Shape Memory\nSupramolecular Polymer Gels Constructed\nby Pillar[5]arene-Based Mechanically Interlocked Polymer Networks

Mechanically interlocked networks are cross-linked by\nmechanically\ninterlocked polymers, whose dynamic mechanical bonding provides a\nsolid foundation for their application in materials science. Noncovalent\ninteractions are indispensable linkages for building supramolecular\npolymers but exhibit low mechanical strength. Therefore, in this paper,\nwe have designed and synthesized a class of mechanically interlocked\nsupramolecular polymer networks (<b>MISPNs</b>) with shape memory\nbehavior, using which we have prepared gel materials with solvent-responsive\nshape memory behavior and reversible light transmittance changes in\nresponse to noncovalent interactions. It was found that the naphthalene-functionalized\npillar[5]arene (compound <b>3</b>) served as the backbone of\nthe <b>MISPNs</b>, and its mechanically interlocked topology\nnot only ensured good stability of the polymer networks but also endowed\nthe shape memory properties of the shape memory materials. Meanwhile,\nthe abundant oxygen (O) and sulfur (S) atoms in the polymer networks\nform multiple hydrogen bonds with the H atoms in the protonated solvent,\nwhich contributes to the shape memory behavior and the reversible\nlight transmission behavior of the gel materials. The herein reported <b>MISPNs</b> gel materials offer a possible strategy for the development\nof multifunctional materials with good mechanical properties, sensitive\nstimulus response properties, and excellent smart information protection\nproperties.