Photoregulated Sol‐Gel Transition of Novel Azobenzene‐Functionalized Hydroxypropyl Methylcellulose and Its <i>α</i>‐Cyclodextrin Complexes

Abstract

Abstract Summary: Novel azobenzene‐functionalized hydroxypropyl methylcellulose (AZO‐HPMC) polymers and their α ‐cyclodextrin ( α ‐CD) complexes have been prepared. These polymers show interesting sol‐gel transition behavior in aqueous solutions. In the absence of α ‐CD, the gelation temperature increases after UV irradiation, while in the presence of α ‐CD, the gelation temperature decreases after UV irradiation. The difference in the gelation temperatures between the trans and cis samples of AZO‐HPMC opens a wide operating window for reversible regulation of the sol‐gel transition behavior by photoirradiation. The UV‐induced cis / trans isomerism of azobenzene‐functionalized hydroxypropyl methylcellulose and its α ‐cyclodextrin complexes. image The UV‐induced cis / trans isomerism of azobenzene‐functionalized hydroxypropyl methylcellulose and its α ‐cyclodextrin complexes.