Research Initiation: Volume Change Kinetics in Near-Critical Gels

在一个临界点附近突然的体积变化是聚合物凝胶的一个独特的性质，许多商业产品正在开发。该项目全面研究了凝胶在临界点附近的体积变化动力学。将异丙基丙烯酰胺与二乙基丙烯酰胺或丙烯酸共聚，可制得一系列超临界和亚临界凝胶。体积变化的动力学将通过称重测量质量变化和用视频显微镜系统测量尺寸变化来确定。目标是将广泛的动力学现象联系在一起：连续和不连续的体积变化；膨胀和收缩；pH、溶剂、离子强度和温度变化引起的体积变化；以及凝胶结构变化的影响。这些结果将为面向应用的研究提供所需的数据，阐明这些变化的相对速率，并指导开发适当的数学模型。

Abrupt volume change near a critical point is a unique property of polymer gels on which many commercial products are being developed. This project undertakes a comprehensive study of volume change kinetics in gels near the critical point. A range of supercritical and subcritical gels will be created by copolymerizing isopropylacrylamide with diethylacrylamide or acrylic acid. The kinetics of volume changes will be determined by measuring the change in mass by weighing and the change in dimension with a videomicroscope system. The objectives are to tie the broad range of kinetic phenomena together: continous and discontinous volume changes; swelling and shrinking; volume changes induced by variations in pH, solvent, ionic strength, and temperature; and the effect of changes in gel structure. The results will provide data needed for application-oriented research, clarify the relative rates of these changes, and guide development of an appropriate mathematical model.