CAREER: Molecular Packing of Pi-Conjugated Polymers through Fused Hydrogen Bond-mediated Self-assembly

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NON-TECHNICAL SUMMARY:Understanding and controlling molecular packing in electrically conducting polymers could lead to the design of high-performance polymers, which is important for applications requiring flexible, light, and economical electronic materials. This CAREER research involves the study of new types of polymers that have fused sites along their molecules enabling hydrogen bonding. Studying the transition from latent to actual hydrogen bonding states will provide the added benefit of direct patterning of conducting polymers, leading potentially to more efficient fabrication of integrated circuits in organic electronics. Results of this research will help to build an understanding of the structural control in organic materials and contribute to the elucidation of structure-property relationships for electrically conductive polymers. The educational and outreach component of this project is to motivate and inspire students about science and technology and encourage their consideration of careers in STEM fields, especially targeting underrepresented groups in the STEM fields, including women and minorities. The basic concepts of this research will be disseminated to broader lay audiences through the partnership with the University of Akron (UA) public relations and the Akron Global Polymer Academy who provide research news to the general public and materials to K-12 teachers nationwide, respectively. The educational efforts will be offered to students at all levels from middle school to graduate school through several programs. The PI will design lectures for local science Olympiad targeting middle school students. Through partnership with local high schools and professional societies, summer internships in the lab will be provided to high school students. The PI will continue engaging in outreach targeting local community colleges. In addition, this award will allow the PI to develop a new special topic lecture for conjugated polymers for the students at U. Akron. TECHNICAL SUMMARY:Control of charge transfer in organic materials essentially requires the control of intermolecular interactions to achieve the desired molecular packing, crystal structure, and alignment/interconnection of the crystalline grains. This CAREER research seeks to study pi-conjugated polymers with fused hydrogen bonding on the polymer main chain. Such an analysis will provide a fundamental framework to control the pi-pi stacking by strong and directional intermolecular hydrogen bonds. Results of this research will help to build an understanding of the structural control in organic materials and contribute to the elucidation of structure-electronic property relationships for conjugated polymers. In this research, a complete list of hydrogen bonded pi-conjugated pigment molecules and oligomers based on graph-set theory will be investigated firstly. Next, their single-crystal structures will be explicitly determined to understand how hydrogen bonding will affect the pi-pi stacking of the molecules. Finally, polymers with latent hydrogen bodning will be synthesized and converted to polymers with fused hydrogen bonding. Their thin-film structure, morphology, and electronic properties will be investigated. The technical objectives of the research include: 1) Establish a knowledge base regarding conjugated pigments and conjugated oligomers with fused hydrogen bonds; 2) Create a basis for the rational design of fused hydrogen bonding in conjugated molecules; 3) Investigate the conjugated polymers with fused hydrogen bonding and quantify and elucidate the role of hydrogen bonding in thin-film structure and electronic properties.