Nakajima Tasuku, Hoshino Ken-Ichi, Guo Honglei, Kurokawa Takayuki, Gong Jian Ping
Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan.
Global Station for Soft Matter, Hokkaido University, Sapporo 060-0808, Japan.
Gels. 2021 Apr 1;7(2):39. doi: 10.3390/gels7020039.
The equilibrium swelling degree of a highly swollen charged gel has been thought to be determined by the balance between its elastic pressure and ionic osmotic pressure. However, the full experimental verification of this balance has not previously been conducted. In this study, we verified the balance between the elastic pressure and ionic osmotic pressure of charged gels using purely experimental methods. We used tetra-PEG gels created using the molecular stent method (St-tetra-PEG gels) as the highly swollen charged gels to precisely and separately control their network structure and charge density. The elastic pressure of the gels was measured through the indentation test, whereas the ionic osmotic pressure was determined by electric potential measurement without any strong assumptions or fittings. We confirmed that the two experimentally determined pressures of the St-tetra-PEG gels were well balanced at their swelling equilibrium, suggesting the validity of the aforementioned relationship. Furthermore, from single-strand level analysis, we investigated the structural requirements of the highly swollen charged gels in which the elasticity and ionic osmosis are balanced at their swelling equilibrium.
高度溶胀的带电凝胶的平衡溶胀度被认为取决于其弹性压力和离子渗透压之间的平衡。然而，此前尚未对这种平衡进行全面的实验验证。在本研究中，我们使用纯实验方法验证了带电凝胶的弹性压力和离子渗透压之间的平衡。我们使用通过分子支架法制备的四聚乙二醇凝胶（St-四聚乙二醇凝胶）作为高度溶胀的带电凝胶，以精确且分别地控制其网络结构和电荷密度。通过压痕试验测量凝胶的弹性压力，而离子渗透压则通过电势测量来确定，无需任何强假设或拟合。我们证实，St-四聚乙二醇凝胶的两个实验测定压力在其溶胀平衡时达到了良好的平衡，这表明上述关系的有效性。此外，通过单链水平分析，我们研究了高度溶胀的带电凝胶在溶胀平衡时弹性和离子渗透达到平衡的结构要求。
