本研究結合溶膠-凝膠法(Sol-gel method)、自由基聚合反應(Free radical polymerization)和自組裝技術(Self-assembly technique)合成具有三功能官能基的有機矽高分子後並以金奈米粒子修飾之而製備出新型的可撓式濕度感測器。
製備具有三功能官能基之有機矽高分子聚合物,首先將3-(三甲氧基甲矽烷基)丙基丙烯酸酯(TMSPMA)以溶膠-凝膠法以矽氧鍵結修飾於(3-巰基丙基)-3-甲氧基矽烷(MPTMS)上,接著以自由基聚合反應將親水性聚電解質的(3-甲基丙烯醯胺基丙基)三甲基氯化銨(MAPTAC)以化學鍵結方式修飾MPTMS-TMSPMA凝膠,最後將金奈米粒子以自組裝技術修飾在MPTMS-TMSPMA-MAPTAC網狀結構的硫醇基上。以傅立葉轉換紅外線光譜儀(FTIR)和掃描式電子顯微鏡(SEM)探討Au NPs/MPTMS-TMSPMA-MAPTAC複合材料膜之有機矽聚電解質高分子鍵結情況和其材料表面特徵。
Au NPs/MPTMS-TMSPMA-MAPTAC複合材料中的硫醇官能基和中孔洞二氧化矽骨架可以增加濕度感測器薄膜在高濕度環境中的穩定性,親水性的官能基作為感濕主導材料提供水氣的活性位點,金奈米粒子可增加複合材料的導電性。本研究的可撓性濕度感測器具有高靈敏度、可接受的線性、濕滯現象小、反應時間短和工作範圍大。另外將利用阻抗分析頻譜探討Au NPs/MPTMS-TMSPMA-MAPTAC複合材料膜的感濕機制是由水合氫離子(H3O+)為主導。
A novel flexible humidity sensor based on gold nanoparticles (Au NPs) and three reactive func-tional groups-containing organosilica was fabricated by a combination of sol–gel process, free radical polymerization, and self-assembly technique. The three reactive functional groups-containing organosilica was firstly prepared via modifying the (3-mercaptopropyl) tri-methoxysilane (thiol-MPTMS) with 3-(trimethoxysilyl)propyl methacrylate (vinyl-TMSPMA), and a hydrophilic polyelectrolyte [3(methacryloylamino)propyl] trimethyl ammonium chloride (MAPTAC) was modified onto the MPTMS-TMSPMA gel. The Au NPs were assembled onto the thiol groups of the MPTMS-TMSPMA-MAPTAC gel network. The composition and microstructure of the Au NPs/MPTMS-TMSPMA-MAPTAC composite film was characterized by Fourier transform infrared spectroscopy (FTIR) by and scanning electron microscopy (SEM). Thiol groups and mesoporous silica skeletons could ensure the stability of the humidity-sensing film on substrate at high humid environment and hydrophilic groups behave as humidity sensitive sites. This flexible humidity sensor also had a high sensitivity, an acceptable linearity, a small hysteresis, a short response time in wide range of working humidities. Based complex impedance spectra analysis, the ions (H3O+) in this system dominate the conductance process of the flexible humidity sensor.