Fabrication And Characteristics Of Micro-Bubble Generator Based On Carbon Nanocoils

Carbon nanocoils (CNCs) can be widely used as electro-thermal inductors, electromagnetic inductors, micro-mechanical springs, resonators, electromagnetic wave-absorbers and electromagnetic convertor for its peculiar 3 dimension structure and superior characteristics. In this thesis, we studied a new kind of high efficient bubble generator based on CNCs as heating elements. This microbubble generator has advantages of extreme low power consumption, easy to fabricate and high integration, which can be applied in the area of thermal jet printing technology, micro-fluid visualization and micro-actuator.Firstly, we analyzed electro-thermal property of the microbubble generator using finite element analysis software ANSYS. The minimum input voltage, input power and time for the bubble generator to generate microbubble were calculated by steady-state simulation and time-transient simulation, which provided a theoretic reference for its bubble generation experiment. Secondly, we investigated the MEMS process to fabricate the CNCs based bubble generator, which mainly included the fabrication of the micro electrodes using lithography, sputtering, lift-off techniques, the alignment of CNCs between the electrodes using DEP technology, the contact fixing of dioxide between CNCs and electrodes, as well as the annealing in vacuum and by current to improve the bubble generator. Thirdly, we studied the electrical properties of the bubble generator in air, including the DC property, AC property and temperature-resistance relationship. Finally, we did the microbubble generation experiment and calibrated the relationships between microbubble growth, device resistance, voltage and power consumption. Through comparison with the characteristics with our previous CNTs based microbubble generators, we found that the power consumption of the CNCs based microbubble generator was one order lower than that of the CNTs based microbubble generator and 2~3 orders lower than that of traditional metal based microbubble generator.