Shape Memory Vitrimer for Reversible Dry Adhesion Enabled by Multiscale Reprocessing and Shape Fixing

Existing shape memory polymer based dry adhesives lack the ability to be reprocessed and thus to form multiple permanent shapes, limiting their adaptability to various arbitrary surfaces. Here, we present a shape memory vitrimer (SMV) based reversible dry adhesive that is reprocessable, relying on transesterification. The SMV possesses a glass transition temperature (Tg) of ∼50 °C and a topology freezing transition temperature (Tv) of ∼100 °C and exhibits a significant drop in storage modulus across Tg and stress relaxation above Tv. Combined with surface microstructuring, these characteristics provide our SMV dry adhesive with excellent adhesion strength (∼1.75 MPa) and reversibility (∼1000) due to the shape memory effect. Such an outstanding adhesive capability is further highlighted by reprocessing the SMV dry adhesive, thus reforming its permanent shape to adapt to an arbitrary adherend shape. Moreover, the SMV can self-weld above Tv, enabling easy repairs and enhancing its versatility for dry adhesive applications.