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Research
2021

2021.11.30

Temperature dependence of polymer network diffusion

Authors
Takeshi Fujiyabu, Takamasa Sakai, Ryota Kudo, Yuki Yoshikawa, Takuya Katashima, Ung-il Chung, and Naoyuki Sakumichi

Abstract
The swelling dynamics of polymer gels are characterized by the (collective) diffusion coefficient $D$ of the polymer network. Here, we measure the temperature dependence of $D$ of polymer gels with controlled homogeneous network structures using dynamic light scattering. An evaluation of the diffusion coefficient at the gelation point ${Dgel} and the increase therein as the gelation proceeds Δ D \equiv D - D_{g e l} indicates that Δ D is a linear function of the absolute temperature with a significantly large negative constant term. This feature is formally identical to the recently discovered "negative energy elasticity’’ [Phys. Rev. X 11, 011045 (2021)], demonstrating a nontrivial similarity between the statics and dynamics of polymer networks. Physical Review Letters : https://journals.aps.org/prl/accepted/1e07bY75S661258cf6495802dd3daac1c85b89a84$

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