Preparation And Research Of Three-dimensional Flexible Strain Sensor

As one of the hot research directions in the field of flexible electronic devices,flexible strain sensor has the characteristics of thin,portable and deformable.It has great application prospects in electronic skin and smart wearable devices.At present,the research of flexible strain sensors mainly focuses on the tensile and bending deformation detection of one-and two-dimensional planes,but fails to realize the expansion deformation detection of 3D devices.However,the existing research of three-dimensional flexible strain sensors mainly used for pressure detection.At present,the main problems in the research of 3D flexible strain include: lack of complete design and preparation technology of 3D flexible strain sensor,and the detection process of 3D flexible strain sensor has not been established.The detection accuracy and performance of 3D structure flexible strain sensor need to be improved.In this paper,the structure design,preparation process,detection method,performance improvement and application of 3D flexible strain sensor will be studied.This paper focuses on the 3D structure deformation detection as the research object,respectively from the preparation of 3D structure sensor materials,three-dimensional structure design and detection applications.Firstly,the resistivity and tensile strain limit of the conductive composites prepared by PDMS/graphene and Ecoflex/graphene materials under different mixing ratios were studied,and Ecoflex/graphene conductive composites with good performance were selected as the materials for the preparation of flexible strain sensors.By designing the flexible strain sensors with solid linear structure,quadrilateral mesh structure and hexagonal mesh structure,and studying the elastic modulus,tensile breaking limit load and sensitivity of the three kinds of flexible strain sensors,the feasibility of Ecoflex/ graphene conductive composites in the preparation of flexible strain sensors was proved.At the same time,the response time,fatigue life analysis,breathing detection and elbow bending detection experiments of the hexagonal mesh flexible strain sensor were carried out,which further proved the feasibility of the3 D flexible strain sensor prepared by Ecoflex/graphene conductive composite material.Secondly,based on the feasibility of producing 3D flexible strain sensor with Ecoflex/graphene conductive composite material,this paper proposes a scheme for fabricating 3D flexible strain sensors with hat structure,cube structure,cylindrical structure,regular tetrahedron structure,and fishing net structure using mold methods.The3 D flexible strain sensor of hat structure and the 3D flexible strain sensor of cube structure were prepared.Based on the structure shape of the hat structure 3D flexible strain sensor,the resistance detection algorithm and application of the hat structure 3D flexible strain sensor are presented.Finally,the digital detection and accurate detection of the hat structure 3D flexible strain sensor are studied.A resistance detection algorithm was proposed for the structure model of 3D flexible strain sensor with hat structure.By analyzing the circuit of the hat structure sensor,the formula for calculating the overall resistance between the two ends of the sensor and the resistance of the six sides of the sensor is deduced.At the same time,under the condition of strain of 0% to 30%,the relationship between the resistance between the two ends of the sensor and the resistance of the six sides of the sensor and the strain was analyzed theoretically and experimentally.The results show that the resistance of the sensor increases gradually with the increase of the strain variable,and it has a good linear relationship.In addition,the linear calibration equations of the resistance change rate and strain on the long and short sides of the sensor were established.Through this calibration equation,the digital detection and accurate detection of kumquat fruit growth and deformation were realized.In addition,the expansion of the 3D flexible strain sensor was studied.Firstly,the preparation and application of the cubic structure 3D flexible strain sensor was completed.The sensitivity characteristics of the sensor under different volume expansion conditions were studied and analyzed.Secondly,the influence of high and low temperature environment on the change of sensor resistance was studied.The results show that the low temperature environment has almost no influence on the change of sensor resistance.With the temperature gradually rising and higher than room temperature,the ambient temperature has a great influence on the sensor resistance.In this paper,a 3D flexible strain sensor with hat structure was prepared based on Ecoflex/graphene conductive composite material,and a digital resistance detection and accurate detection algorithm was proposed for the sensor,which realized the detection and application of the sensor in 3D device deformation.