Charge-storage mechanisms in solution-based processing of electret and its application for a flexible electrostatic actuator
| Autor: | Wen-Ching Ko, 柯文清 |
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| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 Recent futuristic applications of flexible electret loudspeakers have garnered much interest for these novel loudspeakers. In this study, a novel thin film processing method was developed to improve the performance of an electret diaphragm. Taking a thin porous polytetrafluoroethylene (PTFE) film as the base material, a cyclic olefin copolymer (COC) was coated to a base material to form a composite PTFE/COC film. Results show that the composite material improves the advantageous characteristics such as Young’s modulus, charge stability and charge density, etc., when used as an electret diaphragm for loudspeakers. In addition, a micelle formation of processing method was developed to improve the performance of an electret diaphragm in this study. A COC thin film containing an additive such as 2-(6-mercaptohexyl) malonic acid and derivatives was prepared using a spin-coating process. We discuss the relationship between the charge storage and the additive concentration of the COC+additive thin film. Furthermore, attention was directed towards the processing conditions which were found to have an important role and is related to the self-assembly and micelle formation behavior of the additives in the COC. Compared with a reference thin film of pure COC, results indicated that when a 3497mg/kg 2-(6-mercaptohexyl) malonic acid was added to the COC matrix, the obtained surface potential was 71% higher. Thus, the results show that a COC+additive thin film leads to a much improved charge storage. It appears to be an inexpensive and relatively easy way to form an improved thin electret diaphragm. Experimental results were shown to demonstrate that we have successfully created a laminar structure and fabricated the flexible electret loudspeaker. The cell actuators needed to form an array structure were also presented. The novel sound generating techniques presented were suitable for futuristic audio system, which included energy-saving, flexible structure, easy to fabricate in large area, and high degree of design freedom, etc. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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