Department of Physical Chemistry and General Physics, Tver State University, Tver, 170100, Russia.
Department of Physical Chemistry and General Physics, Tver State University, Tver, 170100, Russia and Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991, Russia.
Soft Matter. 2017 Aug 2;13(30):5168-5184. doi: 10.1039/c7sm00772h.
We discuss the results of experimental studies of the processes of gelation in aqueous solutions of silver nitrate with l-cysteine and its derivatives. We focus on understanding what determines if these small molecules will self-assemble in water at their extremely low concentration to form a gel. A mechanism of gel formation in a cysteine-silver solution (CSS) is proposed. The analysis of the results indicates that filamentary aggregates of a gel network are formed via interaction of NH and C(O)O groups that belong to neighboring silver mercaptide (SM) aggregates. In turn, formation of sulphur-silver bonds between silver mercaptide molecules is responsible for self-assembling these molecules into SM aggregates which can be considered as supramonomers. Free polar groups located on the surfaces of the aggregates can form hydrogen bonds with water molecules, which explains the unique ability of CSS hydrogels to trap water at low concentrations of low-molecular-weight hydrogelators.
我们讨论了在硝酸银的水溶液中 l-半胱氨酸及其衍生物的胶凝过程的实验研究结果。我们专注于理解是什么决定了这些小分子在极其低的浓度下是否会在水中自组装形成凝胶。提出了一种半胱氨酸-银溶液（CSS）凝胶形成的机制。结果分析表明，凝胶网络的丝状聚集体是通过属于相邻银巯基（SM）聚集体的 NH 和 C(O)O 基团的相互作用形成的。反过来，银硫醇分子之间形成硫-银键负责将这些分子自组装成 SM 聚集体，可以将其视为超单体。位于聚集体表面的游离极性基团可以与水分子形成氢键，这解释了 CSS 水凝胶在低浓度低分子量水凝胶形成剂的情况下捕获水的独特能力。
