Cleanly Removable and Degradable Bio-Based Adhesive for Flexible Displays

Abstract

In advanced applications such as flexible displays, reusing components is essential for achieving sustainability. However, the removal of acrylic pressure-sensitive adhesives (PSAs), which bond these components, remains a major challenge due to residue formation and the non-degradable C─C backbone. Here, the development of new acrylic PSA alternatives for foldable displays is reported by introducing ultraviolet (UV)-triggered debondability, degradability through lipoic acid analogs, and a visible-light-curing process. PSAs composed of 60 mol% lipoic acid ethyl ester (LpEt) and 3 mol% UV-cross-linkable benzophenone-functionalized acrylic monomers exhibit viscoelastic properties comparable to those of conventional acrylic PSAs, while also enable clean removal from substrates after use. Following removal, the PSAs efficiently degrade into small molecular units in the presence of a green reductant or can be recovered as monomers under controlled conditions. This strategy offers a promising pathway toward sustainable PSAs, enables the recycling of valuable substrates from flexible display modules while simultaneously allows adhesive recovery, thus presents a viable alternative to conventional acrylic adhesives.