【作者】 吕鑫；

【导师】 杨慕杰；

【作者基本信息】 浙江大学 ， 高分子化学与物理， 2008， 博士

【摘要】 本论文共设计制备了四个系列共八种新型高分子湿敏材料:含硅聚电解质湿敏材料;季铵盐类聚电解质湿敏材料;吡咯基聚电解质湿敏材料;超支化聚合物湿敏材料。聚合物湿敏材料的制备是采用溶胶-凝胶、自由基共聚、紫外光辐射、接枝、原位生长等方法。并且,采用FT-IR、NMR、TGA、TEM、SEM、UV-Vis等手段对其组成和结构进行了表征。通过浸涂及静电纺丝方法在金叉指电极表面成膜,制备了湿敏元件。研究了湿敏元件的感湿特性,讨论了元件敏感层的组成、结构,微观形貌,及其制备工艺条件等因素对湿敏元件响应性能的影响,探讨了湿敏材料的感湿机理。利用溶胶-凝胶反应制备了具有交联结构的3-氨丙基三乙氧基硅烷季铵盐(APTS-BB)湿敏材料。考察了聚合物组成,预聚液浓度,季铵化试剂种类,以及制备工艺(季铵化时间,预聚液陈化及加热交联时间,电极结构)对湿敏元件感湿特性的影响。所制备的元件具有制备简便(一步法),响应灵敏度高(在97-11%RH相对湿度测量范围内,阻抗值变化四个数量级:10~3-10~7Ω),响应线性度好(R~2=0.977),湿滞小(1.1%),响应速度较快(吸湿30.1s,脱湿34.8s)等优异的性能,而且还具备良好的耐高温高湿,耐水,及耐溶剂特性。通过交流复阻抗谱分析,其湿敏行为与典型的聚电解质湿敏材料相一致,导电机理主要为离子导电。采用自由基聚合,制备了季铵盐/聚醚共聚湿敏材料。考察了聚醚/季铵盐共聚比例、掺杂盐含量、掺杂盐种类对湿敏元件感湿特性的影响。该元件具有极宽的湿敏响应区间(0-97%RH),极佳的响应线性度(R~2=0.997),以及较高的灵敏度(三个数量级:10~3-10~6Ω),较小的湿滞(1.6%RH)和较快的响应速度(吸湿48.6s,脱湿23.4s)。此外,该元件即使在～0%RH下,其依然保持了导电性(阻抗值:10~6Ω),可应用于低湿环境下湿度的监测。采用紫外光辐射法制备了具有交联结构的季铵盐-二乙烯基苯(PDB-DVB)湿敏材料。考察了季铵盐/二乙烯基苯共聚比例,交联剂种类,季铵盐基团预聚与否,紫外光辐射时间对湿敏元件感湿特性的影响。所制备的元件响应灵敏度高(97-22%RH测量范围内,阻抗值变化三个数量级:10~3-10~6Ω),响应线性度好(R~2=0.959),湿滞小(1%),响应速度快(吸湿9.1s,脱湿31.7s)。紫外光辐照交联法制备工艺简便(低温:＜60℃,周期短:＜1h),同时制备的元件具有较好的耐水性。采用接枝、氧化聚合的方法,制备了基于吡咯的聚电解质湿敏材料。考察了预聚液浓度、羧酸盐种类对湿敏元件感湿特性的影响。元件在0-97%RH测量范围内,阻抗变化两个数量级:10~4-10~6Ω,线性度为:R~2=0.988,具有快的响应速度(吸湿12.5s,脱湿15.2s)以及小的湿滞(4.7%RH)。元件在低湿(～0%RH)下仍具有电导性(阻抗值:10~6Ω),可以应用于低湿环境下相对湿度的检测。此外,对湿敏元件在低湿、高湿下的湿敏响应特性进行了研究,探讨了其湿敏机理。该湿敏元件同时具备电子及离子两种导电机制。以超支化聚酯H20为核,制备了具有超支化结构的羧酸盐以及季铵盐湿敏材料。考察了端基接枝种类、接枝数量及超支化结构对湿敏元件感湿特性的影响。元件在97-11%RH测试范围内,具有高的响应灵敏度(阻抗值变化三个数量级:10~3-10~6Ω),响应线性度为:R~2=0.902,小的湿滞(1%RH),以及较快的响应速度(吸湿9.08s,脱湿9.46s)。与线形聚合物湿敏材料相比,超支化季铵盐材料的阻抗值较低,湿敏响应范围较宽。利用熔融缩聚的方法制备了具有超支化结构的聚酰胺湿敏材料(HBPA)。通过季铵化反应可以提高材料的湿度敏感性,但材料的响应线性度有所下降。纯HBPA材料在低湿下阻抗值较高,通过共混、接枝两种方法将碳纳米管引入HBPA体系,有效降低了HBPA在低湿环境下的阻抗,扩大了其湿敏响应区间。探索了含硅聚电解质APTS-BB湿敏元件在有机溶剂微量水分测试中的应用,研究了元件在不同极性、不同水含量溶剂中的湿敏特性,及其动态敏化行为,并提出了相应的机理。采用静电纺丝的方法制备了APTS-BH纤维状湿敏材料,初步研究了纺丝液配比,纺丝时间,纺丝电压对元件感湿特性的影响。较之薄膜材料,纤维状湿敏材料的响应速度大大提高。更多还原

