Development of a piezoelectric pressure sensor based on highly aligned electrospun fibers and the optimization of Interdigitated Electrodes

• Main Authors: Jun-Yi Ke, 柯君逸
• Other Authors: 李世光
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/46352957022990986599

碩士 === 國立臺灣大學 === 應用力學研究所 === 105 === The goal of this thesis is to develop a highly sensitive and flexible piezoelectric pressure sensor for the application of wearable blood pressure. To create a high sensitivity and flexibility piezoelectric pressure sensor, the polymer-based piezoelectric P(VDF-TrFE) was chosen in this study. Electrospinning process was applied to electrospun P(VDF-TrFE) into an ultra-flexible thin-film like structure. Using electrospinning process with a rotating drum collector, fibers with different levels of alignment are created and studied. In order to enhance the sensitivity and prevent shortage between electrodes, inter-digitated electrodes (IDEs) were developed. Design parameters include gaps distance between electrodes, and orientations between IDEs and the direction of fiber alignments. Furthermore, the β crystal phase of P(VDF-TrFE) is optimized by studying its X-ray Diffraction (XRD) patterns under the conditions of annealing and corona discharge poling processes. It was found that the β phase can be enhanced and the sensitivity can be much improved by 1.92 ~ 5.84 times. Measurements of P-E curves are also conducted to verified the experimental findings. The maximum sensitivity was 15.21 nA/g by using bending test, and the lightest weight that can be measured is 0.1 g. Finally, it is verified that the developed thin-film piezoelectric pressure sensor can be used to measure the blood pressure signal on the skin near the carotid artery.