Solvent-free stretchable photo-responsive supramolecular actuator topologically cross-linked by azobenzene-cyclodextrin based slide-ring system

The highly reversible photo-isomerization speed and efficiency of azobenzene make photomechanical polymers come true. While how to amplify the impact of molecular photo-isomerization upon the polymers to realize macro-motions remains a long way. Here we prepared a multi-stimuli-responsive supramolecular actuator via introducing slide-ring cross-linkers of azobenzene-cyclodextrin into polyacrylamide network. The result gel showed extremely quick response to various stimuli especially light even without solvent. Attributing to the slide-ring crosslinkers in the structure, the bending angle of CD-Azo gel reached to 40.0°within 0.5 s toward 365 nm light resource. In addition, overcoming the mechanical weakness of stimuli-sensitive hydrogel, the solvent-free polymer film exhibited high tensile strength of 15.00 MPa, elongation at breaking limit of 150% and Young's modulus of 0.34 MPa.