Preparation And Performance Of Flexible Sensor Based On Graphene Oxide

In recent years,with the development of science and technology,graphene has played a pivotal role in all walks of life due to its excellent physical properties,especially with extremely high current-carrying electron mobility and huge specific surface area,it is the best choice for the preparation of flexible sensor materials.In this paper,by modifying graphene oxide,for the first time,an amino-terminated hyperbranched polymer was used to quickly and conveniently generate nano-silver particles on the surface of graphene oxide to improve the electrical conductivity of graphene oxide.At the same time,ascorbic acid is used for the secondary reduction of graphene oxide to prepare a three-dimensional structure of reduced graphene oxide network,which improves its electrical conductivity.Finally,two flexible strain sensors were prepared by using the prepared graphene oxide-based conductive material,and their sensing performance was studied.First,graphene oxide was prepared by the Hummers method,and then the graphene oxide was modified by epichlorohydrin,and the amino-terminated hyperbranched polymer was successfully grafted on the graphene oxide,and the graphene oxide nano-silver composite was successfully prepared,nano-silver particle size is about 20nm,and good adhesion.Secondly,double-crosslinked hydrogels with excellent mechanical properties were prepared by the hydrogen bonding between the polyvinyl alcohol macromolecular chains and the sodium alginate macromolecular chains.And using the hydrogel as the flexible substrate material and the graphene oxide nano-silver composite material as the conductive medium,a conductive hydrogel,namely a flexible stretch tension sensor,was successfully prepared.The performance of the sensor was tested,and with the increase of strain stretching,it showed good electro-mechanical properties,good sensitivity and cycle stability,and could be applied to the detection of human finger joints.Finally,through the self-adsorption of graphene oxide when ascorbic acid reduces graphene oxide,graphene oxide is reduced in solution and attached to the interior of the polyurethane sponge to form a three-dimensional structure of reduced graphene oxide network,and the rGO/PU conductive sponge is fabricated,namely a flexible strain-compression sensor.The results show that under the same sponge volume,when the amount of loaded reduced graphene oxide is 9 mg,the sensitivity is the highest,which is 12.42 kPa-1(0-5 kPa).And it has a very fast response.Under different pressures of 0-10 kPa,its reaction time does not exceed 1.1 s;during the cycle,it shows good compression repetition stability.As a sensor,motion indicators can be detected through pressure and compression,which has great application potential.