Soft Acrylic Graft Copolymer as Clear Viscoelastic Films for Flexible Displays

Clear viscoelastic films (CVFs) are essential adhesive components in flexible displays, requiring a precise balance of softness, adhesion, elasticity, and optical clarity. In this study, well-defined polyacrylate graft copolymers were synthesized via atom transfer radical polymerization (ATRP) of poly(butyl acrylate) (pBA) macromonomers, followed by copolymerization with acrylate monomers to produce high-performance CVFs. By careful control of graft molecular weight and composition, the resulting CVFs exhibit an excellent balance of mechanical compliance, strong interfacial adhesion, high optical clarity, and good thermal stability. Notably, Graft-50(−15%) showed a low glass transition temperature (−39.0 °C), a low storage modulus (∼30 kPa), a high peel force (7.9 N), excellent strain recovery (93.43%), and sufficient stress relaxation (64.30%). It retained structural integrity after 200,000 folding cycles, demonstrating outstanding mechanical durability. These findings provide a molecular design approach for developing high-performance CVFs and present promising solutions for the advancement of flexible displays.