Preparation And Properties Of Bionic Micro-structured Graphene High Elastic Strain-insensitive Conductive Fiber

With the rapid development of flexible electronic devices,flexible intelligent wearable devices have gradually appeared in people's daily life,and conductive fiber has become the focus of research in the field of intelligent wearable.At present,the most widely used conductive fiber in intelligent wearable is the metal conductor.Although the metal conductor has excellent conductivity,but is limited by its high quality,non-stretchability and poor comfort.The elastic conductive fiber has been reported can achieve a large range of stretching deformation,the conductive property of the conductive fiber declines sharply with the increase of the stretching ratio,which affects the stable signal transmission.To satisfy both high elastic and conductive stability of conductive fiber,inspired by nature worms crawling,this paper adopts prestressed were prepared worm structure graphene conductive fiber,and its mechanical properties,electrical conductivity and durability,abrasion resistance and special strain-insensitive properties was tested.The main research contents are as follows:?1?In order to prepare graphene with large quantity and high quality in the lab,graphene with few or even single sheets was prepared by high pressure homogenization method,and the graphene has a large transverse size?average 5?10m?.The graphene edge was counted by TEM,and it can be seen that the graphene with single sheets is easy to operate,low cost,and environmentally friendly.?2?In order to prepare the strain-insensitive graphene conductive fibers,the film construction method was used to screen the ratio of graphene and polyurethane mixed conductive coating,and the coating showed good film formation and conductivity when the graphene solid content was 30%.Taking polyurethane elastic fiber as elastic matrix,and graphene and polyurethane conductive coating as conductive material,graphene conductive fiber with different pretension ratio was prepared by prestressing method.?3?In order to select the optimal strain insensitivity of graphene conductive fiber,the preparation of different pre-draft ratio graphene conductive fiber on the performance test.The as-prepared graphene conductive fiber has high elongation at break?over 1010%?and low modulus fracture strength?about 30 MPa?.The graphene conductive fiber with 300%has a very wide reversible electrical response range?0<?<815%?,good initial resistance?2079??,excellent durability?more than 4000 times tensile-release cycles of 10%strain ratios?and good wear resistance.The most important is that GP₃₀₀@filament conductive fiber has excellent strain insensitive properties,which strain-insensitive range??R/R₀<0.1?at 220%strain.And in 300%strain ratios,The strain-insensitivity coefficient of the GP₃₀₀@filament conductive fiber is up to 11.26,which is higher than most elastic conductor materials have been reported.?4?In order to highlight the strain insensitivity of the conductive graphene/polyurethane fiber with 300%pre-tensile ratio,and to simulate the actual use of the conductive fiber.In this paper,GP₀@filament and GP₃₀₀@filament conductive fibers are designed as contrast application experiment by respectively use as the wires of simple weighing balance and LED lamp.By stretching the two wires to the same degree,the resistance of the GP0@filament changes significantly,while the resistance change of the GP300@filament could be almost ignored,which can dramatically highlight the excellent strain-insensitive performance of GP₃₀₀@filament conductive fiber.To test the actual wearable application of GP₃₀₀@filament conductive fiber for its strain-insensitivity,it was connected to the LED lamp and woven into the fabric.Simulated the complex deformation of the fabric such as stretching,kneading,twisting,rolling and the large deformation caused by the human joint movement.The brightness of the LED did not change during the whole process,and the change in the total resistance of the circuit was negligible.