(624g) Engineering Ion Transport in Polymer Membranes for Water Purification and Energy Applications

Providing sustainable supplies of purified water and energy is a critical global challenge for the future, and polymer membranes will play a key role in addressing these clear and pressing global needs for water and energy. Polymer membrane-based processes dominate the desalination market because they are more energy efficient than thermal desalination processes, and polymer membranes are crucial components in several rapidly developing power generation and energy storage applications that rely on membranes to control, selectively, rates ion transport. Much remains unknown about the influence of polymer structure on even basic intrinsic transport properties, and these relationships must be developed to design next generation polymer membrane materials. The ability to control ion transport in membranes is key to engineering membranes for water and energy applications. Ion transport selectivity in aqueous hydrated polymer membranes can be increased by making the polymer backbone more rigid and by spreading out hydrophilic functional groups within the polymer. To understand the role of polymer backbone rigidity on transport properties, we prepared chemically similar polymers that have different segmental dynamics. At equivalent water content, polymers with slower segmental dynamics are more diffusion selective than those polymers with more rapid segmental dynamics. To investigate the role of hydrophilic functional group spacing within the polymer, we analyzed model materials using microwave dielectric relaxation spectroscopy. This talk presents an overview of research aimed at further understanding fundamental structure/property relationships that govern small molecule transport in polymeric materials considered for desalination and electric potential field-driven membrane applications that can help address global needs for clean water and energy.