Microelectronics and Microhydrodynamics using Thermo-optically induced Microbubbles

Biswas, Aritra (2017) Microelectronics and Microhydrodynamics using Thermo-optically induced Microbubbles. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Aritra Biswas (12MS057)) 12MS057.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

Optical tweezers have been extensively used as a tool for trapping and manipulation of particles due to its versatility, ease of use and contactless manipulation ability. It has vast research as well as industrial applications. Our interest lies in applications involving "thermo-optical" tweezers; tweezers that use thermally driven flow fields mediated by laserinduced micro-bubbles. This report give insights into two specific projects we performed involving the "thermooptical" tweezers setup. The first project involves controlled lithography of soft-oxometalate materials to create continuous patterns. We first describe an experimental apparatus involving Lock-in Amplifier that is capable of measuring small capacitance values (from a few μF to few pF) with good accuracy. We then use the patterning method to design micro-capacitor patterns. This technique could be further used in the development of controlled printable microelectronic circuits. The second project is motivated by our attempt to model the flow fields around thermo-optically induced micro-bubble(s) that has been experimentally observed by us. The flow in the system is mediated by the Marangoni effect arising due to a non-uniform temperature distribution in the system. We first describe a simpler problem involving colloidal particles having active boundary layers. We employ tensorial spherical harmonics to solve the momentum equation. The flow fields have been mapped and shown by vector field representation. We then describe our problem involving laser-induced micro-bubble(s) in a temperature field and deduce a model to solve for the slip-velocity field in the surrounding medium, with specific focus on a one-bubble system and extend it for a two-bubble system. A brief overview of an ongoing project involving ‘biochip’ microfabrication has also been stated.

Actions (login required)

View Item