Basic Study on Molecular Motion in Suplamolecules and Its Application by Field Gradient NMR and ESR.

凝胶/阳离子/水体系的I螺旋转变和溶胶-凝胶转变用核磁共振弛豫时间和摩尔椭圆度研究了这两个转变的阳离子依赖性。螺旋转变的转变温度和可逆性表现为阳离子依赖性，其中KandCs离子对凝胶转变的影响不同于其他碱性阳离子。对于Sol-Gel转变，二价阳离子通过形成交联剂来促进凝胶的形成，而一价阳离子首先屏蔽了凝胶链上的阴离子电荷，然后通过氢键促进了凝胶的凝胶。根据水的氢键行为解释了凝胶化机理。II葡聚糖/阳离子/水体系的凝胶化机理K-核磁共振和水的扩散性证明，只有K离子参与了中性葡聚糖聚合物的钾键凝胶化。K离子的选择性是由于K离子的离子半径和水化行为：…较多的钠离子增强了K/葡聚糖凝胶的结构，导致凝胶的热稳定性。III低粘度和高粘度凝胶的凝胶形成机理柯德兰凝胶的形成过程显示出非常复杂的链结构变化。水的流动性和质子交换在细节上反映了这种变化。凝胶基质中存在三种类型的水。IV普鲁兰多糖溶液中的水化行为高浓度的普鲁兰多糖溶液在聚合物链周围形成一个稳定的水化球体，水合水分子在那里运动交换到本体水中的速度非常缓慢。研究了普鲁兰凝胶在普鲁兰溶液中的特殊水化行为。V淀粉和柯德兰凝胶的冻结和解冻过程用自旋探针ESR方法进行监测，检测到无定形冻结的水分子，并估算了水的量。对过冷、未冻结和冻结水分子的转动关联时间进行了估算。较少

I Coil-Helix Transition and Sol-Gel Transition in Gellan / Cation / Water SystemCation dependence of both transitions has been studied by NMR relaxation time and molar ellipticity by CD.The transition temperature and a reversibility in the coil-helix transition showed cation dependence, in which KandCs ions differently affected from other alkali cations, For the sol-gel transition, divalent cation enhanced the gelation by forming crosslinks, while monovalent cation firstly contributed a shielding of anionic charge of gellan chain and then helped the gelation by hydrogen-bonding. Gelation mechanism was explained on the basis of the hydrogen bonding behavior of water which clearly appears in T_2 relaxation time.II Gelation Mechanism in Dextran / Cation / Water SystemOnly K ion contributed to gelation of the neutral dextran polymer by potassium bonding, which was proved by K-NMR and water diffusibility. The selectivity for K ion is due to the ionic radius and hydration behavior of K ion : … More Na ion enhanced K/dextran gel structure and resulted thermal stability of the gel.III Gel Formation Mechanism for Low-set and High-set Curdlan GelsGel formation process of the curdlan showed very complicated structural change of the chain. Water mobility and proton exchange reflected the change in details. Existence of three types of water in the gel matrix was proved by spin-probe ESR method in cooling and heating process.IV Hydration Behavior in Pullulan SolutionHigh concentration of pullulan solution showed a stable hydration sphere around the polymer chain, where motional exchange of hydrated water molecules into bulk water was very slow. The specific hydration behavior in pullulan solution was investigated.V Freezing and Thowing Process in Starch and Curdlan GelsThe process was monitored by spin-probe ESR method An amorphously freezing water molecules were detected and the amount of the water was estimated. Rotational correlation time was evaluated in super-cooled, unfrozen and frozen water molecules. Less