Date: Tuesday, May 23, 2023
Time: 11:30 am - 1:00 pm EST

Plenary Lecture

Prof. Dr. Martin U. Schmidt, Goethe University

Title: Crystal Engineering on industrial organic pigments

Abstract: Organic pigments are industrially used for the coloration of printing inks, plastics, lacquers and coatings, with a worldwide sales volume of about 6 billion USD. There are two main chemical classes (1) hydrazone pigments (formerly called "azo pigments") synthesized by diazotation and azo coupling of aromatic precursors, (2) heterocyclic pigments built from annulated aromatic and heterocyclic rings. Pigments are fine powders with crystallite sizes between 50 and 500 nm. They are insoluble in the application media (e.g. plastics or printing ink), they are just finely dispersed. Correspondingly, the crystal structures are maintained, and the optical, mechanical and thermal properties of the final product depend on the crystal structures of the pigments. Most pigments exist in different polymorphs with different colors. Crystal structure determination is challenging, since generally no single crystals can be grown. Correspondingly, we determined most of the crystal structures by X-ray powder diffraction. With the knowledge of the crystal structures, crystal engineering can be applied, i.e., a synthesis of new pigments with desired optical properties and improved stabilities. Examples include the improvement of the color of quinacridone pigments, the photo stability of an hydrazone pigment, the density of a dioxazine pigment and the extinction coefficient (i.e. the color strength and, hence, the achievable sales price) of the yellow hydrazone pigments used for newspaper printing.

Time: 11:30 am

Short Talks

Peiyuan (Tony) Qu, Harvard University
Postdoctoral Research Fellow - Aizenberg Group

Title: Encoding Morphogenesis of Untethered Liquid Crystalline Elastomers (LCEs) Microactuators with Droplet Microfluidics and Mechanics

Abstract: As miniaturization of robots becomes important (e.g. in biomedical applications), creating biomimetic actuators at the microscopic scale with precise geometry, functional patterns, and programmable microactuation is highly desired, but challenging. Inspired by Nature’s ability of morphogenesis, we describe a soft manufacturing to orthogonally fabricate untethered liquid crystal elastomer (LCE) microactuators with various shape, surface pattens, and predetermined microactuation and their applications towards bioinspired soft microrobotics. Hydrogel microfibers containing arrays of prepolymer microparticles were fabricated via droplet microfluidics. Simple mechanics, such as gravity, buckling, were used in a discrete or a synergic way to create 3D shape (e.g. spheres, spindles, rods, chains) as well as surface pattern. After polymerization in the magnetic field to program the mesogenic orientation, the resulting LCE microactuators displayed distinct deformations upon heating, which were validated with finite element analysis. We foresee these microactuators have great potentials in bioinspired microrobots, energy harvesting, and dynamic functional architectures.

Time: 12:10 pm EST

Madeleine Gaidimas, Northwestern University
Ph.D. Candidate - Farha Group

Title: Separation of Thorium from Rare Earth Elements Through Selective Crystallization

Abstract: Rare earth elements are crucial resources for myriad technologies including magnets, batteries, and alloys. Yet despite their importance, pure rare earths are difficult to obtain due to the complexity of their ores, which contain numerous transition metals as well as radioactive thorium. Current separation methods are inefficient and involve extensive solvent usage and waste production. Here, I will describe an alternative strategy to separate impurities from rare earth elements using a selective crystallization approach inspired by the nuances of metal–organic framework formation. By leveraging the metal-dependent kinetics of crystallization, thorium can be efficiently separated from rare earth ions in solution. With this heterogeneous approach, crystalline products can be easily removed, reducing the waste and solvent demands of current rare earth processing approaches.

Time: 12:35 pm