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

利用发光探针方法揭示物理凝胶的动态形成机制和老化

基本信息

批准号：
13650948
负责人：
ITAGAKI Hideyuki
金额：
$ 2.11万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

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.

1. 为了获得热可逆琼脂糖和明胶水凝胶的微观信息，我们添加了8-苯胺-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浓度、分子量和温度的依赖性。光谱分析表明，有两种类型的3_1螺旋型参与琼脂糖的凝胶化。ANS荧光性质的温度依赖性表明，在凝胶熔融温度下，螺旋形并没有分解成随机线圈形，而是螺旋棒的聚集只是松散地变成一个或几个孤立的螺旋棒。辛二规聚苯乙烯（sPS）是否形成凝胶取决于溶剂。我们的荧光探针技术表明，在溶剂如氯仿、苯和甲苯的情况下，由于聚合物-溶剂化合物的形成，它们在sPS链之间有一定的自由体积。相反，对于溶剂，如反式十氢化萘，由于太大而不能停留在sPS链之间，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 -二邻苄基-d -山梨糖醇（DBS）衍生物在不同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、粘弹性和结构性能的影响。综上所述，DBS分子体积庞大，且高度定向于一维，因此无法轻易形成三维晶体；因此，DBS分子被认为不容易形成晶体，而更容易形成纤维结构，这将促进凝胶网络。