【作者】 佘勇；

【导师】 杨慕杰； 李扬；

【作者基本信息】 浙江大学 ， 高分子化学与物理， 2003， 硕士

【摘要】 本文采用自由基共聚的方法，制备了4-乙烯吡啶(4-vinylpyddine,4VP)和疏水性单体甲基丙烯酸丁酯(nbutyl methacrylate,nBuMA)的共I聚物(4VP-co-nBuMA)，及溴代正丁烷季胺化甲基丙烯酸二甲氨基乙酯与活性硅氧烷单体共聚物(MEBA-co-Si)，并采用红外光谱(IR)、元素分析等分析手段对合成的共聚物进行了表征。 以季胺化4VP-co-nBuMA为湿敏材料，制备了电阻型湿敏元件，研究了共聚物组成、季胺化时间、电极结构、制备工艺(浸涂时间、湿敏液浓度等)对湿敏元件响应的影响。发现：疏水性单元的引入，提高了湿敏元件的响应线性度和灵敏度；季胺化时间的延长，使聚合物季胺化程度提高，湿敏元件阻抗减小；电极叉指间距增大，阻抗增大。 以溴代正辛烷季胺化4VP-co-nBuMA为湿敏材料，制备湿敏元件，其具有响应线性度好、灵敏度高、响应快、高湿稳定性好等优点。以溴代正辛烷季胺化4VP-co-nBuMA(2／1)共聚物制得的湿敏元件在33％RH～97％RH内阻抗随湿度呈对数线性变化达4个数量级(10~7-10~3Ω)，湿滞小(＜2％RH)，灵敏度高，响应快(响应时间小于7秒)，高湿稳定性好：在高温(38℃)、高湿(87％RH～93％RH)环境下、通电(1KHz，200mV)72小时，元件响应变化较小。 采用1，4-二溴丁烷交联季胺化4VP-co-nBuMA共聚物，制备了交联型电阻湿敏元件。元件具有响应线性度好，灵敏度高，湿滞小、高温高湿稳定性好、耐无水乙醇有机溶剂性能好等优点。其中，交联季胺化17小时配料比为1／1共聚物湿敏元件，在33％RH～95％RH湿度范围内，阻抗变化达3个数量级(10~7-10~4Ω)，响应灵敏度高，几乎无湿滞。 以MEBA-co-Si共聚物为湿敏材料，制备了电阻型湿敏元件。其具有响应线性度好、灵敏度高、响应快等优点。通过与纳米ZnO无水乙醇胶体溶液共混，制备了有机无机纳米复合湿敏材料，并采用透射电镜(TEM)对复合湿敏膜进行了表征。复合后湿敏元件阻抗减小，响应线性度好，湿滞小(＜2％RH)，响应快，耐水性好：浸水(30min)前后响应几乎不变。 用静电吸引自组装法制备了聚苯乙烯磺酸钠(NaPSS)／聚二烯丙基二甲基氯化铵(PDDA)、NaPSS／溴代正丁烷季胺化聚4-乙烯吡啶(nBuBrP4VP)、聚苯乙浙江大学硕士学位论文 摘要烯磷酸钠则aPSS们化锌面OX聚丙烯酸钠p句／ZnO四个体系的自组装纳米复合湿敏膜及湿敏元件。采用紫外一可见光谱wV－VIS）、接触角测试、原子力显微镜（MM）等分析技术对纳米复合湿敏膜进行了表征，发现四个纳米自组装复合膜体系都是层层交替结构，ZnO纳米粒子均匀分散于有机／无机自组装膜中。 测试了不同体系湿敏膜的感湿特性，探讨了电极结构、感湿液浓度、离子强度／除闩电翻动复合膜层数、最外层材料、最内层材料等因素对湿敏元件响应特性的影响。发现：NaPSSrpDDA体系具有阻抗低、响应线性度好、湿滞小、响应快、灵敏度高等优点，其中双层数为25的湿敏元件在20％RH95％RH湿度范围内具有良好的线性响应，阻抗变化近4个数量级＊’l’Q卜灵敏度高。另外，发现将ZnO引入自组装体系可以加快湿敏元件的响应。 采用复阻抗谱分析法，利用Nyquist曲线和Bode模图初步探讨了交联4VPCO－nBOMA共聚物湿敏元件和自组装湿敏元件的感湿行为。更多还原

