Invited: Dynamic Pressure-Sensitive Adhesion in Liquid Crystal Elastomers

Nematic liquid crystal elastomers (LCEs) are known for their exceptional viscoelastic dissipation and energy-damping properties, which are believed to contribute to their unusually strong pressure-sensitive adhesion (PSA). In this study, we explore the mechanism behind this enhanced PSA by fabricating thin adhesive tapes with LCEs of different chemical formulations, analyzing their material and surface properties, and evaluating their adhesion performance through standard tests, including 90-degree peel, lap shear, and probe tack tests. Our results confirm that the LCE adhesive exhibits high adhesion strength and tackiness in the nematic phase while showing low adhesion strength and tackiness in the isotropic phase. Furthermore, we demonstrate that by modifying the LCE polymer network architecture, it is possible to fine-tune the viscoelastic properties to meet the Dahlquist Criterion for ideal PSA, which requires a glass transition temperature around 0°C and a shear modulus of approximately 0.1 MPa at room temperature.