Abstract Polymeric gels, when made into thin films, are reported to depict a reversible folding behavior on exposure to favorable solvents as a result of the coupled diffusion–deformation mechanism. In this work, we develop a model based on the coupled diffusion–deformation mechanism which can predict the large deformation caused during this reversible folding behavior of a polymeric thin film. The formulation incorporates a concentration dependent Young’s modulus variation. It is found that the incorporation of concentration dependent Young’s modulus of the film in the formulation is essential to predict the folding curvatures accurately. The results obtained using this model are validated with the experimental results of the Chitosan–Water system by comparing the folding characteristics — intermediate folding stages and curvature, while accurately explaining the mechanism of reversible folding. The model is applied to other material systems such as PVA–Water and PDMS–Hexane systems. Furthermore, we demonstrate that the developed model successfully predicts the buckling and wrinkling phenomenon observed experimentally in stimuli-responsive polymer thin films.

中文翻译：

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刺激响应聚合物薄膜的耦合扩散变形行为

摘要 据报道，当聚合物凝胶制成薄膜时，由于扩散-变形耦合机制，它在暴露于有利溶剂时表现出可逆折叠行为。在这项工作中，我们开发了一个基于耦合扩散变形机制的模型，该模型可以预测聚合物薄膜可逆折叠行为期间引起的大变形。该配方结合了依赖于浓度的杨氏模量变化。发现在配方中加入依赖于浓度的薄膜杨氏模量对于准确预测折叠曲率是必不可少的。通过比较折叠特性——中间折叠阶段和曲率，使用该模型获得的结果与壳聚糖-水系统的实验结果进行了验证，同时准确解释可逆折叠的机理。该模型适用于其他材料系统，如 PVA-水和 PDMS-己烷系统。此外，我们证明开发的模型成功地预测了在刺激响应聚合物薄膜中实验观察到的屈曲和起皱现象。