NSF Award
2408881
NON-TECHNICAL SUMMARY:<br/><br/>Polymers (plastics) that can conduct both electronic and ionic charge promise to serve as central building blocks for applications ranging from environmental and electrophysiological sensors to energy storage. Key advantages of such mixed conduction polymers include their flexible form factor, their ability to be processed at low temperatures using additive printing approaches such as inkjet or screen printing, and their multifunctional technological capabilities. Through judicious choice of molecular structures, it is also possible to access water-soluble polymers that will enable development of environmentally benign options for a range of sensing, advanced computing, and energy applications. This project aims toward the discovery of new, sustainable mixed conduction polymer chemistries and processes and identify critical structure-function relationships. It will do so through a combination of chemical design and synthesis, molecular and structural characterization, property determination and optimization, as well as through an integrated theoretical and experimental approach. As a result, new generations of mixed conduction polymers having unprecedented performance may be identified. Students engaged in the proposed project will benefit from the multidisciplinary nature of the program, developing technical expertise in balance with the ability to communicate and collaborate with scientists and engineers in other fields. The co-PIs are committed to mentorship of diverse groups of graduate and undergraduate researchers and participation in K-12 student outreach programs to accelerate interest in STEM in underrepresented groups. <br/><br/><br/>TECHNICAL SUMMARY:<br/><br/>Conjugated polymer semiconductors that undergo electrochemically induced doping through permeation of ions from an electrolyte promise to serve as central building blocks for applications ranging from environmental and electrophysiological sensors to light-emitting electrochemical cells, neuromorphic modules, and energy storage. Known as organic mixed ionic-electronic conductors (OMIECs), this class of polymers has characteristics believed to originate from ionically charged or polar side chains that readily solvate or interact with ionic species. To date, the choice of OMIEC chemistries is severely limited whereby transformational advancements in ab initio design require much improved fundamental insight into advantageous synthetically accessible molecular structures and thin-film morphologies that could allow for unprecedented levels of ionic-electronic coupling, compatibility with electrochemical doping, and ion percolation effects. To address limitations in materials design and transport phenomena in OMIECs, this project encompasses the following three Aims: (i) synthesize and characterize target OMIEC structures with unexplored side-chain and backbone paradigms; (ii) establish links between OMIEC backbone and side-chain chemistries and electrolyte gating, film swelling, and ion/electron transport properties through operando studies and molecular modeling; and (iii) explore mixed side-chain chemistries (via copolymerization and/or blending) as a route towards additional control over OMIEC properties. It is hypothesized that expanding the design space available to OMIEC materials via new side-chain chemistries, including additional design capabilities incorporated via copolymerization and blending, could enable unprecedented control over OMIEC properties and device performance. <br/><br/>.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
