10.24.25 Dr. Jaime C. Grunlan – Texas A&M University
Protective Nanocoatings from Polyelectrolytes: Flame Retardancy, Gas Barrier, and High Voltage Insulation
Date: October 24, 2025; Time: 2:30 PM Location: PWEB 175
Abstract: Layer-by-layer (LbL) assembly is a conformal coating technology capable of imparting a multiplicity of functionalities on nearly any type of surface in a relatively environmentally friendly way. At its core, LbL is a solution deposition technique in which layers of cationic and anionic materials (e.g. nanoparticles, polymers and even biological molecules) are built up via electrostatic attractions in an alternating fashion, while controlling process variables such as pH, coating time, and concentration. Here we are producing nanocomposite multilayers (50 – 1000 nm thick), having 10 – 96 wt% clay, that can be completely transparent, stop gas permeation, and impart extreme heat shielding to carbon fiber reinforced polymer composites. Similar multilayer coatings exhibit very high dielectric breakdown strength and good thermal conductivity, for protection of high voltage electronics. In an effort to impart flame retardant behavior to fabric using fewer processing steps, a water-soluble polyelectrolyte complex (PEC) was developed. This nanocoating is comprised of polyethylenimine and poly(sodium phosphate) and imparts self-extinguishing behavior to cotton fabric in just a single coating step. Adding a melamine solution to the coating procedure as a second step renders nylon-cotton blends self-extinguishing. A PEC of PEI and polyacrylic acid is able to achieve an oxygen transmission rate below 0.005 cm3/m2/day at 100%RH and a thickness of just 2 m. This is an all-polymer foil replacement technology. Examples of bio-based polyelectrolytes (e.g., chitosan and phytic acid), being used for these same applications, will be shown. These coating techniques can be deposited using roll-to-roll processing (e.g., flexographic printing, dip-coating, or spray-coating). Opportunities and challenges will be discussed. Our work in these areas has been highlighted in C&EN, ScienceNews, Nature, Smithsonian Magazine, Chemistry World and various scientific news outlets worldwide. For more information, please visit my website: https://grunlan-nanocomposites.com/
Biographical Sketch: Dr. Jaime Grunlan is the Leland T. Jordan ’29 Chair of Mechanical Engineering at Texas A&M University, where he has worked for more than 20 years. He holds joint appointments in the Department of Materials Science and Engineering and the Department of Chemistry. He is a world leader in organic thermoelectric materials, super gas barrier layers, and environmentally-benign, flame retardant nanocoatings. He holds 17 issued U.S. patents and several EU patents. He has published more than 230 journal papers, with more than 29,000 citations. His work has been highlighted in Smithsonian Magazine, Nature, and the New York Times. He is an Editor of the Journal of Materials Science and Progress in Organic Coatings, and Associate Editor of Green Materials. In 2018, Prof. Grunlan became a Fellow of the American Society of Mechanical Engineers (FASME) and was awarded a doctorate honoris causa (i.e. honorary doctorate) from the University of South Brittany (Lorient, France). In 2023, he became a Fellow of the American Chemical Society (FACS). In 2024, he became Fellow of the Polymer Chemistry (POLY) and Polymeric Materials: Science and Engineering (PMSE) Divisions of ACS. He also became a Fellow of the National Academy of Inventors (FNAI) in 2024.
10.31.25 Dr. Ahmed F. Ghoniem – Massachusetts Institute of Technology
Solar Thermochemical Hydrogen Production Using Redox Active Materials
Date: October 31, 2025; Time: 2:30 PM Location: PWEB 175
Abstract: Hydrogen is a valuable widely used chemical and an essential component in renewable fuels. Steam-methane reforming is currently used to produce low-cost “grey” hydrogen, that can be turned “blue” by capturing and storing CO2 at extra cost. “Green” hydrogen can be produced via electrolysis at much higher cost. Efforts are underway to advance photosynthesis. Thermochemical methods, in which high temperature non-stoichiometric reduction of metal oxides is followed by lower temperature oxidation using steam, have the potential to reduce the cost and operate at high-capacity factor. The same technology can also reduce CO2 and produce syngas; an essential feedstock for SAF and efuels. This however requires innovations in redox materials, reactor design and system’s integration. I will introduce the technology and our recent advancements. Ceria is the gold standard because of its stability, but its reduction temperature is high and oxygen carrying capacity is low. Effort to develop alternatives, mostly pervoskites, are underway. Significant reduction-oxidation temperature swing makes it necessary to recover most of the sensible heat. We have designed systems employing multiple reactors that circulate between the two stages to maximize regenerative heat recovery. Generating deep vacuum for reduction, a costly endeavor, can be accomplished by staged oxygen evacuation and novel thermochemical or electrochemical pumping technologies. System level analysis shows that: separation energy should be minimized using, e.g., membrane systems; and waste heat recovery on the exothermic oxidation side should be used to produce electricity to power auxiliary components. To enable continuous operations with optimally sized units, specially designed indirectly heated reactors should operate while communicating with thermal energy storage units. A novel system invented at MIT integrates these ideas and is currently undergoing derisking and validation.
Biographical Sketch: Ahmed F. Ghoniem is the Ronald C. Crane Professor of Mechanical Engineering, Director of the Center for Energy and Propulsion Research and the Reacting Gas Dynamics Laboratory. He received his B.Sc. and M.Sc. degree from Cairo University, and Ph.D. at the University of California, Berkeley. His research covers computational engineering, turbulence and combustion, multiphase flow, clean energy technologies with focus on oxy-combustion for CO2 capture, renewable energy, biofuel and solar fuel production. He supervised more than 120 graduate students and post-doctoral students; published more than 500 articles in leading journals and conferences; and consulted for the aerospace, automotive and energy industry. He is fellow of the ASME, the APS, and the Combustion Institute. He received several awards including the ASME James Harry Potter Award in Thermodynamics, the AIAA Propellant and Combustion Award, the KAUST Investigator Award, the “Committed to Caring Professor” at MIT and the Combustion Institute Bernard Lewis Gold Medal.