Dynamics in Highly Rigid Polymers: Solutions to Membranes*

Creating new materials that are capable of energy production and storage to fulfill the present day’s energy crisis is a challenging task. Advancement of energy technology can benefit greatly from the development of more efficient, higher functioning materials that have optimized properties for energy applications. Dynamics of various elements in this type of system have great influence on the system's physical properties and response when use in device configuration. Here I will present two initiatives towards understanding systems with potential for energy applications. The first study looks the dynamics at a rigid luminescent polymer (dinonyl poly-para-phenylene ethynylene (PPE)) in solution and second in a rigid ionomer (sulfonated polyphenylene(SPP)) membranes. PPEs associate spontaneously into several complex fluids in solution, where their side chains impact the association and the conformation of the backbone. As association takes place the motion of the side chain changes accordingly. It is rather surprising that the side chains remain dynamic though macroscopically the structure is frozen. On the other hand, SPP, which makes highly rigid ionic networks in membrane, are immobile but the water trapped in the membrane remains dynamic and occupy multiple sites, either bound or loosely constrained, and bounce between the two. Effect of water content and temperature on dynamics will be discussed.