【作者】 庄馥隆；

【导师】 程秀兰；

【作者基本信息】 上海交通大学 ， 微电子学与固体物理学， 2010， 硕士

【摘要】 近年来结构性建筑大量增加,提高这些建筑的安全检测水平十分重要。计算机实时评估系统可以大大推进桥梁的健康检测水平,而由大量传感器组成的传感网络则是建立该系统的基础。能适应外界环境变化并且可以安装在不平整表面上的柔性应变传感器是未来发展的趋势。其中碳纳米管薄膜传感器由于具有优异的性能而成为研究热点,目前已有不少相关报道。但是,基于柔性基底的碳纳米管薄膜应变传感器的相关研究主要集中于国外,而且大多数研究针对的是刚性基底。并且现有的碳纳米管应变薄膜研究,大多未考虑薄膜对工作环境的适用性。本文设计并制作了一种用于结构健康监测的柔性碳纳米管薄膜应变传感器,对传感器敏感元碳纳米管薄膜的性能进行了探讨,对应变传感器的应变响应性能和稳定性能进行了研究。利用层层自组装(Layer-by-layer, LBL)方法在柔性基底聚乙烯膜上制备了单壁碳纳米管网状薄膜,并对其进行了SEM、AFM薄膜表面形貌表征。测试了薄膜电性能,探讨了碳纳米管薄膜的导电机理,并分析了关键工艺因素对薄膜电性能的影响以优化LBL工艺。试验表明碳纳米管薄膜有良好的电导性,12层薄膜的电阻率为1.47×10-9M?·m;薄膜的电阻随着层数的增加呈指数态下降,电阻率越来越低;改变PDDA(poly (dimethyldiallylammonium chloride)浓度或碳纳米管浓度亦对薄膜导电性能有较大影响。测试了薄膜透光性。采用层层自组装碳纳米管薄膜及微细加工工艺,在柔性衬底上制备了应变传感器。该传感器通过输出薄膜电阻反映应变大小。测试了器件对压应变和拉伸应变的不同响应情况,器件对应变呈现较好的敏感性、快速响应特性、线性响应和可恢复性,灵敏度为4.25。研究了湿度和光照等因素对器件信号的影响,试验表明添加防护层能有效减少外界湿度和光照因素影响,传感器稳定性明显提高。探讨了应变传感机理及外界因素的影响机制。该传感器由于在柔性基底上制作,可用于桥梁等结构设施中弯曲表面的应力应变检测。更多还原

【Abstract】 Recently lots of bridges and tunnels are being developed, and the security evaluating for these structures is very important. Computer in-time evaluating system has many advantages at this field, the basic of which is Sensor network system. Therefore, flexible strain sensors being able to endure the environmental changes and to be used on curved surfaces become the development trend. And sensors based on CNT thin films become a hot subject branch because of their excellent properties, which have been studied by many researchers. But related researches are mostly carried out by foreigners, and most of those researches focus on rigid substrate. And little studies is reported to analyze the applicability of CNT thin film strain sensor in different environment.This essay designed and manufactured a kind of strain sensor that is used for structure health monitoring and based on single-walled carbon nanotube network thin films deposited on flexible polyethytlene film with layer-by-layer self-assemble method. And both the films and the sensors were characterized.SWNT network thin films were developed on flexible substrate PET with layer-by-layer (LBL) self-assembly. Then the films were characterized by SEM and AFM and tested by electricity measuring devices. The mechanism of film conductivity is analyzed, and the key process factors are optimized. The experimental data show the CNT films are with good electric conductivity property, and the resistivity of CNT film of 12 layers is 1.47× 10-9M?·m. The resistance of the films will decay exponentially with the increase of layers. The affect of changing the concentration of PDDA(poly (dimethyldiallylammonium chloride) and SWNT was also measured. The light transmittance properties of these films were also tested.Strain sensors were manufactured with LBL self assembly CNT film by microelectronic process on flexible substrate. The sensors output different resistance for different strain with prompt and nearly linear response, as well as they achieve their strain sensitivity up to 4.25. The response of the sensor to tensile strain and compressive strain are all tested. Stability is evidently improved by adding protective coating on the surface of the devices, with which devices become less vulnerable to humidity and illumination. The piezoresistive effect of the CNT films and the mechanism of the affect of humidity and illumination to CNT films are discussed. These flexible sensors can be used on curved surfaces of bridges and other buildings to test stress and strain because of their flexible substrates.更多还原