Dynamic Formation Mechanism and Aging of Physical Gels Revealed Using Luminescent Probe Method

1.为了获得热可逆琼脂糖和明胶水凝胶的微观信息，我们加入了8-苯胺基-1-萘磺酸（ANS），其荧光行为强烈依赖于其微环境的极性。我们测量了ANS的荧光和荧光各向异性对生物聚合物的浓度和分子量以及温度的依赖性。光谱分析表明，有两种3_1螺旋形式参与琼脂糖凝胶化。ANS荧光性质的温度依赖性表明，在凝胶熔融温度下，螺旋形式不会分解为无规卷曲形式，而是螺旋杆的聚集体只是变得松散，一个或一些孤立的螺旋杆.间规聚苯乙烯（sPS）是否形成凝胶取决于溶剂。我们的荧光探针技术澄清，在溶剂的情况下，如氯仿，苯，甲苯，有一些自由体积为他们留在sPS链之间，因为形成的聚合物-溶剂化合物。相反，在溶剂如反式萘烷的情况下，其太大而不能留在sPS链中，sPS不能形成聚合物-溶剂化合物，因此它永远不会形成凝胶。为了阐明1，3：2，4-二-O-亚苄基-D-山梨醇（DBS）衍生物在各种溶剂中形成和稳定凝胶的主要驱动力，详细研究了衍生物浓度对凝胶的热、粘弹性和结构性质的影响。总之，DBS分子是如此庞大且如此高度取向于一个维度，以至于它不能容易地形成三维晶体;因此，DBS分子被认为不容易形成晶体，而是形成纤维结构，这将促进凝胶网络。

1. In order to get microscopic information of thermoreversible agarose and gelatin hydrogels, we added 8-anilino-1-naphtalene sulfonic acid (ANS) whose fluorescence behavior strongly depends on polarity of its microenvironment. We measured the dependence of both fluorescence and fluorescence anisotropy of ANS on concentration and molecular weight of biopolymers, and temperature. Spectral analysis has clarified that there are two types of 3_1 helix form taking part in gelation of agarose. The temperature dependence of ANS fluorescence properties suggest that at the gel melting temperature the helical form does not break down to random coil form but rather the aggregation of helix rods just becomes untied and one or some isolated helix rods.2. Whether syndiotactic polystyrene (sPS) forms gel or not is dependent on solvent. Our fluorescence probe technique clarified that in the case of solvents such as chloroform, benzene, and toluene there are some free volume for them to stay among sPS chains because of the formation of polymer-solvent compounds. Conversely , in the case of solvents such as trans-decalin that are too large to stay among sPS chains, sPS cannot form polymer-solvent compounds, and consequently it never forms a gel.3. To clarify the primary driving force in the formation and stabilization of gels of the derivatives of 1, 3 : 2, 4-di-O-benzylidene-D-sorbitol (DBS) in various solvents, the effects of derivative concentrations on the thermal, viscoelastic, and structural properties of the gels were examined in detail. In conclusion, a DBS molecule is so bulky and so highly oriented to one dimension that it cannot readily form a three-dimensional crystal ; as such, DBS molecules are assumed to not easily form a crystal but rather to form a fiber structure, which would promote the gel network.