Seminar
Traditional methods of scientific inquiry and engineering design begin with human intelligence: Mathematical models encoding physical hypotheses are proposed, tested against experimental data and refined by fitting adjustable parameters.
Jiajie Huo, Postdoctoral Associate – Medlin Lab Tuesday, Nov. 30, 2021 2:45 p.m., JSCBB A108 "Catalyst Development for Aqueous-phase Biomass Conversion and Gas-phase Methane Activation" Seminar Abstract Catalysis plays a crucial role in the
The conversion of intermittent solar radiation into storable and transportable chemical fuels can enable access to sustainable feedstocks and dispatchable sources of power, regardless of geographic location. Of particular interest is technologies that facilitate the endothermic dissociation of water and carbon dioxide while utilizing heat that is obtained via concentrating optics and/or renewable sources of electricity.
Liquid crystalline materials (LCMs) showcase extensive potential for application in a range of industries including soft robotics, optics, and, more recently, biomaterials. By patterning the mesogen alignment within these materials, a directed response can be achieved resulting in muscle-like contraction or 3-D deformation. Employing alignment techniques such as surface enforced alignment, photopatterning, and 3-D printing, we seek to further develop these methods to target biologically relevant LCM applications. Here, I will discuss two LCM systems that highlight recent progress in liquid crystalline biomaterials as enzymatic biosensors and substrates for tissue engineering. In the development of the biosensors, we explore the implications of harnessing an enzyme (jack bean urease) within a heavily crosslinked liquid crystalline network (LCN). The network leverages a hydrogen-bonded liquid crystalline mesogen as a chemoresponsive unit, sensitizing the material to ammonia. As the urease enzyme catalyzes the transformation of urea into ammonia, the pre-programmed alignment of the network mesogens is disrupted, resulting in a bulk shape change. In a separate study, surface aligned liquid crystalline elastomers are synthesized to target aligned cell culture for anisotropic tissues such as muscle. Results show a preference for cell growth along the nematic director of LCEs.
Geometric frustration, the incompatibility of local ordering with global geometric constraints, is known to cause anomalous structures, crystal defects, and self-limitation.
Polysaccharides represents an abundant class of biopolymers, of which cellulose in trees and chitin from Crustacea are common examples. Alginates from seaweed have high affinity to divalent cations and form hydrogels by ionic crosslinking.
Mobile robots combine sensory information with mechanical actuation to move autonomously through complex environments and perform specific tasks (e.g., a robot vacuum cleaner). The miniaturization of such robots to the size of living cells (ca. 2-40 mm) is actively pursued for applications in biomedicine, materials science, and environmental sustainability. In pursuit of these “microrobots”, we seek to understand the many mechanisms underlying the self-propulsion of colloidal particles through viscous fluids. Building on this understanding, we seek to design active particles capable of autonomous behaviors such as navigation of structured environments. In this talk, I discuss two recent efforts – on Quincke oscillators and magnetic topotaxis, respectively – that highlight these complementary aims to understand and design active colloids. In part one, I explain how static electric fields drive the oscillatory motion of micron-scale particles commensurate with the thickness of a field-induced boundary layer in nonpolar electrolytes. In part two, I describe how spatially uniform, time-periodic magnetic fields can be designed to power and direct the migration of ferromagnetic spheres up local gradients in surface topography.
Deep learning has begun a renaissance in chemistry and materials. We can devise and fit models to predict molecular properties in a few hours and deploy them in a web browser. We can create novel generative models that were previously PhD theses in an afternoon.
Seminar: Polymer Informatics and High-Throughput Experimentation to Help Us Discover New Sustainable Polymers Speaker: Bradley Olsen, Alexander and I. Michael Kasser Professor of Chemical Engineering, Massachusetts Institute of Technology Host: Dan
Seminar: Active Droplets that Swim, Chase and Organize Speaker: Lauren Zarzar, Assistant Professor, Pennsylvania State University Host: Ryan Hayward Tuesday, September 21, 2021 - 2:45 p.m. - JSCBB A108 Assistant Professor