Boosting the photo-switchability of double-responsive water-soluble polymers by incorporating arylazopyrazole dyes

Dual thermo- and light-responsive water-soluble copolymers that respond to exclusively non-invasive triggers are obtained by functionalising poly(N,N-dimethylacrylamide) with arylazopyrazole side chains. The light-induced E-Z (trans-Z) photo isomerisation of these dyes provides an exceptionally effective photo-switch, which can reversibly shift the LCST-type phase transition temperatures by almost 25 K. The incorporation of an arylazopyrazole (AAP) dye into water-soluble poly(N,N-dimethylacrylamide) polymers enables an outstandingly large photo-modulation of the coil-to-globule LCST-type phase transition temperature.