Additive manufacturing of functional materials via photopolymer complex synthesis

Abstract

Additive manufg. is one of the most powerful manufg. tools available today, due to its potential in fabricating a wide variety of materials at resolns. ranging from nanometers to meters. In particular, significant advances have been made in polymeric 3D printing, with recent work showing the fabrication of polymers with unique properties, such as self-healing, stimuli-responsive behaviors, and etc. However, there is still a dearth of techniques for the printing of multifunctional metal oxides and metals. Conventional methods involve: a) the patterning of slurries contg. a metal oxide/metal powder, with a subsequent debinding and sintering step, b) printing with inorg.-org. polymers, followed by a similar thermal treatment, or c) the use of a high-powered laser to fuse metal oxide/metal powder together. However, these techniques have difficulties with issues ranging from inhomogeneous dispersion of particles in slurries, challenging synthesis of inorg.-org. resists, to cost of equipment resp. In this presentation, a new technique, called "Photopolymer Complex Synthesis," that addresses some of the challenges above, is demonstrated. Aq. metal-ion contg. photoresins are prepd. and used with photolithog., in conjunction with post-processing techniques to fabricate architected metal oxide or metal structures. These photopolymer systems are facile to prep. and can be modified to fabricate various multifunctional complex metal oxides or alloys. As examples of this technique, we fabricate and characterized zinc oxide (ZnO) and lithium cobalt oxide (LCO) architected structures with sub-micron and sub-millimetre features resp. Compression of the ZnO structures resulted in an electromech. response, and electrochem. cycling of the LCO structures showed efficient performance as a lithium ion battery cathode. We also demonstrate the fabrication and characterization of metal structures made from copper and cupronickel alloys. Our work highlights the use of polymer chem. and materials science in expanding the range of materials that can be made via additive manufg.

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