【作者】 王琳；

【导师】 张美云； 杨斌；

【作者基本信息】 陕西科技大学 ， 轻工技术与工程， 2022， 硕士

【摘要】 柔性压力传感材料因其高柔性、高灵敏等优势,广泛应用在电子皮肤、人体智能监测以及植入式医疗设备等领域,实现了智能化、便捷化及科学化的健康生活。随着社会发展,实现兼具高灵敏度、宽检测范围和快速响应的柔性压力传感材料成为当前的研究热点及挑战。目前,纤维基传感材料的种类较少且材料的结构和性能之间不可控;膜类材料传感性能不突出,且应用领域单一;三维气凝胶基传感材料制备复杂、成本高且材料的结构易塌陷。因此,本文选用芳纶纳米纤维(ANFs)复合高导电MXene,构筑出多维度的柔性压力传感材料,应对不同维度的传感材料所面临的性能与结构之间的挑战,并以各自的性能优势实现了在多领域的应用。具体结果如下:采用湿纺丝工艺制备具有皮芯结构的1D MXene@ANFs纤维传感材料。高强、高模的ANFs作为纤维的皮层及骨架结构,赋予了纤维以高强度达130 MPa;MXene作为功能材料赋予纤维高导电性(2515 S·m-1)。通过调控纺丝工艺,实现结构可控的智能纤维的连续化制备。MXene的焦耳热效应使MXene@ANFs纤维还呈现出优异的电热性能,短时间(10 s)内实现宽加热温度(25-123℃)。将MXene@2%ANFs智能纤维缝制到纺织品和手套中,可作为智能织物传感材料成功检测人体各项肢体运动,其响应时间缩短至100 ms,循环使用寿命高达1000次。优异的传感性能和高柔韧性使纤维传感材料在智能可穿戴领域表现出极大潜能。采用真空抽滤辅助冷冻干燥制备ANFs/MXene气凝胶膜传感材料。在定向力的作用下,ANFs与MXene相互缠绕包裹,并借助冰晶生长构筑出具有定向、多层级网络结构的气凝胶膜。对气凝胶膜表面抗水处理后,接触角高达158℃,优异的疏水性为水下传感研究提供了技术依据。ANFs/MXene气凝胶膜传感材料的耐折度高达6000余次。相比于结构致密的薄膜,气凝胶膜内部多孔结构使其在感知刺激时表现出更高的灵敏度,可成功检测人体指节弯曲、握拳、说话、眨眼、微笑等一系列肢体动作和微表情。通过可控真空过滤和冷冻干燥等工艺,成功制备出具有高压缩性、优异隔热性能和高灵敏度的3D MXene/ANFs气凝胶,其中ANFs充当复合气凝胶材料的骨架结构和抗氧化保护层,用来弥补MXene脆性大、抗压性弱、回弹性差且易氧化等缺陷。MXene构筑复合气凝胶内部连续的导电通路,其占比为30%时,气凝胶的孔结构达到最佳,此时气凝胶的力学性能和导电性达到平衡。作为一种压阻传感材料,MXene/ANFs气凝胶传感材料实现了宽应变范围(2-80%),宽压力范围(0.1-623 kPa)的成功检测,响应时间为320 ms、恢复时间98 ms,其灵敏度可高达128 kPa-1。将MXene/ANFs气凝胶传感材料用作智能鞋垫可检测人体跳绳、行走甚至奔跑等运动。本研究构筑1D功能化纤维传感材料,以高柔性可组装为智能织物;2D气凝胶膜传感材料以更宽的响应范围,实现对人体肢体运动的全方位监测;具有结构-性能优势的3D气凝胶传感材料,以突出的压缩回弹性实现超高的灵敏度。制备得到的不同传感器实现了功能上递进又满足了功能上互补,在人体健康监测和临床医疗监测设备等领域显示出极大的应用前景。丰富了现有传感材料的种类的同时实现了材料的高价值利用,符合可持续发展的经济方针。更多还原

【Abstract】 Flexible stress sensor with high flexibility and sensitivity has been widely used in electronic skin,intelligent monitoring of human body,implantable medical equipment,realizing intelligent,convenient and scientific technological progress.With the social development,the realization of flexible pressure sensing materials with high sensitivity,wide detection range and fast response has become the current research hotspot and challenge.Therefore,Aramid nanofiber(ANFs)composite with highly conductive MXene were used in this study to construct multi-dimensional flexible pressure sensing materials,which solves the problem of cumbersome and poor sensing performance of traditional sensing materials and meets the needs of different fields with multi-functional performance advantages.The specific results are as follows:1D MXene@ANFs fiber with skin-core structure was prepared by wet spinning process.ANFs with high strength can be used as skeleton structure,the mechanical strength of fiber can up to 130 MPa,while MXene as a functional material gives the composite fibers high conductivity(2515 S·m-1).By adjusting the parameters of the wet process,fibers with diversified structures were realized.Due to the unique Joule heating effect of MXene,MXene@ANFs fiber also has excellent electrothermal properties,achieving wide heating temperature(25123℃)at a short time(10 s).The MXene@2%ANFs fiber could be sewn into textiles and gloves as smart fabric sensing material,with fast response time and long cycle life.The fiber with outstanding sensing capability and high flexibility shows potential in constructing intelligent wearable sensing devices.2D ANFs/MXene aerogel film sensing material was prepared by vacuum filtration and freeze drying.Under the action of directional suction force,ANFs and MXene wrapped each other,and the aerogel film with orientation and multilayer network structure was constructed by ice crystal growth.The contact angle of aerogel film is as high as 158° after surface water resistance treatment,which provides technical support for underwater sensing research.The ANFs/MXene aerogel film sensing material has a folding resistance of more than 6000 times,showing extremely high flexibility and mechanical properties.Compared with the tight structure,aerogel film shows higher sensitivity due to its porous structure,it can be used as a highly flexible pressure sensor to successfully detect a series of body movements and micro-expressions such as knuckle bending,clenching,speaking,blinking and smiling.MXene/ANFs aerogel with high compressibility,excellent heat insulation and high sensitivity was successfully prepared by controllable vacuum filtration and freeze drying.ANFs acts as the skeleton structure and antioxidant protection layer to compensate for the defects of MXene,such as brittleness,weak compressive resistance,poor resilience and easy oxidation.MXene plays a role in excellent conductive pathway.Ultimately,30%MXene/ANFs aerogel realizes great pore structure,along with the balance between mechanical properties and electrical conductivity.As a piezoresistive sensing material,MXene/ANFs aerogel sensing material achieves successful detection of wide strain range(280%),wide pressure range(0.1-623 kPa),the response time is 320 ms and the recovery time is 98 ms.MXene/ANFs aerogel sensing material can be used as intelligent insole to detect human jumping rope,walking and even running,and its sensitivity is up to 128 kPa-1,showing great application prospects in human health monitoring and further clinical monitoring equipment.In this study,1D functional fiber sensing material was constructed,which can be assembled into smart fabric with high flexibility.2D aerogel film sensing material can realize the all-round monitoring of human limb movement with wide sensing range.3D aerogel sensing materials with structure-performance advantages achieve super sensitivity with outstanding compression resilience.The different sensors have achieved progressive function and complementary function,showing great application prospect in human health monitoring and clinical medical monitoring equipment.It enriches the variety of sensor and realizes the high-value utilization of materials,which is in line with the economic policy of sustainable development更多还原