A quantitative theory for polyelectrolytes in salt-free dilute solutions is developed. Depending on the electrostatic interaction strength, polyelectrolytes in solutions can undergo strong stretching (with polyelectrolyte dimension R g ϳ l
We present first results of studies of the volume phase transition in poly(N-isopropylacrylamide) (NIPA) hydrogels by high-sensitive differential scanning calorimetry (HS−DSC). We examine
the behavior of the low-concentrated gels at different scanning rates and discuss the dependencies of the
transition parameters upon heating rate. It is shown that HS−DSC measurements at heating rate of
0.125 K/min provide results closely approximating the equilibrium ones in every respect except for the
value of transition temperature. At higher heating rates, the transition temperature appears to be
practically rate-independent, and network exhibits signs of spatially nonuniform structures developing
in the course of collapse, with some parts of the system collapsing under the restrictions of others being
almost unperturbed. The apparent enthalpy of this constrained transition is higher than that observed
at equilibrium. We discuss the hypothesis that the transition occurs through the spinodal decomposition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.