Micro Manufacturing Colloquium - 24 March 2022

Join us at 16:45 Central European Time (8:45 am Pacific Standard Time) on March 24, 2022 via Zoom link: https://uci.zoom.us/j/99779583973

Jide Han

Department of Mechanical Engineering

KU Leuven

Jide Han is a PhD researcher in the Department of Mechanical Engineering, KU Leuven. His research topic is about ultrashort pulsed laser processing of zirconia based ceramics, including the fundamentals of ultrashort pulsed laser material interaction and the influence of material inhomogeneity on material removal behavior.

ULTRASHORT PULSED LASER PROCESSING OF ZIRCONIA-ALUMINA NANOCOMPOSITES

Compared to the timescale of the laser pulse in ultrashort laser material processing, the thermal diffusion is relatively a slow process and can often be neglected in many situations. When even a small amount of laser energy is compressed into this ultrashort timescale, the laser intensity can be extremely high that can cause strong field ionization of wide band gap materials which is not possible for long pulsed and CW lasers. Zirconia-alumina nanocomposites are widely used as implant materials, including dental implants and hip-joint implants. The differences of the material properties (mainly the band gap) of zirconia and alumina make the composites microscopically inhomogeneous. This inhomogeneity will have influence on the interaction between ultrashort pulsed laser and the composites, therefore may affect the laser processing performance. The focus of this presentation will be the influence of material inhomogeneity of the zirconia-alumina composites on ultrashort pulsed laser processing performance.

Matthew Michaels

Materials and Manufacturing Technology

University of California, Irvine

Matthew Michaels is a graduate student in BiNoM lab, University of California Irvine. His research focusses on electrokinetic micro- and nano- assembly.

GUIDED HEALING OF DAMAGED MICROELECTRODES VIA ELECTROKINETIC ASSEMBLY OF CONDUCTIVE CARBON NANOTUBE BRIDGES

The subject of healing and repair of damaged microelectrodes has become of particular interest as the use of integrated circuits, energy storage technologies, and sensors within modern devices has increased. As the dimensions of the electrodes shrink together with miniaturization of all the elements in modern electronic devices, there is a greater risk of mechanical-, thermal-, or chemical-induced fracture of the electrodes. In this research, a novel method of electrode healing using electrokinetically assembled carbon nanotube (CNT) bridges is presented.

Utilizing the step-wise CNT deposition process, conductive bridges were assembled across ever-larger electrode gaps, with the width of electrode gaps ranging from 20 microns to well over 170 microns. This work represents a significant milestone since the longest electrically conductive CNT bridge previously reported had a length of 75 microns. To secure the created conductive CNT bridges, they are fixed with a layer of electrodeposited polypyrrole (a conductive polymer). The resistance of the resulting CNT bridges, and its dependence on the size of the electrode gap, is evaluated and explained. Connecting electrodes via conductive CNT bridges can find many applications from nanoelectronics to neuroscience and tissue engineering.

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