Research On Flexible Strain Sensor And Flexible Actuator Based On Laser-induced Graphene Technology

In recent years,as one of the research hotspots in the field of electromechanics,flexible electronic devices have received extensive attention.Flexible electronic devices have the characteristics of small weight,low stiffness and strong deformation ability,and the application range of flexible electronic devices is more flexible than traditional electronic devices.Laser-induced graphene(LIG)technology is a commonly used technology for preparing electrode materials for flexible electronic devices,which prepares graphene-containing two-dimensional electrode materials by burning polyimide(PI)surface,and has the characteristics of low cost,fast rate and mature process.Scholars have used LIG technology to develop many flexible electronic devices with good performance,among which LIG electrodes have great potential in the application of flexible strain sensors and flexible actuators.However,in terms of flexible strain sensors,most of the flexible strain sensors based on LIG electrodes have not formed a stable and repeatable processing process,and the consistency of structural dimensions and sensing performance between the same type of strain sensors is poor.In terms of flexible actuators,there is less research on the use of LIG electrode technology with more convenient preparation methods for flexible electrodes,which is usually composed of materials such as silver paste,carbon black,and carbon nanotubes with higher cost and cumbersome processing.In order to solve the above problems,this study will explore the method of synergistic preparation of LIG flexible strain film sensors and LIG flexible thin film actuators with good performance.First,this paper designs the flexible electrode and its manufacturing process.Poly-dimethylsiloxane(PDMS)converted from liquid to solid forms a soft film that adsorbs the PI-LIG joint layer;Then the PI is corroded with strong alkali and the LIG-PDMS flexible electrode is separated without injury.The LIG-PDMS flexible electrodes produced by this process are the core of flexible strain sensors and actuators.Secondly,this paper designs a LIG flexible strain thin film sensor with high consistency in structural size and sensing performance,and designs a stable and repeatable processing process for the sensor.According to the test of the obtained LIG flexible strain thin film transducer,the structural dimension of the thin film sensor is accurate,and the error is±0.06 mm.After the LIG is packaged,the microstructure inside the silicone of the thin-film sensor is uniform;When the thin film sensor is subjected to normal extrusion stress,the linear change range is 28.36%,the sensitivity coefficient is 28%,and the resistance repeatability of the thin film sensor is good when subjected to periodic normal extrusion.When the thin film sensor is subjected to axial tensile stress,its linear change range is 25.02%,the sensitivity coefficient is 37%,and the resistance repeatability of the thin film sensor is good when subjected to periodic axial tension.Finally,a LIG-PDMS flexible electrode is used to build a LIG flexible dielectric elastomer actuator with a double-layer electrode,a thin dielectric layer(0.149 mm)and a deformation response time of as low as 0.04 s.It is also verified that the soft robot built by this actuator has a crawling speed of 0.44 mm/s.In this paper,flexible strain sensors with good electrical sensing performance and high consistency and flexible actuators with fast response were co-prepared based on LIG technology.The specific application scheme of these two flexible electrodes provides inspiration for the application of LIG in the direction of flexible electronic devices.