Ionic comonomer effect of poly(N-isopropylacrylamide) copolymer containing D-π-A type pyran-based fluorescent dye.

Temperature and pH responsive poly(N-isopropylacrylamide) (poly(NIPAM)) copolymer containing D-π-A type pyran-based fluorescent dye (fluorophore) and basic comonomer, N-[3-(dimethylamino)propyl]-methacrylamide (DMAPAM) was prepared by free radical polymerization. With increase of pH values, aqueous poly(NIPAM-co-DMAPAM-co-fluorophore) solution showed decrease of a lower critical solution temperature (LCST) and increase of fluorescence intensity, due to a change in the ionization state. And also hydrodynamic radius of poly(NIPAM-co-DMAPAM-co-fluorophore) changed correspondingly to changes of temperature and pH values.