Light-Activated\nAdhesion and Debonding of Underwater\nPressure-Sensitive Adhesives

Abstract

Pressure-sensitive\nadhesives (PSAs) such as sticky notes and labels\nare a ubiquitous part of modern society. PSAs with a wide range of\npeel adhesion strength are designed by tailoring the bulk and surface\nproperties of the adhesive. However, designing an adhesive with strong\ninitial adhesion but showing an on-demand decrease in adhesion has\nbeen an enduring challenge in the design of PSAs. To address this\nchallenge, we designed alkoxyphenacyl-based polyurethane (APPU) PSAs\nthat show a photoactivated increase and decrease in peel strength.\nWith increasing time of light exposure, the failure mode of our PSAs\nshifted from cohesive to adhesive failure, providing residue-free\nremoval with up to 83% decrease in peel strength. The APPU-PSAs also\nadhere to substrates submerged underwater and show a similar photoinduced\ndecrease in adhesion strength.