Fabrication And Performance Study Of Two-Dimensional Transition Metal Flexible Sensor

With the progress of the times and society,there is an increasing demand for the development of high-performance flexible sensor devices.Especially in applications such as personalized health monitoring,human motion detection,human-machine interface interaction,and flexible bionic robots,corresponding flexible pressure/strain sensor components are required as the basis for device support.However,flexible pressure sensors still face a great challenge to combine fast frequency response,wide pressure range,multiple detection modes,satisfactory mechanical and environmental stability,and simple fabrication process into a sensor.To solve these problems,we have chosen a new two-dimensional sheet-like transition metal carbonitride with high conductivity as a conductive material for constructing a flexible sensor device in combination with a flexible polymer material,through a simple vacuum impregnation method,we can produce flexible sensors that can be used in a variety of situations.The contents of this subject are as the following parts:(1)Two-dimensional flake Ti3C2Tx MXene was successfully prepared by etching the MAX phase precursor with hydrochloric acid/lithium fluoride:It is difficult to prepare a single layer of MXene.In this experiment,we etched the MAX phase precursor by in situ formation of hydrofluoric acid by hydrochloric acid and lithium fluoride,which reduces the risk of direct use of hydrofluoric acid.The coefficient,on the other hand,lithium ions can act as an intercalation.By accurately controlling the etching temperature and time,we prepared a monolithic MXene aqueous dispersion with satisfactory conductivity;(2)Preparation of MXene coated polyurethane composite foam,and explore its sensing properties:The preparation of output stabilization signals and the use of reliable polymer-based flexible sensors have led to a major focus of current research.In this experiment,chitosan with positive potential and MXene with negative potential were alternately coated on commercial polyurethane foam by means of electrostatic self-assembly with mutual attraction of positive and negative charges,and a flexible strain sensor with high reliability,stability and sensitivity was assembled.When the polyurethane foam was vacuum-impregnated in MXene water dispersion for two times,its gauge factor could reach 3.0,response time was 19 ms,the minimum detection limit was 3 mg,and various forms of movement could be monitored in contact mode and non-contact mode.(3)Preparation of flexible porous PDMS foam and coated with MXene sheet to prepare wearable sensors with satisfactory flexibility:In this experiment,we prepared PDMS foam by vacuum impregnation using a food grade candy block as a template.On the one hand,chitosan can improve the hydrophobicity of PDMS foam.On the other hand,MXene can be tightly coated on the framework of PDMS foam to form a perfect conductive path for the preparation of flexible sensor parts.MXene coated PDMS foam was thinly cut and assembled to form a flexible sensor,it was tested at the same bending frequency,different bending angles and the same bending angle at different bending frequencies,and all of them could make good feedback.When applied to different parts of the human body,it can provide timely and effective feedback on human behavior,the response time in human body application is only about 50 ms.