【作者】 罗峰；

【导师】 陈显平；

【作者基本信息】 重庆大学 ， 仪器科学与技术， 2021， 硕士

【摘要】 随着全球亚健康的问题日益严重,近年来人们对健康实时监测的关注越来越广泛,且开发出越来越多的具有健康监测功能的可穿戴设备,但是这些设备大都采用刚性的传感器和结构部件,不利于穿戴的舒适性。基于柔性应变传感器的可穿戴电子由于其高柔韧性、可拉伸性、皮肤保形贴合特性和高灵敏度等优势被广泛研究,该柔性应变传感器主要由柔性衬底和导电应变敏感材料组成,因此通过对柔性衬底的改性和应变敏感材料的设计,可以实现可调控的高灵敏度和宽应变范围的特性。本文主要是采用激光雕刻碳前驱体的工艺,快速制备高质量的三维多孔状的石墨烯(laser-induced graphene,LIG)材料,通过对碳前体衬底材料的设计,可以得到高柔性甚至是高可拉伸的应变传感器。本文的具体内容如下:(1)在商用聚酰亚胺(polyimide,PI)薄膜碳前体表面,通过激光雕刻方式直接生成图案定制化的敏感材料LIG,进而可制备出基于PI衬底的双功能自报警的电子皮肤。首先研究了激光雕刻的功率参数和不同图案化的LIG对制备的应变传感器和热声器件的性能影响,得出了在6.6%激光功率下制备的百叶窗图案化的传感器具有最佳的力学和声学的综合性能。当电子皮肤工作于应变传感器模式时,得益于其优异的压阻特性,获得了316.3的超高灵敏度,有利于生理健康信号的实时监测,例如呼吸、语音和手腕脉搏等。当应变传感器检测到异常信号时,可以切换成发声报警模式,使其拥有59 d B的声压级和200 Hz-20 k Hz的超宽频谱响应。基于PI衬底和LIG材料制备的电子皮肤将健康监测与发声报警功能集成到单一的器件中,实现了睡眠呼吸暂停综合症等突发疾病的实时监控预警。(2)由于商用PI薄膜的高模量,使得制备的应变传感器的可拉伸性能较差,因此开发出基于聚乙烯醇(PVA)可拉伸衬底的LIG应变传感器。首先研究甘油增塑剂对PVA薄膜的拉伸性能(最大可拉伸663%)的改善,再在PVA薄膜中掺杂碳前体PI粉末,进一步调控PVA/PI薄膜的模量。通过对在低模量的PVA薄膜上层压的不同模量、尺寸的PVA/PI薄膜的力学研究,得出上下层薄膜的模量相当时可制备出高拉伸性能的传感器,当PVA/PI模量远大于PVA模量时可得出应变不敏感的传感器构型。因此,基于可拉伸的PVA/PI薄膜构型可制备出宽应变范围的应变传感器,通过结合蛇形弯的银纳米线导电互连线,制备了可拉伸18%应变、高线性度和高灵敏度(约44.7)的应变传感器。得益于其在灵敏度和应变范围所具备的双重优异性能,可被用于人体生理健康信号的实时监测和运动肢体行为的检测。更多还原

【Abstract】 With the global sub-health problem becoming more and more serious,real-time health monitoring has attracted tremendous attention in recent years,and more and more wearable devices with health monitoring functions have been developed.However,most of these devices are composed of rigid sensors and structural components,which is not conducive to the comfort of wearing.Wearable electronics based on flexible strain sensors have been widely studied due to their advantages of high flexibility,stretchability,skin conformality and high sensitivity.The flexible strain sensors are mainly composed of the flexible substrate and conductive strain-sensitive materials.Therefore,through the modification of flexible substrate and the design of strain-sensitive materials,the tunable properties of high sensitivity and wide strain range can be achieved.In this thesis,highquality three-dimensional porous laser-induced graphene(LIG)materials are rapidly prepared by laser engraving of carbon precursors.Through the design of carbon precursor substrate,high flexibility and even high stretchable strain sensors can be obtained.The specific contents of this thesis are as follows:(1)By using the laser-induced method to directly generate a patterned strainsensitive material LIG on the surface of commercial polyimide(PI)film,a dualfunctional self-alarm electronic skin(e-skin)based on PI substrate can be prepared.Firstly,the influence of laser power parameter and different patterned LIG on the performance of strain sensors and thermoacoustic devices is studied.It is concluded that the shutter patterned e-skin prepared under the 6.6% laser power has the best mechanical and acoustic performance.When the electronic skin works in the strain sensor mode,it achieves a high sensitivity of 316.3 thanks to its excellent piezoresistive characteristics,which is conducive to the application of real-time detecting of physiological health signals,such as breathing,human voice and wrist pulse.When the strain sensor detects some abnormal signal,it can switch to the audible alarm mode,so that it possesses the sound pressure level(SPL)of 59 d B and an ultra-wide spectrum response of 200 Hz-20 k Hz.The electronic skin based on PI substrate and LIG material integrates health monitoring and self-alarm functions into a single device to realize real-time monitoring and early warning of sudden diseases such as sleep apnea.(2)Due to the high modulus of commercial PI film,the tensile property of the prepared strain sensor is poor.Therefore,the tensile strain sensor based on the stretchable polyvinyl alcohol(PVA)film substrate and conductive LIG material is developed.Firstly,the improvement of tensile properties(maximum over 663%)of PVA film by glycerol plasticizer was studied.Then,carbon precursor PI powder was doped into PVA film to further regulate the modulus of PVA/PI film.Through the mechanical optimization of PVA/PI films with different modulus and size welded on low-modulus PVA films,it is concluded that the sensor with high tensile properties can be prepared when the modulus of the upper and lower films is equal,and the sensor configuration with strain-insensitive can be obtained when the modulus of PVA/PI films is much greater than that of PVA films.Therefore,the strain sensor with a wide strain range can be fabricated based on the stretchable PVA/PI film configuration.So,the strain sensor with the strain of 18%,high linearity,and high sensitivity(about 44.7)can be fabricated by combining the serpentine bend Ag NW conductive interconnects.Due to its excellent performance in sensitivity and strain range,it can be used in the field of real-time monitoring of human physiological health signals and detection of moving limb behavior.更多还原