September 20, 2019 @ 11:00 am - 12:00 pm
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Mechanics-Driven Extreme Transfer Printing of Functional Films
Department of Mechanical and Aerospace Engineering, University of Virginia
Transfer printing is a technology of assembling layered structures down to the nanoscale by picking up a thin film processed on a native substrate prior (e.g. as-fabricated wafers, and as-growth metals) and releasing it onto a target substrate and is the foundation in the manufacturing of an entire class of wearable technologies, in particular, film-based electronics and devices. In this talk, I will first present a novel strategy of transfer printing that enables the delivery and assembly of deterministic functional film structures in a liquid environment, defined as the hydrolysis transfer printing by us. Unlike that in dry air, the presence of liquid molecules will promote the interfacial debonding by substantially decreasing interface strength and is fundamentally underpinned by a synergistic effect of both external mechanical loading and interior hydrolysis at interfaces. The establishment of hydrolysis-based chemomechanics theory and its implementation into the finite element model for a multiscale-multiphysics computational framework will be discussed. The guided applications in the transfer printing of a broad variety of materials, including two-dimensional materials, silicon nanomembrane, and three-dimensional plasmonic nanoarchitectures will be demonstrated. After that, I will talk a transfer printing approach of films from the surface of a liquid, defined as the capillary transfer printing by us. This capillary transfer is underpinned by the physical transfer front of contact among substrate, liquid and film and can be well controlled by a selectable moving direction of receiver substrates–push-down or pull-up. Extensive experiments, together with comprehensive theoretical models and computational simulations, on a broad material diversity of film, liquid, and substrates will be given to demonstrate the robust capabilities of this capillary transfer printing.
Dr. Baoxing Xu is currently an assistant Professor in the Department of Mechanical and Aerospace Engineering at The University of Virginia (UVA). He received his PhD in Mechanics and Materials from Columbia University in 2012 and was a Beckman Postdoctoral Fellow at the University of Illinois at Urbana-Champaign from 2012 to 2014. Dr. Xu’ s group research interests are focused on mechanics-driven extreme design and manufacturing of functional materials, structures and devices, in particular, low-dimensional nanomaterials, porous structures, bioinspired stretchable devices and structures, soft-hard material integrated systems. He has published over 30 peer-reviewed research articles in the leading journals at UVA, including PNAS, Journal of the Mechanics and Physics of Solids, Advanced Materials, Nano Letters, and ACS Nano. He served the guest editor of the themed issue “Mechanics in Extreme Manufacturing” for the journal Extreme Mechanics Letters.