluidics, coatings, and sealing technologies.