"On-demand" control of thermoresponsive properties of poly(N-isopropylacrylamide) with cucurbit[8]uril host-guest complexes.

The chain end complexation of a functional PNIPAM by a cucurbit[8]uril-viologen complex causes a shift in its lower critical solution temperature (LCST) by over 5 °C. An instantaneous phase change of the thermally responsive polymer beyond its LCST can be induced by addition of the aqueous cucurbituril host-guest complex. Subsequent decomplexation upon addition of a competitive guest releases the PNIPAM terminus and triggers complete reversibility.