Nonequilibrium Phase Separation‑driven Temporally Tunable Optical Response in Thermoresponsive Hydrogels

ZHANG Man-man; WANG Chi-yu; WANG Hui-juan; FAN Wen-hao; YE Zi-fan; GAO Shao-xuan; MENG Xian-rui; PENG Chuang; ZHANG Wen-kai

doi:10.14028/j.cnki.1003-3726.2026.26.054

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Nonequilibrium Phase Separation‑driven Temporally Tunable Optical Response in Thermoresponsive Hydrogels

更新时间：2026-07-06

- Nonequilibrium Phase Separation‑driven Temporally Tunable Optical Response in Thermoresponsive Hydrogels
  增强出版
- Polymer Bulletin Vol. 39, Issue 7, Pages: 1204-1215(2026)
- 作者机构：
  
  河南大学化学与分子科学学院　开封 475004
- 作者简介：
- 基金信息：
- DOI：10.14028/j.cnki.1003-3726.2026.26.054
  CLC：
- Received：25 March 2026，
  
  Accepted：10 April 2026，
  
  Online First：08 June 2026，
  
  Published：20 July 2026
- 稿件说明：
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张曼曼, 王驰宇, 王慧娟, 樊文豪, 叶子凡, 高稍轩, 孟献瑞, 彭闯, 张文凯. 非平衡相分离驱动的温敏水凝胶时间可调光学响应. 高分子通报, 2026, 39(7), 1204–1215.

Zhang, M. M.; Wang, C. Y.; Wang, H. J.; Fan, W. H.; Ye, Z. F.; Gao, S. X.; Meng, X. R.; Peng, C.; Zhang, W. K. Nonequilibrium phase separation‑driven temporally tunable optical response in thermoresponsive hydrogels. Polym. Bull. (in Chinese), 2026, 39(7), 1204–1215.
张曼曼, 王驰宇, 王慧娟, 樊文豪, 叶子凡, 高稍轩, 孟献瑞, 彭闯, 张文凯. 非平衡相分离驱动的温敏水凝胶时间可调光学响应. 高分子通报, 2026, 39(7), 1204–1215. DOI： 10.14028/j.cnki.1003-3726.2026.26.054.

Zhang, M. M.; Wang, C. Y.; Wang, H. J.; Fan, W. H.; Ye, Z. F.; Gao, S. X.; Meng, X. R.; Peng, C.; Zhang, W. K. Nonequilibrium phase separation‑driven temporally tunable optical response in thermoresponsive hydrogels. Polym. Bull. (in Chinese), 2026, 39(7), 1204–1215. DOI： 10.14028/j.cnki.1003-3726.2026.26.054.

摘要

温敏水凝胶的光学响应通常由平衡相行为决定，而对溶剂交换过程中产生的非平衡效应仍缺乏系统性的认识。本研究以P(NIPAM-

-AAm)水凝胶为模型体系，考察其在水–乙醇混合溶剂中的透光率随时间的变化行为。在相同终态温度与溶剂组成条件下，不同处理方式得到的光学状态存在明显差异。水溶胀态样品直接进入高温乙醇环境时，乙醇向内扩散在凝胶内部形成瞬时组成梯度，使局部区域进入LCST敏感区间并发生相分离，出现短时浑浊；而先完成溶剂交换再升温时，体系始终处于均一溶剂环境，保持透明。通过分析透光率–时间曲线，提取相分离时间

与恢复时间

rel

，发现两者随乙醇浓度显著变化，其比值由约11.7降低至1.5，对应由长时间维持浑浊到快速恢复透明的转变。冷冻干燥扫描电子显微镜与原位光学显微结果表明，不同处理路径对应的结构形貌存在明显差异。通过调控乙醇浓度或环境温度，可在数十秒至数千秒范围内连续调节相分离特征时间，实现对光学响应时间的精准控制，为动态光学调控材料的设计提供了可行思路。

Abstract

The optical response of thermoresponsive hydrogels is typically governed by equilibrium phase behavior

whereas the nonequilibrium effects arising from solvent exchange processes remain insufficiently understood. In this study

we used P(NIPAM-

-AAm) hydrogels as a model system to investigate the temporal evolution of transmittance in water-ethanol mixed solvents. Under identical final-state temperatures and solvent compositions

distinct optical states were observed depending on the treatment pathway. When a water-swollen sample is directly introduced i

nto a high-temperature ethanol environment

the inward diffusion of ethanol generates transient compositional gradients within the gel

causing localized regions to enter the LCST-sensitive range and undergo phase separation

resulting in temporary turbidity. In contrast

when solvent exchange was completed prior to heating

the system remained in a homogeneous solvent environment and remained transparent. Analysis of the transmittance-time curves revealed the characteristic phase separation time

and recovery time

rel

both of which varied significantly with ethanol concentration

with their ratio decreasing from approximately 11.7 to 1.5

corresponding to a transition from prolonged turbidity to rapid recovery of transparency. Cryo-SEM and

in situ

optical microscopy results revealed distinct structural morphologies depending on the treatment pathway. The phase separation characteristic time can be continuously tuned from tens to thousands of seconds by varying the ethanol concentration or temperature

allowing precise regulation of the optical response time and offering a promising strategy for dynamic optical materials.

关键词

Keywords

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