Volume phase transition of polymer gel in water and heavy water

Deuterium Isotope Effect on the Phase Separation of Zipper-Type Hydrogen-Bonding Inter-Polymer Complexes in Solution

“…This enormous deuterium isotope effect in aqueous PAA-PAAM solution has not been observed for other aqueous macromolecular systems, such as poly(N-isopropylacrylamide), [13,14,16] cellulose, [20,21] polypeptides, [22] and proteins [23,24] (about 1 -2 8C in these systems). Since inter-macromolecular hydrogen bonds play a more significant role for the phase transition of a zipper-type macromolecular system than for the other aqueous macromolecular systems, it is plausible to observe such a huge isotope effect for the macromolecular system investigated here.…”

Transient analysis of temperature-sensitive neutral hydrogels

“…where wðT; fÞ is the polymer-solvent interaction parameter, defined as (Shirota et al, 1998;Hirotsu, 1991) wðT; fÞ ¼ À Ds…”

Deuterium isotope effects on swelling-shrinking states of polymer gels in aqueous solutions:Fluorescence study

“…Furthermore, the swelling ratios of the shrunken PNIPAM gel in pure water and pure heavy water were the same within experimental error. [5,6] These results mean that the hydrophobic interactions in hydrogel are insensitive to the isotopic substitutions on the hydroxyl and amide groups which form hydrogen bonds, even though it is possible that hydrogen bonds form between polymer chains.…”

“…[5][6][7] From the simulation based on a modified Flory-Rehner model proposed by Shibayama et al, [8] it became clear that the deuterium isotope effect on the swelling-shrinking curve of PNIPAM gel mainly arises from the enthalpy per monomer unit of the polymer network related to the volume phase transition. [5] By using a fluorophore that is sensitive to the polarity of the medium, the deuterium isotope effects of the microenvironments in the volume phase transition of PNIPAM gel and the phase separation of linear PNIPAM were also observed. [6] The features of the microenvironment change and the bulk change near the transition region were not identical.…”