The Investigation Of Three-dimensional Direct Writing To Print Flexible Stretchable Electronics

With the development of technical,the traditional electronics due to its high energy consumption,low deformation and other disadvantages,has been unable to meet the higher requirements for new electronic product.As a result,with low energy consumption,high deformation of the flexible stretchable electronics has attracted a large amount of attention due to its properties in stretchable,foldable,twistable and other deformation performance in scientific research field.As a novel technology,three dimensional direct writing can fabricate customized patterns or structures without any moulds,laser or ultraviolet light at room temperature,which subverts the traditional template method of manufacturing,making the manufacturing process more simple and quick.Combining the advantages of the conductive ink and the elastomer,through applying the conductive ink and elastomer as the core and shell materials,respectively,a coaxial printing method is being developed in this work for preparing a stretchable(?=150%)and conductive cable.While the conductive ink must own the properties of high conductivity and low melting point,in addition,the elastomer have to meet the demand of high viscosity,high strain and easy cure.Finaly,the conductive cable exhibits a good conductive performance when it is in high strain state.The cable will be widely applied in wearable devices,soft robots fields in the near future.The main contents and conclusions of this paper are summarized as follows:1.According to many literature materials and analysis on the research achievements,this paper has mainly concentrated on the investigation of the liquid metal alloy eutectic Gallium-Indium(EGaIn)-polydimethylsiloxane(PDMS)cable and the carbon conductive grease-polydimethylsiloxane(PDMS)cable.We report a coaxial writing process for rapidly prototyping a stretchable and conductive cable by the means of direct writing with a coaxial nozzle.This paper systematically studied how to prepare and package the conductive cable,and the key parameters for improvement of the preparation method were also investigation to produce a high quality stretchable cable.2.What is more,the resistance tests in different conditions were carried out for the stretchable conductive cable prepared by 3D method,including the fitting test of the resistance and strain,the relationship of resistance and strain in repeatability cycling tests,the impact of temperature on the resistance,the impact of pressure on the resistance,and so on.Through the results of comparison,the overall performance of liquid metal cable is much better than the performance of carbon conductive grease cable.3.Owning to the high conductivity performance of EGa In-PDMS cable,it was applied for high strain in different fields for potential application.As the wire,when it was connected with a light emitting diode(LED)in simple circuit,it can maintain lighting without attenuation of brightness when it was stretched and in the initial state,which proves it was indeed a good performance wire.As an intelligent protractor,when it was stretched along the central axis of the vertical,it can reflect the stretchable angle.As the strain sensor,it was mounted in the body joint parts to capture movements of an object such as human's elbow or leg joint including both frequency and amplitude.These extended applications show that the stretchable cable has a huge potential prospect of achieving widespread application.