Location:
Hudson Beare Building, Lecture Theatre 2, King's Buildings
Date:
Low electrical conductivity (s) and thermopower (S) have long excluded polymers from thermoelectric applications. Combining polyaniline (PANi) with double-walled carbon nanotubes (DWNT) and graphene produces polymer nanocomposites that exhibit excellent thermoelectric behavior (i.e., generate electricity via a thermal gradient). Electrical conductivity greater than 100,000 S/m, with a Seebeck coefficient of 130 mV/K, yields completely organic materials produces a power factor (PF = S2s) greater than 3000 mW/(m•K2), making these nanocomposites competitive with inorganic semiconductors (e.g., bismuth telluride) in terms of conversion efficiency. These water-based systems can be applied like ink or paint, so they can harvest waste heat from a variety of sources (e.g., exhaust manifolds or the human body). In another aspect of our work, we have imparted flame retardant behaviour to woven fabrics using an environmentally-benign coating method. Aqueous complexes, containing polyethylenimine (PEI) and ammonium polyphosphate (APP) forms melamine polyphosphate in-situ during exposure to a melamine-containing solution. Nylon-cotton blended fabric was rendered self-extinguishing with less than 20 wt% coating. The effectiveness of this halogen-free, flame retardant coating is due to condensed phase activity that includes cooling effects and charring. The ease of this coating procedure and the use of more environmentally benign chemicals deposited from aqueous solutions make this an industrially feasible alternative to current treatments for cotton and cotton-based blends. Our work in these areas has been highlighted in C&EN, ScienceNews, Nature, Smithsonian Magazine, Chemistry World and various scientific news outlets worldwide.
Biography
Jaime Grunlan is the Linda & Ralph Schmidt '68 Professor of Mechanical Engineering. He obtained a B.S. in Chemistry from North Dakota State University and a Ph.D. in Materials Science and Engineering from the University of Minnesota. Prof. Grunlan was promoted to Full Professor in 2014, becoming the Linda & Ralph Schmidt '68 Professor in 2015. His research focuses on thermal and transport properties of nanocomposite materials, especially in the areas of thermoelectric energy generation, gas barrier and fire prevention. He won the NSF CAREER and 3M Untenured Faculty awards in 2007, the Dow 2009 Young Faculty Award, the 2010 Carl A. Dahlquist Award, the 2012 L.E. Scriven Young Investigator Award, sponsored by the ISCST, the 2013 E. D. Brockett Professorship, the 2014 Texas A&M Engineering Experiment Station Fellowship and 2015 Dean of Engineering Excellence Award for his work in these areas. He has published over 120 journal papers and filed several patents. He has graduated 17 PhD students. Dr. Grunlan also holds joint appointments in Chemistry and Materials Science and Engineering. He is an Editor for Journal of Materials Science, Associate Editor for Green Materials and serves on the International Advisory Board for Macromolecular Rapid Communications and Macromolecular Materials and Engineering.
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