Photo-responsive supramolecular polymer based on a CB[5] analogue

A supramolecular polymer was constructed in aqueous solution via the intermolecular recognition between a cucurbit[5]uril-like macrocycle (Me10TD[5]) and trans-4,4′-bis(aminomethyl)azobenzene dihydrochloride, whose binding behaviors were confirmed by proton nuclear magnetic resonance (1H NMR), isothermal titration calorimetry (ITC) and electrospray ionization mass spectrometry (ESI-MS) experiments. The resulting polymer exhibited bending/extending behaviors under alternative UV light irradiations due to the trans/cis isomerization of the azobenzene group. The photo-responsive performance of the polymer was investigated by UV–Vis, transmission electron microscopy (TEM), and dynamic light scattering (DLS) measurements.