Horkay Ferenc
Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Gels. 2021 Jul 24;7(3):102. doi: 10.3390/gels7030102.
The objective of this article is to introduce the readers to the field of polyelectrolyte gels. These materials are common in living systems and have great importance in many biomedical and industrial applications. In the first part of this paper, we briefly review some characteristic properties of polymer gels with an emphasis on the unique features of this type of soft material. Unsolved problems and possible future research directions are highlighted. In the second part, we focus on the typical behavior of polyelectrolyte gels. Many biological materials (e.g., tissues) are charged (mainly anionic) polyelectrolyte gels. Examples are shown to illustrate the effect of counter-ions on the osmotic swelling behavior and the kinetics of the swelling of model polyelectrolyte gels. These systems exhibit a volume transition as the concentration of higher valence counter-ions is gradually increased in the equilibrium bath. A hierarchy is established in the interaction strength between the cations and charged polymer molecules according to the chemical group to which the ions belong. The swelling kinetics of sodium polyacrylate hydrogels is investigated in NaCl solutions and in solutions containing both NaCl and CaCl. In the presence of higher valence counter-ions, the swelling/shrinking behavior of these gels is governed by the diffusion of free ions in the swollen network, the ion exchange process and the coexistence of swollen and collapsed states.
本文的目的是向读者介绍聚电解质凝胶领域。这些材料在生物系统中很常见，并且在许多生物医学和工业应用中具有重要意义。在本文的第一部分，我们简要回顾了聚合物凝胶的一些特性，重点是这类软材料的独特特征。突出了未解决的问题和未来可能的研究方向。在第二部分，我们聚焦于聚电解质凝胶的典型行为。许多生物材料（如组织）是带电（主要是阴离子）的聚电解质凝胶。通过示例来说明抗衡离子对模型聚电解质凝胶的渗透溶胀行为和溶胀动力学的影响。随着平衡浴中高价抗衡离子浓度逐渐增加，这些体系会呈现体积转变。根据离子所属的化学基团，阳离子与带电聚合物分子之间的相互作用强度建立了一个层级关系。研究了聚丙烯酸钠水凝胶在氯化钠溶液以及含有氯化钠和氯化钙的溶液中的溶胀动力学。在存在高价抗衡离子的情况下，这些凝胶的溶胀/收缩行为受自由离子在溶胀网络中的扩散、离子交换过程以及溶胀和塌陷状态共存的支配。
