Abstract

Poly(N-vinylcaprolactam), PNVCL, chains undergo a temperature-induced, reversible and endothermic collapse in water at around 32 °C. The entropy gain driving PNVCL collapse has to come from water molecules, but it cannot be associated with their passage from the polymer hydration shell to the bulk because there is no difference in their tetrahedral structural order. I have shown that the water entropy gain comes from the decrease in solvent-excluded volume effect associated with chain collapse: there is a marked increase in the spatial configurations accessible to water molecules, leading to a large gain in their translational entropy. This mechanism, even though generic, proves to be effective solely in water and aqueous solutions because the magnitude of the solvent-excluded volume effect is amplified by the large number density of water, stemming from the strength of H-bonds and the small size of water molecules.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.