Co-nonsolvency occurs if a mixture of two good solvents causes the collapse or demixing of polymers into a polymer-rich and solvent-rich phase in a certain range of compositions of these two solvents. The nonionic thermo-responsive polymer, poly(N-isopropylmethacrylamide) (PNIPMAM), which features a lower critical solution temperature in aqueous solution, is known to show a collapse transition in a mixture of two competing good solvents. the co-nonsolvency response of its block copolymer containing zwitterionic poly(sulfobetaine)s, especially poly(4-((3-methacrylamidopropyl)dimethylammonio)butane-1-sulfonate)) (PSBP)，which exhibits an upper critical solution temperature and shows a strong swelling in aqueous media, is newly studied. We focus on the co-nonsolvency behavior of PSBP-<i>b</i>-PNIPMAM thin films in water/acetone mixtures using in situ time-of-flight neutron reflectometry (TOF-NR) and spectral reflectance (SR). Furthermore, Fourier transform infra-red (FTIR) spectroscopy is applied to investigate the interaction between the polymer thin film and water/co-solvent, which strongly alters dependend on their deuteration level.

Investigation of co-nonsolvency phase transition of poly(sulfobetaine)-based diblock copolymer thin films

ACS Spring Meeting 2021

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