Yining Chen
(Advisor: Prof. George A. Kardomateas]

will defend  a doctoral  thesis entitled,

MOLTEN-BASED 3-D DIRECTWRITE FABRICATION OF MICRO STRUCTURES

On

[date & time] Friday, October 29 at 9:00 a.m.
[building & room] Montgomery Knight Building 325
[and Bluejeans https://bluejeans.com/893725406/6170]

Abstract
The micro fabrication is more and more important in science and engineering field. The planar microfabrication technology has difficulties in making 3D or very high aspect ratio structures due to it is mainly a 2D process. Meanwhile, the demand for 3D micro-structures or high aspect ratio microstructures is increasing in various fields, such as micro needle array, micro antenna etc. The mechanical strength and surface roughness of the ink-based 3D micro fabricated structures are far from satisfying. We develop a direct-write method to fabricate 3D/high aspect ratio microstructures to solve this problem. Our method is based on molten glass extruding from a nozzle by pressure to form microstructures on the substrates. These critical dimensions of the structures can be as small as hundred nanometer while maintaining hundreds of aspect ratio. We explore the mechanism in the fabrication and realize precise control of the process. The bonding and mechanical strength of the fabricated structures are also strong enough to serve as senor or mold for sequential processes. High aspect ratio or complex microstructures are made by this method. The process can be stacked up together to fabricate more complex or more dense structures. Very high dense and aspect ratio structure arrays are readily fabricated. For the fabricated microneedle arrays by this technique, molding is used to get polymer replica which has many applications in biomedical field, such as medical drug/vaccine delivery, bio-signal monitoring, etc.

              The method described in this research is believed to be unique in the field of 3-D fabrication, and provides an efficient tool for fabricating micro/sub-micro structures with strong mechanical property, ultra-smooth surface, high aspect-ratio and spatial density that are either unfeasible or extremely costly by other traditional fabrication methods. Moreover, combine with other process such as molding, replica of these microstructures could be made and further extended application to new field. Fabricating more complicated 3-D structures beyond the glass material system based on the mechanisms and processes described in this research would also be feasible in an efficient way.

Committee

• Prof. George A. Kardomateas – School of Aerospace Engineering (advisor)
• Prof. Claudio Vinicius Di Leo – School of Aerospace Engineering
• Prof. Julian Rimoli– School of Aerospace Engineering
• Prof. Ting Zhu – School of Mechanical Engineering
• Prof. Sathyanaraya Hanagud– School of Aerospace Engineering