Research On Fabrication Of Flexible Electrode Based On Patterned Microgroove Surface

Electrodes are an important part of electronic devices.Preparing flexible electrodes with excellent performance in a simple way is a research hotspot and has achieved a lot of results.However,there are still many limitations in the current research.In order to easily prepare flexible electrodes with excellent performance,patterned microstructures were introduced on pre-cured viscoelastic substrates by inkjet printing.Flexible micro-structure electrodes were obtained by subsequent plasma treatment of the micro-structure surface,deposition of active conductive material or steaming of metal.Due to the gain effect of the electrodes and surface microstructures,they could be used in fields such as supercapacitors and sensors.?1?Research on the preparation of microstructures by inkjet printingPatterned microstructures were prepared using pre-cured polydimethylsiloxane?PDMS?as the printing substrate and polyacrylic acid?PAA?as sacrificial ink by inkjet printing on PDMS.By quantitatively controlling the pre-curing time of the viscoelastic PDMS surface,the concentration of PAA sacrificial ink and the number of printing layers,the effects of these factors on the specific morphology of the printed microstructures were discussed in detail.The results showed that when the pre-curing temperature was 70?,the pre-curing time was 14 min,the gel rate was 47.35%,the concentration of PAA sacrificial ink was 14%,and the number of print layers was 4layers,the line structure prepared by inkjet printing had obvious morphology,its width was 8.0±0.5?m,and its depth was 4.0±0.5?m.?2?Preparation of microstructure electrode and its application in flexible strain sensorsThe PDMS microstructural surface prepared by inkjet printing was treated,and the flexible microstructural electrodes with high conductivity were prepared by ion sputtering on the PDMS surface.Small bulbs could be illuminated with micro-structured/non micro-structured flexible electrodes when they were not subjected to compression.However,only the micro-structured flexible electrodes could still light up the small bulbs after a certain compression distance ratio.The performance of the micro-structured flexible electrodes was tested.The results showed that the micro-structured flexible electrodes had better flexibility than those without microstructures.For flexible electrodes with point structure,the maximum compression distance ratio could be up to 40%without loss of conductivity.For flexible electrodes with linear structures,due to the anisotropy of linear structures,the flexibility performance of the electrodes varies greatly when the applied compressive forces were parallel and perpendicular to the linear structures,respectively.When the applied compression force was perpendicular to the line structure,it could only withstand a compression distance ratio of 7%,even less than the strain that a flexible electrode without micro-structured could withstand.When the applied compression force was parallel to the line structure,the maximum compression distance could be sustained up to 78%and the normal conductive performance could be maintained.For flexible electrodes with cross-microstructures,it had the largest compression distance ratio and maintains good conductivity when the compression distance ratio was 90%.In addition,several bending tests also showed good stability.In subsequent experiments with finger joints monitored by this method,the current of each bending angle will change correspondingly.?3?Preparation of micro-structured electrodes and its application in supercapacitorsThe micro-structured PDMS surface prepared by inkjet printing was treated to facilitate the further deposition of active materials on its surface.Microstructure surfaces were treated with surfactant sodium dodecylbenzenesulfonate?SDBS?and plasma treatment,respectively.The results showed that the contact angle between PDMS surface and solution was smaller after plasma treatment,which improved the spread and deposition of graphene oxide/silver nitrate?GO/Ag NO₃?solution on the surface of microstructures.Micro-structured electrodes with reduced graphene oxide/silver?r GO/Ag?were prepared from hydrazine hydrate vapor phase.The electrochemical performance of r GO/Ag electrodes was tested.The cyclic voltammetric results showed that the flexible electrodes with micro-structured increased their specific capacitance due to the introduction of microstructure compared with the flexible electrodes without microstructure prepared under the same conditions.At a scanning rate of 0.05 v/s,the maximum area specific capacitance could reach 62.1 m F/cm².At different scanning rates,the micro-structured flexible electrodes showed good electrochemical stability,and constant current charge-discharge tests showed that the electrodes had good stability.