【作者】 李朋；

【导师】 李扬； 杨慕杰；

【作者基本信息】 浙江大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 本论文设计合成了含硅聚电解质、超支化聚羧酸盐及其与纳米氧化锌复合物、超支化聚季胺盐等三种湿敏材料,采用¹H-NMR、FT-IR、TGA、SEM、TEM、AFM等方法表征其组成和形貌结构。分别通过静电纺丝法、溶液浸涂法和静电喷涂法制备了薄膜电阻型和声表面波（SAW）型湿敏元件,并研究了其在室温下的湿敏响应特性,以及对于溶剂中水分的电响应特性。采用静电纺丝法,制备了具有交联结构的含硅聚电解质及其与聚苯胺和聚吡咯等复合纳米纤维电阻型湿敏元件,测试了其响应灵敏度、响应时间、湿滞等湿敏响应行为。研究了电极修饰、成膜方法、复合等对于元件湿敏响应特性的影响。制备的含硅聚电解质与聚苯胺复合纳米纤维湿敏元件在22-97%RH较宽的湿度范围内,阻抗从10⁷Ω变化为10⁴Ω,体现了较高的响应灵敏度,在半对数坐标下良好的响应线性度（R²=0.979）,以及快速响应（吸湿7s,脱湿19s）和很小的湿滞（1.6%RH）。采用静电喷涂方法,在单端延迟线型声表面波器件表面沉积含硅聚电解质敏感膜,制备了SAW型湿敏元件。研究了喷涂液浓度,喷涂时间等对于SAW元件的湿敏响应特性影响。制备的湿敏元件在11-97%RH的湿度范围内,具有快速（吸湿、脱湿时间均小于10s）、灵敏度较高（400Hz/%RH）、且响应重复性和高湿环境下稳定性较好等优点。以超支化结构聚酯为核,制备了含有不同碱金属离子（Li⁺,Na⁺,K⁺）的阴离子型超支化聚羧酸盐湿敏材料（HBPC）,并与氧化锌纳米棒以及纳米粒子复合,制备了有机/无机纳米复合湿敏材料。AFM测试显示纳米氧化锌在复合材料中分散良好。采用浸涂法制备了超支化聚羧酸盐及其与纳米氧化锌复合电阻型湿敏元件,研究其湿敏响应特性。发现碱金属离子类型对元件的湿敏性能影响很大;而与纳米氧化锌复合,减小了元件的湿滞,加快了响应,提高了湿敏响应特性。以超支化结构聚酯H20为核,制备了阳离子型超支化聚季铵盐湿敏材料,采用浸涂法制备了电阻型湿敏元件。对比了其与典型的线型聚电解质湿敏材料（PDMAEM-BB）以及聚合物/金属盐复合湿敏材料（PEO/LIClO₄）的湿敏响应特性。发现超支化聚季胺盐湿敏材料在低湿下阻抗较低,具有很宽的湿度检测范围（5-96%RH）,而且湿滞很小（1.1%RH）,响应速度很快（吸湿8s,脱湿9s）,响应灵敏度高,具有最佳的湿敏响应特性。这可能与其超支化结构相关。以具有交联结构的含硅聚电解质为敏感材料,采用浸涂法制备了电阻型敏感元件,研究了其在不同极性的有机溶剂中对不同含量水分的响应灵敏度、响应时间、检测限等响应特性,初步探讨了其在检测有机溶剂中水分含量方面的应用。更多还原

【Abstract】 Three kinds of humidity sensitive materials, namely, silicon-containing polyelectrolytes, hyperbranched polycarboxylates and their composites with nano-sized ZnO, and hyperbranched quartemary ammonium salts were prepared and characterized by ¹H-NMR, TGA, SEM, TEM, FT-IR. They were used to construct resistive type and surface acoustic wave （SAW） type humidity sensors by different film-forming methods including electrospinning, dip-coating, electrospraying. Their humidity sensitive properties have been investigated. Moreover, the electrical response to water content in organic solvent of the silicon-containing polyelectrolytes was explored.Resistive-type humidity sensors based on nanofibers of a composite of silicon-containing polyelectrolyte were obtained by electrospinning. Their humidity sensitive properties such as sensitivity, sensing linearity and hysteresis were measured. It was found that the polymer composite nanofibers showed impedance change from 10⁴ to 10⁷Ωwith the increment of relative humidity （RH） from 22 to 97% at room temperature, exhibiting high sensitivity and good linearity （ R² = 0.979 ） on a semi-logarithmic scale. In addition, they exhibited fast and highly reversible response as characterized by small hysteresis （1.6%RH） and short response time （7 s and 19 s for adsorption and desorption, respectively）.SAW type humidity sensors were obtained by electrospraying the silicon-containing polyelectrolyte onto the surface of a single-port surface acoustic wave sensor with a resonance frequency of 433 MHz. The effects of concentration of the electrospray solution and electrospray time have been discussed. Preliminary experimental results showed that the humidity sensor had wide detection range from 10% to 97% RH, high sensitivity of 400Hz/%RH, rapid response time （less than 10s） and excellent durability under high humidity.Thin film resistive-type humidity sensors based on hyperbranched polycarboxylates （HBPC） with different alkali metal cations （Li⁺, Na⁺, K⁺） and their composites with ZnO nanorods and ZnO colloids were fabricated by the method of dip-coating. The morphologies of films of HBPC and the composite were investigated by AFM, which revealed uniform distribution of nano-sized ZnO in HBPC. It was found that the type of cations greatly affected the humidity sensing behaviors of HBPC. Moreover, the nanocomposites of HBPC and ZnO exhibited smaller hysteresis and faster response as compared to HBPC alone.Thin film resistive-type humidity sensors based on hyperbranched quaternary ammonium salts materials were constructed by the method of dip-coating. It was revealed that the sensor exhibited excellent humidity sensitive properties: wide humidity detection range （5-96%RH）, small hysteresis （1.1%RH）, fast response （absorption time:8 s, desorption time:9 s） and good sensing sensitivity . In comparison, the typical humidity sensitive materials of linear quaternary ammonium salts （PDMAEM-BB ） exhibited narrower humidity detection range （20-96%RH）, while the salt doped polymer （ PEO/LIClO₄） showed large hysteresis （5.3%RH） and slow response （absorption time: 39s, desorption time: 118s）The electrical response of silicon-containing polyelectrolyte to water content in different organic solvents was explored, including sensitivity, detection limit, hysteresis, dynamic sensing behaviors and durability.更多还原