【Abstract】 Four types of polymer humidity sensitive materials were designed and prepared, including silicon-containing polyelectrolytes,quaternaray ammonium salt polyelectrolytes,pyrrole based polyelectrolytes,and hyperbranched polymer humidity sensitive materials.These materials were synthesized by sol-gel,radical copolymerization,UV irradiation,graft,and in-situ polymerization method,respectively, and characterized by FT-IR,NMR,TGA,TEM,SEM,UV-Vis.Resisitive type humidity sensors were prepared by forming film on the interdigital gold electrodes with dip-coating and electrospinning methods.The humidity sensitive properties of the sensors have been investigated.The effects of the composition,structure and morphology of the sensitive films,preparation techniques on the sensing characteristics of the humidity sensors were discussed.The humidity sensitive mechanisms were explored.The 3-aminopropyltriethoxysilane quaternary ammonium salt（APTS-BB） humidity sensors with cross-linking structure were prepared by sol-gel method.The effect of component of the polymers,concentration of dip-coating solution,type of quaternization reagent,and the preparation techniques（quaternization reaction time, aging and cross-linking time of precursor solution,and electrode structures） on the humidity sensitive properties of sensors have been investigated.The sensors easy prepared（one-pot method） and exhibited high sensitivity（the impedance change from 10³ to 10⁷Ωin the range of 97%-11%RH）,good linearity（R²=0.977）,small hysteresis （1.1%RH） and last response（adsorption time 30.1s,desorption time 34.8s）. Furthermore,it was featured with good durability to high temperature and high humidity, and high resistance to water and solvents.The investigations on the humidity sensitive mechanism by complex impedance spectra revealed that the polymer showed sensing characteristics typical of polyelectrolytes,and ion conductivity in its conduction behavior. Copolymers of quaternary ammonium salt with polyether were prepared by radical copolymerization.The effect of ratio of methyl ether methacrylate/2-（dimethylamino） ethyl methacrylate quaternary ammonium salt（PEGMEMA/DB）,doped content of NaClO₄,and type of doped salt on the humidity sensitive properties of sensors were investigated.The sensors prepared exhibited very wide sensitive range（0-97%RH）, excellent linearity（R²=0.997）,high sensitivity（10⁶-10³Ω）,small hysteresis（1.6%RH） and fast response（adsorption time 48.6s,desorption time 23.4s）.Furthermore,the sensors maintained high conductivity even at very dry atmosphere,are promising to detect low humidity.Humidity sensors based on cross-linked quaternary ammonium salt were fabricated by UV irradiation method.The effect of ratio of poly[2-（dimethylamino） ethyl methacrylate quaternary ammonium salt]/divinyl benzene（PDB/DVB）,type of crosslinking agent,prepolymerization of 2-（dimethylamino） ethyl methacrylate quaternary ammonium salt（DB）,and irradiation time on the humidity sensitive properties of sensors were investigated.The sensors prepared exhibited high sensitivity （the impedance change from 10³ to 10⁶Ωin the range of 97%-22%RH）,good linearity （R²=0.959）,small hysteresis（1%RH） and fast response（adsorption time 9.1s, desorption time 31.7s）.The whole manufacture procedure was processed in low temperature（≤60℃） and can be accomplished in an hour.In addition,the sensors exhibited excellent durability against water.Pyrrole based polyelectrolytes（PY-PE） humidity materials were prepared by graft and oxidation polymerization.The effects of concentration of precursor solutions and type of carboxylic salt on the humidity sensitive properties of sensors were investigated. The sensors exhibited an impedance change of 10⁴-10⁶Ωin the range of 97%-0%RH, good linearity R² of 0.988,hysteresis of 4.7%RH and fast response（adsorption time 12.5s,desorption time 15.2s）.The sensors maintained conductivity even at very low humidity atmosphere（～0%RH）,which are promising to detect low humidity. Furthermore,the difference of sensitive behavior of sensors at low and high humidity atmosphere were investigated,the humidity sensitive mechanisms were explored.The sensor based on PY-PE exhibits both ionic and electronic conduction contributed to its conductivity.The humidity sensitive properties of hyperbranched polyester（H20） whose terminal hydroxyl group was converted to carboxylic salt and quaternary ammonium salt group have been investigated.It was found that the type and number of terminal groups,the hyperbranched structure can affected the humidity sensitive properties of H20 based sensors.The sensor prepared exhibited high sensitivity（the impedance change from 10³ to 10⁶Ωin the range of 97%-11%RH）,linearity R² of 0.902,small hysteresis（1%RH） and fast response（adsorption time 9.08s,desorption time 9.46s）.Compared with linear polymer humidity sensitive material,hyperbranched humidity sensitive material exhibited lower impedance and wider humidity measurement range.Hyperbranched Polyaniline HBPA was prepared by melt polycondensation.The sensitivity of HBPA can be improved by quaternized with n-butyl bromide or dibromobutane;however its linearity was decrease.Through mixing or grafting CNT into the HBPA can decrease the impedance of the sensors at dry atmosphere and broad its humidity measurement range.The applications of APTS-BB humidity sensor in the water detection of organic solvents have been explored.The humidity sensitive properties of sensors in the solvents with different polarity and water content,and dynamic sensing behaviors were investigated;the humidity sensitive mechanisms were explored.APTS-BH fibre humidity sensors were prepared by electrospining method.The effects of composition of electrospining solution,electrospining time,and electrospining voltage on the humidity sensitive properties of sensors were described.Compared with thin film material,the fibre material increased the response speed of the sensors.更多还原