Cyclic poly(N-isopropylacrylamide)s containing an azobenzene mesogen (azo-c-PNIPAM) in the main chain were synthesized by a combination of reversible addition-fragmentation chain-transfer (RAFT) polymerization of NIPAM and subsequent alkyne-azide 'click' ring closure in a dilute DMF/water (1:1) solution via a modification of a previously reported protocol.1 The azobenzene mesogen was introduced into the main chain via an azobenzene-containing chain transfer agent in the RAFT polymerization. Interlocked azo-c-PNIPAM/cyclodextrin systems ([2]catenanes) were obtained when the ring closure was conducted in a solution containing a-cyclodextrin (a-CD). The structures of cyclic azo-PNIPAM and cyclic azo-PNIPAM with a locked a-cyclodextrin are depicted in Figure 1.The temperature-induced phase transition of azo-c-PNIPAM in water was investigated by a high-sensitivity differential scanning calorimetry, laser light scattering, and UV-Vis spectroscopy. Emphasis was placed on the effect of the azobenzene trans-cis photoisomerization and the azobenzene-cyclodextrin inclusion complex on the phase transition of azo-c-PNIPAM in water.References1. X.-P. Qiu, F. Tanaka, F. M. Winnik, Macromolecules 2007,   40, 7069-7071.

Cyclic poly(<i>N</i>-isopropylacrylamide)s containing an azobenzene mesogen inserted in the main chain

245th National Meeting (2013)

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Cyclic poly(N-isopropylacrylamide)s containing an azobenzene mesogen inserted in the main chain