考虑微观变形特征的水凝胶均匀和非均匀溶胀分析及其影响参数研究

刘岩; 王惠明

doi:10.6052/0459-1879-20-368

考虑微观变形特征的水凝胶均匀和非均匀溶胀分析及其影响参数研究

doi: 10.6052/0459-1879-20-368

刘岩^*,
王惠明^*,†,2), ,

^*浙江大学工程力学系, 杭州 310027
^†浙江省软体机器人与智能器件研究重点实验室, 杭州 310027

基金项目: 1) 国家自然科学基金资助项目(11772296)

详细信息

作者简介:
2) 王惠明, 教授, 主要研究方向: 多场耦合力学,智能软材料非线性力学. E-mail: wanghuiming@zju.edu.cn

通讯作者:
王惠明

中图分类号: O343.5
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出版历程
- 收稿日期: 2020-10-23
- 刊出日期: 2021-02-10

HOMOGENEOUS AND INHOMOGENEOUS SWELLING AND PARAMETRIC STUDY OF HYDROGELS CONSIDERING THE MICROSTRUCTURAL DEFORMATION

Liu Yan^*,
Wang Huiming^{*,†,2)
, ,}

^*Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
^†Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou 310027, China

摘要

摘要: 本文给出考虑微观变形的水凝胶溶胀的分析模型,该模型假设构成聚合物网络的单链受到由于周围链的作用而产生类似圆管状的约束,并且认为每个单链变形与网络变形之间存在非仿射关系.利用该模型分析了凝胶在自由溶胀情形,预拉伸凝胶单一方向溶胀情形以及具有刚性核的球形凝胶溶胀至平衡状态情形的变形特征.研究表明, 对于自由溶胀的均匀变形情形, 水凝胶微观单链与宏观网络的变形相一致,伸长率随链段数的增加而增大, 随单链密度的增大而减小.伸长率也会随有效圆管几何参数数值的增大而增大,但是当外部溶剂压力达到一定数值以后单链的圆管约束对凝胶溶胀变形影响逐渐减小.在单一方向溶胀状态下,预拉伸凝胶会出现微观单链和宏观网络伸长率相等的溶胀平衡状态,此时约束应力等于零.具有刚性核的球形凝胶溶胀至平衡状态时产生径向和环向伸长率不相等的非均匀球对称变形.在刚性核的附近, 单链和网络的径向伸长率均大于自由溶胀状态伸长率.在远离刚性核的位置, 单链和网络的伸长率均接近自由溶胀状态的伸长率.网络渗透压随有效圆管几何参数数值的增大而降低,溶剂分子体积分数则随有效圆管几何参数数值的增大而增大.所建立的分析模型可以模拟凝胶溶胀导致的微观单链变形.
- 水凝胶 /
- 均匀溶胀 /
- 非均匀溶胀 /
- 非仿射 /
- 微观变形
Abstract: An analytical model is proposed to analyze the swelling-induced deformation of the hydrogels considering the microstructural deformation of the polymer chains. It is assumed that the chain is constrained to a tube-like space due to the action of the surrounding chains, and the chains experience the non-affine deformation. Based on the presented model, we studied the free swelling deformation, the swelling along one direction with the pre-stretches in other two directions and the constraint swelling of a spherical hydrogel with a rigid core. For the free swelling case, the deformation is homogeneous and the deformation of the network is equal to that of the chains. The stretches of the network and the chains increase with the increase of the number of polymer segments and decrease with the increase of the density of the chains. The stretches also increase with the increase of the effective tube geometry parameter (ETGP). The effect of the ETGP on the swelling-induced stretch gradually disappears when the external solvent pressure exceeds a certain value. For the swelling along one direction with pre-stretches in other two directions, the equilibrium state with which the stretch of micro-chain equals to that of macro-network can be reached. At this state, the stresses in the hydrogel become zero. For the constraint swelling of a spherical hydrogel with a rigid core, the hydrogel deforms inhomogeneously and the swelling-induced radial stretch is different from the tangential stretch. At the region near the rigid core, the stretch of micro-chain and the stretch of macro-network in the radial direction are larger than that of the free swelling state. At the region far from the rigid core, the stretch of the micro-chain and the radial and tangential stretches of the macro-network approach to that of the free swelling state. The osmotic pressure decreases with the increase of the ETGP, while the volume fraction of the solvent molecules increases with the increase of the ETGP. The presented model can be used to predict the swelling-induced deformation of micro-chain.
- hydrogel /
- homogeneous swelling /
- inhomogeneous swelling /
- non-affine /
- microstructural deformation

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