【Abstract】 Copolymers of 4-vinylpyridine(4VP) with nbutyl methacrylate(nBuMA) (4-VP-co-BuMA) and methacryloxyethyl butyl ammonium bromide with active organosilicone monomer (MEBA-co-Si) were prepared by radical copolymerization, and characterized by IR and element analysis.Resistive type thin film humidity sensors were prepared using quaternized 4-VP-co-BuMA as humi-sensitive materials, and the effects of composition of copolymer, quaternization time, electrode structures, technical parameters for preparation of sensors (including dipping time, concentration of dipping solution, etc.) on humidity response of sensors were investigated. It was found that introduction of hydrophobic monomer into polymer chain improved the response linearity and sensitivity, and the impedance of sensors decreased with longer quaternization time and shorter distance between electrode tracks.4-VP-co-BuMA quaternized with octyl bromide were found to be humi-sensitive material with good linearity, high sensitivity, fast response, high stability at high humidities. Sensors based on 4-VP-co-BuMA (4-VP/nBuMA=2/l) quaternized for 11 hours show good humidity response: Its logarithm of impedance varies linearly with relative humidity for four orders of magnitude(107-103 ) over the range of 33%RH~97%RH, showing high sensitivity, in addition, it exhibits fast response (response time less than seven seconds) and a small hysteresis(<2%RH). The response of sensors varied little after it was placed at high temperature(38癈), high humidity(87%RH~93%RH) with applied voltage of 200 mV for 72hours, which indicates the sensor has high stability under humid environment.Simultaneously cross-linked and quaternized 4-VP-co-nBuMA was also investigated as humidity sensing materials and showed good linearity, high sensitivity, good high stability at high humidity and high temperature, and durability to organic solvent, etc. Sensors based on 4VP-co-BuMA (VP/BuMA=l/l) with crosslinking and quaternization reaction of 17 hours exhibited a change of three orders of magnitude (104~107 ) in impedance over the range of 95%RH~30%RH, showing high sensitivity, and little hysteresis was observed.MEBA-co-Si was found to be humi-sensitive material with good linearity, highinAbstractsensitivity and fast response. Sensors based on nanocomposites of MEBA-co-Si with nanosized zinc oxide colloids was prepared, which show smaller impedance, good linearity, small hysteresis (<2%RH) and fast response (less than five seconds). Furthermore, its response changed little even after the sensor was soaked in water for 30 min.Four kinds of multi-layers nanocomposite humidity sensitive films, including sodium polystyrenesulfonate / poly(diallyldimethylammonium chloride) (NaPSS /PDDA), sodium polystyrenesulfonate/ poly4-vinylpyridine quaternized with butyl bromide (nBuBr-P4VP), sodium polysryrenesulfonate/zinc oxide(NaPSS/ZnO) and sodium poly(acrylic acid) /zinc oxide (PAANa /ZnO ), have been prepared by means of self-assembly. The UV -Vis spectra, contact angle test and AFM analysis indicated that all the films so prepared had a layer-by-layer structure. Transmission electron microscopy (TEM) analysis revealed that ZnO nanoparticles were equally distributed in the composite film.The humidity sensitive characteristics of these sensors prepared by means of self-assembly have been investigated and the effects of electrode structures, concentration of humi-sensing solution, number of bilayers, materials of the outer layer and inner layer on humidity response were discussed. It was found that self-assembly films of NaPSS/PDDA showed low impedance, good linearity and high sensitivity. Impedance of sensors with 25 bilayers of NaPSS/PDDA composite film changed linearly for four orders of magnitude (10 -10 Q) over the range of 20%RH~95%RH. Furthermore it was found that organic/inorganic nanocomposite films exhibit faster response than organic/organic composites.The humidity sensing behavior of sensors based on cross-linked and quaternized copolymer and the sensors based on nan更多还原