1H NMR study of temperature-induced phase separation in solutions of poly(N-isopropylmethacrylamide-co-acrylamide) copolymers
2010
Abstract
1H NMR spectroscopy was applied to investigate temperature-induced phase separation in solutions of poly(N-isopropylmethacrylamide-co-acrylamide) [P(IPMAm/AAm)] random copolymers in D2O, D2O/ethanol and D2O/acetone. For solutions of the copolymers with the AAm fraction not exceeding 16 mol% 1H NMR spectra show dynamic heterogeneity of copolymer chains in mesoglobules where AAm sequences and surrounding IPMAm sequences are hydrated and mobile, while other IPMAm sequences are dehydrated and their mobility is strongly reduced.
The obtained results are consistent with the idea that P(IPMAm/AAm) copolymer mesoglobules are rather porous and disordered.