This award supports theoretical research and education on polymeric membranes possessing both enhanced mechanical and electrochemical properties. Recent experiments aiming to develop polymeric membranes with these properties explore a variety of strategies, including cross-linking of the conductive homopolymers, use of inorganic fillers to create polymer nanocomposite membranes, and using diblock copolymers in which a mechanically strong block complements the conducting phase. While mechanical properties can be enhanced by such means, intriguing observations have also been noted in the dependencies of transport properties upon the physicochemical parameters that characterize these modified polymer membranes.
Motivated to understand the transport properties, the PI plans to study the physics of diffusion processes involving ions and large molecule penetrants in two broad classes of systems: (i) Polymer membranes containing nanoparticulate fillers: the PI aims to use a hybrid simulation approach combining atomistic level molecular dynamics with a coarse-grained kinetic Monte Carlo approach to probe the mechanistic origins of the behavior of the conductivity of polymer nanocomposite membranes. The PI will use such a simulation approach to interrogate the filler-induced modifications to the ion motion, complexation and polymer motion, and to unravel the roles of the polymer-filler interactions and particle concentrations; (ii) Nanostructured/self-assembled block copolymer membranes: The PI plans to use a coarse-grained bond fluctuation Monte Carlo simulation approach to probe the mechanistic underpinnings of the behavior of the conductivity and transport properties of block copolymer membranes. In particular, the PI proposes to use simulations within the context of a non-charged, selective solvent representation of the ion to unravel the interplay between ion motion, polymer dynamics, the morphology of self-assembly, and composition fluctuations upon the macroscopic transport properties of the membrane.
This research is expected to result in a better understanding of the mechanisms underlying ion and large molecule penetrant diffusion in such structured and inhomogeneous polymeric matrices. Advances in computational approaches and theoretical models for studying ionic and penetrant transport using atomistic and coarse-grained simulations will be made in the course of this project. Resulting methods may also have applications to fuel cells and water purification membranes.
The educational broader impacts are integrated with research aims, and include opportunities for undergraduate researchers to participate in this project with an aim to include students from community colleges. An international workshop devoted to fundamental aspects of coarse-graining the equilibrium and dynamical aspects of soft-matter systems will also be organized.
Non-Technical Summary
This award supports theoretical research and education that can contribute to developing improved batteries and fuel cells. Electrochemical devices such as batteries and fuel cells have recently become popular in the quest for clean and sustainable energy sources. Many present-day batteries involve the presence of a liquid electrolyte which serves to conduct ions between the positively charged terminal and the negatively charged terminal. However, the presence of this liquid component leads to potential safety issues. To enhance safety, researchers seek to develop conducting media, electrolytes, which are non-flammable but still ensure efficient operation of the batteries. In this context, plastics have emerged as potential candidates. However, it remains a challenge to design plastic materials that are strong enough and have properties that lead to efficient battery operation.
The PI will develop computer-based tools to investigate new classes of polymeric materials which have been demonstrated to possess properties desirable for batteries. The computer-based tools will provide means to interrogate the operation of the polymeric materials and thereby suggest directions for designing new materials with better and improved properties. The tools developed in this project are can be adapted to study other renewable energy options such as fuel cells and the operation of water purification membranes.
This project will create new research opportunities for both undergraduate and graduate students to study the newly emerging classes of materials and thereby suggest strategies for improving their properties. Moreover, new courses and demonstration modules will be designed to educate students and the public on the principles underlying devices such as fuel cells, batteries, and solar cells.
