The Group welcomes Dr. Xuejin Yang as a new postdoctoral researcher!
The Materials Science and Engineering Department has appointed AJ as an affiliate faculty member. We’re looking forward to exciting interdisciplinary work and interdepartmental activities.
Production of objects with varied mechanical properties is challenging for current manufacturing methods. Additive manufacturing could make these multimaterial objects possible, but methods able to achieve multimaterial control along all three axes of printing are limited. Here we report a multi-wavelength method of vat photopolymerization that provides chemoselective wavelength-control over material composition utilizing multimaterial actinic spatial control (MASC) during additive manufacturing. The multicomponent photoresins include acrylate- and epoxide-based monomers with corresponding radical and cationic initiators. Under long wavelength (visible) irradiation, preferential curing of acrylate components is observed. Under short wavelength (UV) irradiation, a combination of acrylate and epoxide components are incorporated. This enables production of multimaterial parts containing stiff epoxide networks contrasted against soft hydrogels and organogels. Variation in MASC formulation drastically changes the mechanical properties of printed samples. Samples printed using different MASC formulations have spatially-controlled chemical heterogeneity, mechanical anisotropy, and spatially-controlled swelling that facilitates 4D printing.
This paper is our initial demonstration of multimaterial vat photopolymerization using “a chemist’s bottom-up approach.” We look forward to expanding the materials scope, chemical space, and collaborative efforts on this program. Here is a link …
The Chemical and Biological Engineering Department has appointed AJ as an affiliate faculty member. We’re looking forward to exciting interdisciplinary work and interdepartmental activities.
Congrats to Daniel Lee and Tori Kensy! Their work, in collaboration with Prof. Brian Long and Christopher Maroon (each at UT-Knoxville), was just accepted for publication in Angewandte Chemie. This paper describes the mechanochemical conversion …
Herein we report the discovery of the intrinsic mechanochemical reactivity of vinyl-addition polynorbornene (VA-PNB), which has strained bicyclic ring repeat units along the polymer backbone. VA-PNBs with three different side chains were found to undergo ring-opening olefination upon sonication in dilute solutions. The sonicated polymers exhibited spectroscopic signatures consistent with conversion of the bicyclic norbornane repeat units to the ring-open isomer typical of polynorbornene made by ring-opening metathesis polymerization (ROMP-PNB). Thermal analysis and evaluation of chain scission kinetics suggest that sonication of VA-PNB results in chain segments containing a statistical mixture of vinyl-added and ROMP-type repeat units.