Molecular Modeling of Rigid-Rod Polymers Structures Dominated by Electrostatic Interactions

摘要

This report results from a contract tasking Institute of Macromolecular Compounds of Russian Academy of Science as follows: PBO, a rigid rod polymer developed by the Air Force Materials Laboratory and now commercially available from Toyobo, has considerable promise for applications as separator membranes in advanced fuel cells and batteries. In such applications, the performance of the membrane is intimately related to the structure of the polymer. In PBO as well as any other polymer used to provide a pathway for ionic conduction, electrostatic interactions are likely to play a dominant role in defining that structure. PBO is a lyotropic liquid crystalline polymer which is soluble only in very strong acids, from which it is processed into fibers or films. Electrostatic interactions may play a very large role in their structure formation by virtue of the charged groups on the polymer itself and the small counter-ions which accompany them. Understanding these interactions may ultimately provide a means of tailoring the morphology which the polymer adopts. We propose to undertake a molecular modeling study of the effect of strong acids on the structure and properties of PBO in solution and bulk state by applying the molecular mechanics approach. Such studies are necessary before larger scale molecular simulations addressing the physical processes underlying of the development in the processing membranes and fibres of the fibrillar structure can be undertaken.