Bunkin, N FShkirin, Alexey VKozlov, ValeriyNinham, BarryUspenskaya, Elena VGudkov, Sergey2020-06-222020-06-220021-9606http://hdl.handle.net/1885/205430The swelling of a polymer ion-exchange membrane Nafion in water with various heavy isotope contents (D2O) was studied by photoluminescent UV spectroscopy. The photoluminescence arises because of the presence of sulfonic groups attached to the ends of the perfluorovinyl ether groups that form the tetrafluoroethylene (Teflon) backbone of Nafion. The width of the colloidal region, which is formed near the membrane surface as a result of the outgrowth of Nafion microfibers toward the bulk liquid, varies non-monotonically with D2O content, displaying a narrow maximum in the low concentration region. A significant insight into the unexpected isotopic effects revealed in swelling Nafion in deuterated water is provided. Mainly, the polymer swelling is very sensitive to small changes (on the order of several tens of parts per million) in the content of deuterium, which, for instance, can help in understanding the isotopic effects in living tissues.This study was supported by a Grant from the President of the Russian Federation for young scientists (Grant No MD-3811.2018.11), the Russian Foundation for Basic Research, Grant No. 17-02-00214, the R&D program (No. AAAA-A18-118021390190-1), and the MEPhI Academic Excellence Project (Contract No. 02.a03.21.0005).application/pdfen-AU© 2018201810.1063/1.50420652020-01-19