可量測小應變之可撓式壓電絲線開發及其在吞嚥訓練上之應用

Abstract

本論文旨在開發高靈敏度之可撓性壓電式應變感測器，以應用於人體喉部吞嚥時喉結在上升程度和確認舌骨的完整吞嚥來檢測吞嚥障礙和進行吞嚥訓練。為了使感測器具有高靈敏度和高可撓性，本研究選用聚(偏氟乙烯-三氟乙烯)的高分子壓電材料，使用滾筒收集器的標準靜電紡絲製程，在不同參數下製做出由數條微奈米絲線組成且具排列性之壓電絲線，觀察其微結構是由波浪狀和交叉狀兩種特徵存在於壓電絲線內，各設計了四種不同曲率和夾角的壓電絲線，利用有限元素模擬分析對不同表面形貌的壓電絲線給予10%的應變拉伸，觀察並比較其壓電輸出表現，為了提升絲線之機械性質，本研究探討了不同靜電紡絲製程參數對壓電絲線的機械性質影響，調整高壓電輸入值和針尖至收集器的距離以改變壓電絲線的排列性和幾何結構，利用掃描式電子顯微鏡觀察不同參數下的絲線表面結構，並對2組8種不同參數下所得之絲線做線性化製程，利用振盪器給予小幅度拉伸10％內之應變，做了為時3.5小時的重複拉伸，研究應變和壓電輸出結果之相關性，找出最適合應用於小形變之靜電紡絲製程參數，比較後選用3cm/10kV這組靜電紡絲製程參數絲線，其微結構下可看出為波浪狀，它擁有最佳線性度且回歸直線斜率為 -0.086，抗拉性實驗10%應變下也有很好的靈敏度0.27 N/%，將絲線結合TPU膜和銀線製做出壓電式應變感測器，並以此為基礎開發吞嚥感測器，設計三種不同尺寸之仿喉嚨裝置模擬吞嚥動作，成功比較出正常吞嚥和吞嚥障礙的喉頭抬升程度，並分辨三種不同曲率分別為3cm、2cm和1cm下正常吞嚥時喉頭抬升的訊號振幅，分別為7.5 V、6.8V和5.0V。最後實際貼附於人體喉嚨表面，成功量測到正常吞嚥下喉頭抬升的訊號，且可分辨出吞嚥5 ml、10 ml和20 ml的水訊號振幅分別為1.45 V、1.77 V和2.62 V，另外量測將感測器貼附於舌骨處，成功量測到一個完整確實吞嚥的訊號，且根據傅立葉轉換來分辨出吞嚥5 ml、10 ml和20 ml的水，證明此吞嚥感測器對於吞嚥訓練有其可行性。

The aim of this paper is to develop a flexible piezoelectric strain sensor with high sensitivity. It can be attached to the skin of larynx for the application of dysphagia detection and swallow training. To make the sensor have a high sensitivity and flexibility, poly(vinylidenefluoride-co-trifluoroethylene) piezoelectric polymer is used, and the standard electrospinning process of the roller collector was used to produce microfibers with different arrangement by using different spinning parameters. It is found that the surface morphology consists of wavy and cross-shaped features in the piezoelectric wire. The finite element simulation analysis is used to study the structure deformation of microfibers under 10% stretching strain, and it shows that the piezoelectric output performance is nearly linear with the mechanical strain. In order to improve the mechanical performance of the piezoelectric strain sensor, we explore the effects of electrospinning parameters on the mechanical properties of the piezoelectric microfibers and analyze the microstructure with a scanning electron microscope. The contribution of alignment process is also investigated. It is found that the optimal microstructure of the piezoelectric microfiber is wavy-shaped. It has a good elasticity and linearity with a sensitivity of -0.084 after a 3.5 hours alignment process. Using these piezoelectric microfibers, we develop a piezoelectric strain sensor that can be attached to the skin of larynx by using elastic thermoplastic polyurethane and silver wires. Three different sizes of throat-like devices are designed to simulate the swallowing action, and the waveform performance of normal swallowing and dysphagia is successfully compared, and the amplitudes of the signals with swallowing at 3cm, 2cm and 1cm are resolved, which are 7.5 V ,6.8 V and 5.0 V respectively. Finally, the sensor is attached on the skin of larynx. The movement of larynx was successfully measured. In addition, the sensor is attached to the hyoid bone, and the signal of swallowing also was successfully measured. This sensor also can distinguish different volume of water in frequency domain by using Fourier transform. In summary, the feasibility of the developed swallowing sensor is verified.