Linear elasticity of polymer gels in terms of negative energy elasticity
Linear elasticity of polymer gels in terms of negative energy elasticity
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DOI：
10.1038/s41428-021-00529-4
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发表时间：
2021-03
期刊：
影响因子：
2.8
通讯作者：
N. Sakumichi;Yuki Yoshikawa;T. Sakai
中科院分区：
文献类型：
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作者：
N. Sakumichi;Yuki Yoshikawa;T. Sakai
我们最近发现，在制备状态下的聚合物凝胶的线性弹性的能量贡献可以是一个显着的负值;剪切模量是不成比例的绝对温度。我们的发现挑战了传统的概念，即聚合物凝胶弹性主要是由熵贡献。现有的经典橡胶弹性理论的分子模型，包括仿射，幻影，和连接仿射网络模型，不能用来估计聚合物凝胶的结构参数。在这篇重点综述中，我们总结了在制备状态下使用四臂聚乙二醇（PEG）水凝胶与均匀的聚合物网络的聚合物凝胶的线性弹性的实验研究。我们还提供了一个统一的公式为各种网络拓扑结构和密度的聚合物凝胶的线弹性。利用统一公式，我们调和了过去的实验结果似乎彼此不一致。最后，我们提到，仍然有基本的未解决的问题，涉及聚合物凝胶的线性弹性。
We recently found that the energy contribution to the linear elasticity of polymer gels in the as-prepared state can be a significant negative value; the shear modulus is not proportional to the absolute temperature . Our finding challenges the conventional notion that the polymer-gel elasticity is mainly determined by the entropy contribution. Existing molecular models of classical rubber elasticity theories, including the affine, phantom, and junction affine network models, cannot be used to estimate the structural parameters of polymer gels. In this focus review, we summarize the experimental studies on the linear elasticity of polymer gels in the as-prepared state using tetra-arm poly(ethylene glycol) (PEG) hydrogels with a homogenous polymer network. We also provide a unified formula for the linear elasticity of polymer gels with various network topologies and densities. Using the unified formula, we reconcile the past experimental results that seemed to be inconsistent with each other. Finally, we mention that there are still fundamental unresolved problems involving the linear elasticity of polymer gels.