Polyurethane diacrylate incorporated pressure-sensitive adhesives with enhanced strain recovery†

Pressure-sensitive adhesives (PSAs) are used in a wide range of applications, including electronics, automobiles, healthcare, and packaging, due to their excellent bonding affinity with minimal applied pressure without the need for solvents, heat, or additional processing. Although they exhibit excellent usability with high adhesion strength, PSAs must overcome the limitation of delamination caused by poor strain recovery to be applied to flexible electronics. In this study, we achieved rapid strain recovery in PSAs by utilizing polyurethane diacrylate (PUDA) as a crosslinker. The fabricated PSA demonstrated a significantly faster strain recovery time (∼2.5 s) compared to the conventional crosslinked 1,6-hexanediol diacrylate (HDDA) PSA (∼61.0 s). Notably, the PUDA PSA also exhibited outstanding 180° peel strength (∼22.0 N per 25 mm), surpassing that of a commercial PSA (∼12.3 N per 25 mm). The fabricated PSAs showed promise for applications under harsh straining conditions confirmed through 100 strain-recovery cycles at 20% tensile strain. This study directs the way to improve PSA's poor strain recovery properties and paves the way for the future advancement direction in adhesive technology.