結合PVDF/PTFE微結構與無線傳輸之布基摩擦起電元件的研製

Triboelectric generators (TEGs) can convert mechanical energy into electrical energy in the environment, which can be stored in capacitors to supply the action of devices, which is beneficial to the self-powered wearable electronic products. However, at present most substrate materials used in flexible TEGs are mainly polymers, on which micro/nano structures are fabricated to increase the friction effect. The electrode materials mainly use metals and ITO films, but the poor flexibility of these materials limits the TEG applications. Although there have been researches using graphene, carbon nanotubes or silver nanowires to prepare thin-film electrodes to achieve high-bended deformation, there still some problems exist such as high cost and complicated manufacturing process. Therefore, this project will directly use conductive fabrics as substrates and electrodes, and then arrayed micronstructures fabricated on the fabric surface to increase the friction effect with high electronegativity materials (PVDF and PTFE). PVDF and PTFE can combine with human skin of electropositivity to achieve maximum electrical output. It is expected that a single-electrode fabricbased TEG device with an area of 40×40 mm2 can realize 180° bending and the optimal open-circuit voltage and short-circuit current exhibit performance values of 28.41 V and 0.32 μA, respectively. The main points of implementation and works of the overall plan include: (1) Fabrication of microstructured PVDF/PTFE friction layer: Using the MEMS process and combining techniques, three different sizes of PVDF and PTFE/PVDF positive pyramid array structures of 25 μm, 50 μm and 75 μm will be fabricated on the surface of the conductive fabric. (2) Surface modification of friction layer: PVDF, PVDF/PTFE, PVDF/GO friction layers are treated with CF4 plasma modification, and C-F functional groups are applied to the surface of the friction layer to improve the electronegativity and friction of the friction layer structure. (3) Packaging of fabric-based TEG devices: The PVDF and PVDF/PTFE friction layers will be attached to the conductive fabric of 40×40 mm2, and combined with the copper foil tape as the output, the fabrication of the single-electrode fabricbased triboelectric element can be completed. (4) Evaluate self-power and pressure sensing performance: The completed fabric-based TEG element has both the self-powering function of the pressure sensor and the triboelectric generator. (5) Circuit design of wireless transmission module: Using analog circuits and analog-to-digital converters, in conjunction with Arduino and wireless transmission modules, the sensed pressure/vibration signals are transmitted and displayed on mobile devices or cloud-based applications. (6) Application evaluation of wearable TEG devices: Feasibility evaluation of triboelectric electrification and pressure sensing will be conducted. Including attaching to the mechanical vibration component, performing capacitor storage to light the LED array bulb, eighteen green LED bulbs connected in series can be illuminated. At 50 MΩ load resistance, the output power is 12.91 μW. After passing 20,000 cycle tests, the output characteristics dropped from the original 19.79V to 14.2V, with a retention rate of 87.8%.