Studies on Reaction Kinetics and Structure of Polymer Gels by Photon Correlation Spectroscopy

冻结（静态）不均匀性以及热（动态）浓度波动存在于凝胶中。我们提出了一个相关的方法来表征和分解这两个贡献，即，冻结的不均匀性和热波动。该方法包括在数百个样品位置的动态光散射测量。这被称为整体平均动态光散射（EADLS）。这项工作的另一个亮点是确定凝胶化阈值的四种方法。在经历交联的化学反应期间，在凝胶化阈值处出现四个特征性特征：（i）散射强度的突然增加，（ii）时间-强度相关函数（ICF）中的幂律行为，（iii）衰减时间分布函数的特征性加宽，以及（iv）ICF的初始振幅从1的偏差。这些方法的有效性进行了检查有机化学凝胶，无机硅胶，和热可逆的物理凝胶。我相信，这些工作承诺在软物质物理学丰富的领域，作为科学的连通性相关的聚合物材料。

Frozen (static) inhomogeneities as well as thermal (dynamic) concentration fluctuations are present in gels. We proposed a relevant method to characterize and decompose the two contributions, i.e., the frozen inhomogeneities and thermal fluctuations. This method consists of dynamic light scattering measurements at hundreds of sample positions. This is called the ensemble-average dynamic light scattering (EADLS). Another highlight of this work is the four methods of determining a gelation threshold. During a chemical reaction undergoing cross-linking, four characteristic features appear at the gelation threshold; (i) an abrupt increase in the scattered intensity, (ii) a power-law behavior in the time-intensity correlation function (ICF), (iii) a characteristic broadening of the decay time distribution function, and (iv) a deviation of the initial amplitude of ICF from unity. The validity of these methods was examined for organic chemical gels, inorganic silica gels, and thermoreversible physical gels. I believe that these works promise a rich field in soft matter physics, as the science of connectivity-correlated polymeric materials.