Experiment And Simulation Of Tunnel Encapsulation Technology Of Stretchable Electronics

With the advent of the era of digitization and intelligent,human–machine interaction is becoming a major challenge in the fields of electronics,machinery,and medical treatment.Flexible and stretchable electronic capture the attention of industry and academia in order to meet the demands of portability,flexibility and applicability for the next generation of electronics products.Along with the rapid development of stretchable electronics,a variety of processing techniques and materials have been used in the fabrication of stretchable electronic devices.The technology of direct encapsulation(encapsulating a serpentine metal electrode with Polydimethylsiloxane)is widely used because of its advantages such as ease of operation and low cost.However,metal electrodes with direct encapsulation may cause stress concentration due to restraint of the silicone polymer and thus have poor durability.In this paper,tunnel encapsulation technology is proposed to reduce the stress of the metal electrode during stretching and increase the stretchability and durability of the ductile electronic device.The technology forms a sandwich structure of polyvinyl alcohol film/metal electrode/polyvinyl alcohol film at first,and then encapsulates the structure with a silicone polymer,and finally dissolves the polyvinyl alcohol which is coated on the metal electrode to form a micro-tunnel which surround the metal electrode.Due to the existence of the micro-channel,the metal electrode can be twisted and slipped in the tunnel when the device is stretched,which greatly reduces the stress.Experiment results have shown that the sample can be stretched repeatedly for 20,000 times at 50% elongation while it can still work stably.In our demonstration,a stretcheble LED device was designed and fabricated with tunnel encapsulation,and its performance was tested to verify the practicability of our technology.The tunnel encapsulation technology proposed in this paper enables stretchable electronic device to adapt to various complicated and harsh environments and stabilize the operation,which helps to promote the development and application of stretchable electronics.