| Owing to their unique properties such as great stretchability and light weight,flexible electronics have attracted intensive attention in recent years.Room-temperature liquid alloy is easy for use and has high conductivity,which is suitable for flexible electronics.Liquid alloy direct writing for flexible electronics shows attractive features,such as convenience and customized prototyping capability,but the resolution is limited by the size of nozzle.An important trend is to fabricate complex circuits with varied sizes in a small area rapidly and precisely,thus it is important to improve the resolution when using convenient direct writing.This thesis improves liquid alloy direct writing and presents a new method based on viscoelastic flow squeezing.Viscoelastic flow is introduced as outer flow in coaxial nozzle and inner flow liquid alloy will be wrapped at the outlet of the inner nozzle.Because of flow focusing and extruded swelling,liquid alloy is squeezed by viscoelastic flow and then the resolution will be improved when printing.After studying the feasibility of coaxial printing via changing the behavior of liquid alloy in coaxial nozzle,the influence mechanism of relevant parameters on trace width was studied to tune the resolution of printed liquid alloy trace in real time through adjusting the value of relevant parameters.The width of liquid alloy was 81 ?m before parameters adjusting and decreased to 45 ?m after the adjusting.Tensile testing showed the stability and sensibility of the device fabricated using the technology demonstrated above.Finally,two flexibly selective heating devices were designed and can be used to heat the different sections selectively.In summary,fast and precise processing can be achieved and the resolution can be tuned in real time as needed via the new technology for complex liquid alloy patterning presented in this thesis,which is important for miniaturization and industrialization of soft electronics. |
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