A Critical Test of Reptation Dynamics

这个SGER处理的是聚合物科学中的一个基本问题，即大分子是如何相互移动的？德·热纳等人支持的一个广泛观点是，大分子以蛇形的方式移动，即通过复制。重复似乎在某些情况下成立，但在其他情况下则不然。在缺乏决定性实验的情况下，这一理论因此变得有争议。这项研究旨在提供一个具有欺骗性的测试。它将包括精心制备一系列在链的两端或中心有氘化的聚合物。然后，利用中子反射率和其他方法，在各种条件下研究分子的扩散。这种仔细的聚合物动力学测试是必要的。如果成功，这些实验要么是对该理论的决定性检验，要么至少为解决这一问题的其他实验指明了道路。在这两种情况下，聚合物的流变学都将建立在更科学的基础上。

This SGER deals with a fundamental problem in polymer science, namely how do giant molecules move with respect to each other? A widely held view, espoused by de Gennes and others, is that macromolecules move in a snakelike fashion, i.e., by reptation. Reptation seems to hold under some conditions, but not under others. In the absence of decisive experiments, the theory has, therefore, become controversial. This research aims to provide a decive test. It will consist of careful preparation of a series of polymers with deuteration either at the ends or in the center of the chains. The diffusion of the molecules will then be studied under a variety of conditions, using neutron reflectivity and other means. This careful test of polymer dynamics is needed. If successful, the experiments will either be a decisive test of the theory or at least point the way to other experiments that should settle this issue. In either case, rheology of polymers will be put on a more scientific basis.