超支化高分子特性粘度与扩散的理论研究

We propose to study the intrinsic viscosity and self-diffusion behavior of hyperbranched polymers and bio-macromolecules such as proteins and polysaccharides by a combination of analysis theory and computer simulation, based on a partially permeable sphere model. Firstly, we develop a new theory for self-diffusion behavior of polymers of arbitrary architectures that deepens and broadens our work on the hydrodynamic interactions in the core of hyperbranched polymers. Then we apply our theory to explain a number of crossover and anomalous behaviors in the experimental data on intrinsic viscosity and self-diffusion behavior in the literature. Furthermore, we focus on elucidating the relationship between chain branching structure and their dilute solution properties such as intrinsic viscosity and self-diffusion behavior and apply it to hyperbranched polymers. In addition, derive the drainage and drag functions from first principles and also conduct computer simulation to validate our theory. Overall, these proposed directions will greatly advance our understanding of the dynamic properties of dilute polymer solutions; in particular, the application to hyperbranched polymers which is a timely effort, because this is an area of great current interest to polymer chemistry and biochemistry, where there is a strong need for theoretical interpretation of intrinsic viscosity and diffusivity for structural characterization and fractionation of polymers of different topology.

本项目将针对超支化合成功能高分子和蛋白质、多糖等生物大分子，基于部分穿透球模型，严格推导拓扑结构普适的扩散系数理论,以拓宽人们对超支化高分子内部流体力学相互作用的认识；重点阐释超支化高分子支化度对特性粘度与扩散系数的影响；揭示实验发现的特性粘度与扩散系数的过度行为和反常行为；此外，我们还从第一性原理推导携水和泄水函数，并通过计算机模拟给予验证。这几个方面的研究将有利于我们对高分子稀溶液动力学性质的理解，特别为超支化高分子和生物大分子的结构表征和分级提供有力的理论指导。

特性粘度、扩散系数和折光指数是表征高分子稀溶液性质的重要物理量，同时也是材料学和工程应用领域中表征高分子链结构性质的简易表征量。本项目采用计算机模拟与解析理论相结合的方法，基于部分穿透球模型，系统研究了超支化高分子的特性粘度和扩散系数。首先，我们阐释超支化高分子支化度对特性粘度与扩散系数的影响；特别地，我们还从第一性原理推导携水和泄水函数，并通过计算机模拟给予了验证。进一步地，我们合成了一系列不同聚合度（接枝度）的两亲性超支化高分子（核亲水，外壳疏水）；研究了流体力学半径和粘度半径随分子量的变化关系；阐明了混合溶剂性质对树枝状超支化高分子扩散系数的影响规律。通过计算机模拟，明晰了线形与环形高分子链过孔临界流量随链长的变化关系；揭示了临界流量随孔径的变化规律及其分子机理。此外，我们还推导了含盐共混体系的折光率方程。这几个方面的研究将有利于我们对高分子稀溶液动力学性质的理解。其“创新性与水平”达到了“国际同步”。从而，很好地完成了本项目的任务。已在SCI收录期刊发表研究论文11篇，在国际和国内学术会议做邀请报告5次。