Compared with traditional rigid electronic devices, flexible electronic devices are flexible, bendable and stretchable, and have wide application prospects in the fields of information, medical treatment, and new energy. The conventional flexible electronic device has a two-dimensional planar structure without external force support. In order to obtain a device with a three-dimensional complex structure, additional supports and fixing measures are often required. Introducing shape memory polymer materials into the field of flexible electronic technology, giving flexible devices active deformation and variable stiffness characteristics, can switch between "soft-hard", from a two-dimensional planar structure to a complex three-dimensional curved surface structure. Flexible electronic devices prepared based on shape memory polymers have reversible shape reconstruction characteristics, which greatly enriches the functionality of flexible electronic devices.
Recently, the deputy chairman of the Chinese Society of Composite Materials and the team of Professor Leng Jinsong of Harbin Institute of Technology successfully designed a flexible electronic device that can be actively deformed based on a transparent shape memory polyimide electrode. The research result was published in the authoritative journal ACS Applied Materials & Interfaces in the field of materials under the title of "Active and Deformable Organic Electronic Devices based on Conductive Shape Memory Polyimide". The first author of the paper is the doctoral student Huang Xinzuo of the research group, and the corresponding author is Professor Leng Jinsong . Related work has received strong support from the National Natural Science Foundation of China.
The team members first prepared a double-layer (Au/Ag) metal grid electrode on the surface of the glass substrate using a self-cracking grid template and a thermal evaporation process, and then transferred it to a transparent shape memory polymer through a solution casting process With an imide substrate, a flexible transparent metal grid electrode embedded on the polymer surface was obtained. The average square resistance value was 5.2Ωsq-1, and the light transmittance at 550nm was 85%. The unique embedded structure makes the electrode have ultra-low surface roughness (Ra ~ 2.7 nm), which meets the stringent surface roughness requirements of OLED and other optoelectronic devices. There is a strong adhesion between the grid electrode and the substrate. Conventional physical damage, such as ultrasonic vibration, is difficult to destroy the integrity of the metal grid. Based on this electrode, an active deformable white light-emitting organic light-emitting diode (WOLED) was prepared. The initial shape of the WOLED device was a two-dimensional planar structure, which depended on the shape memory of the polyimide substrate to change the stiffness characteristics. The temperature was heated to the glass of the substrate When the transition temperature is changed, the WOLED device can be transformed into a complex three-dimensional curved surface structure, which can maintain this stable temporary shape without external force support, and the shape reconstruction characteristics are reversible.