Harnessing Extreme Dynamic Soft Elasticity in Liquid Crystal Elastomers with Slidable Crosslinks for Pressure-Sensitive Adhesives

Liquid crystal elastomers (LCEs) exhibit exceptional energy dissipation compared to amorphous elastomers due to their dynamic soft elasticity. In this study, we develop a new class of LCEs incorporating polyrotaxane (PRx-LCEs) as slidable crosslinkers. Surprisingly, PRx-LCE displays much enhanced energy dissipation, surpassing even glass transition (T_g), as evidenced by the tan delta curve in viscoelastic measurements. Such unprecedented high energy dissipation ability together with enhanced stress-relaxation observed in PRx-LCE leads to superior adhesion in both probe tack and peel tests, outperforming conventional LCEs and commercial adhesives. In addition, PRx-LCE demonstrates temperature responsive adhesion, facilitating residue-free removal at elevated temperatures. The synergy between LCE and slidable crosslinks enables the development of robust and switchable pressure-sensitive adhesives with versatile applications.