Synthetic and biological gels undergo a sharp volume phase transition when subjected to a variety of environmental changes. Water and ion dynamics within swollen and compact phases are critical for understanding fundamental concepts in cellular (specifically neuronal) biophysics, for models of bound, free, or ordered water in complex environments; and for practical applications such as the design of gels for drug release, biomimetics, sensors, or actuators. In this work, we find, for the first time, basic physical parameters that shed light on the interaction of gels with water and electrolytes, across a volume phase transition. Water within a gel can be separated into bound and free populations with high exchange rate. We show that free water dynamics in compact gels are the same as those in pure water. Bound water was found to comprise a single layer around the polymers in both phases, with a correlation time three orders of magnitude higher than that of free water. Most importantly, salt-induced phase transition was found to be different from a standard coil-globule transition (e.g., temperature-induced), with no rejection of bound water as the gel compacts.
|Number of pages||9|
|Journal||Journal of Polymer Science, Part B: Polymer Physics|
|State||Published - 15 Nov 2015|
Bibliographical notePublisher Copyright:
© 2015 Wiley Periodicals, Inc.
- molecular dynamics
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Polymers and Plastics
- Materials Chemistry