报告人：Alamgir Karim 教授

主持人：杨曙光 中心副主任

时间：2024年6月15日（星期六）10:00

地点：复合材料协同创新中心大楼A212学术交流室

报告人简介：Alamgir Karim Dow and Welch Chair Professor, and Director of Materials Engineering Program and Director of Polymer and Soft Matter Center at University of Houston. He obtained his Ph.D. in Physics from Northwestern University and post-doc in Chemical Engineering at University of Minnesota. He was Group Leader of Polymer Blends, Combinatorial Methods and Nanomaterials Group at NIST. He became Goodyear Chair Professor of Polymer Engineering, and Co-Director, Akron Functional Materials Center at University of Akron, and was Associate Dean of Research and Institute Director. His areas of interest and research include polymer thin films, surfaces and interfaces and nanocomposites for energy and sustainability. He is a Fellow of the American Physical Society (APS), Fellow of American Association for the Advancement of Science (AAAS), and Fellow of Neutron Scattering Society of America (NSSA).

报告摘要：The talk will cover research summaries in three areas under investigation in our group. 1) Stabilized and E-Field Driven Polymer Coacervates: Many of the unique properties of biological materials are derived from the highly charged nature of the constituent molecules and their diffuse counterion clouds, which often render such materials intrinsically polarizable, and thus highly responsive to electric fields. We investigate a synthetic material of this kind created through the formation of polyelectrolyte coacervates transferred to distilled water to extract excess counterions to form highly stable droplet suspensions in which individual droplets, and their large configurations, can be precisely manipulated with field strengths comparable in magnitude to a 9-volt battery. These materials should be useful in encapsulating, transporting, and delivering various cargos in numerous applications in manufacturing and medicine and as a model system for understanding electrodynamic aspects of living systems. 2) Energy Storage in Ultrathin and 2D Nanofiller Polymer Film Systems: Ultrathin polymer films present unique opportunities to understand the physics and properties of polymers at the nanoscale when the film thicknesses become comparable to the polymer dimensions. We demonstrate that ultrathin glassy polymer (PMMA) films (~100 nm) that exhibit an order of magnitude higher dielectric strength (EBD) and capacitive energy density (Umax ∝ EBD2) of ~27 J/cm3 as compared to the bulk polymer films when used as dielectric capacitors. Further, polymer thin film heterostructure based capacitor of poly(vinylidene fluoride)/poly(methyl methacrylate) with stratified 2D nanofillers (Mica or h-BN nanosheets) (PVDF/PMMA-2D fillers/PVDF) shows an ultrahigh energy density of ≈75 J/cm3 with efficiency over 79%. 3) 2D GO-MXene Membranes for Dye and Salt Separations: Membrane-based water purification is poised to play an important role in tackling the potable water crisis for safe and clean water access for the general population. Several studies have focused on near two-dimensional membranes for this purpose, which is based on an ion rejection technique. However, membrane swelling in these materials has emerged as a significant challenge because it leads to the loss of function. Herein, we report a self-cross-linked MXene-intercalated graphene oxide (GO) membrane that retains ion and dye rejection properties because the physical cross-linking interaction between Ti–O–Ti and neighboring nanosheets effectively suppresses the swelling of the membrane.