Flexible Electronic Device Based On Hydrogel

In recent years,wearable technology has developed rapidly and has entered practical applications,such as flexible displays,Huawei smart glasses,etc.Although these have entered people's lives,the key parts of flexible electronic devices that have entered applications are still using rigid ones,such as batteries and chips.These can't be bent.Therefore,it is not yet possible to achieve full flexibility.There is still a long way for fully flexible electronic devices to enter daily life,and there are still many problems need to be solved.Among the many problems,the first one is the battery problem.Traditional lithium batteries/capacitors are rigid and difficult to meet the requirements of flexibility.For this reason,researchers can actively explore ways to solve this problem.Using a triboelectric nanogenerator(TENG)to convert the collected low-frequency mechanical energy from human motion into electrical energy is one of the many ways to solve this problem.This article focuses on multifunctional sensors and energy devices based on hydrogel.A dual-network super-stretchable antifreeze hydrogel sensor is prepared,which realizes multifunctional sensing.A new transparent hydrogel-based energy device has been developed to achieve stable output in harsh and complex environments and to supply power to electronic watches.The main results of this paper are as follows:1.A multifunctional sensor is designed.It can simultaneously realize stress and strain sensing,self-powered identification of materials,and identification of object weights and positions.The dual network of polyvinylpyrrolidone(PVP)and polyacrylamide(PAM)is introduced into the hydrogel,so that our hydrogel has super stretchability(?=90),which is much higher than t stretchable devices based on carbon material-ITO,Ag wire and other electrode materials.Similarly,water is introduced as a dispersion medium,and Na Cl is added to make the hydrogel conductive;ethylene glycol(EG)is added to reduce the freezing point of water,so that the hydrogel has frost resistance.The hydrogel is prepared into a multifunctional sensor,which realizes pressure sensing,strain sensing,identification of different flat materials and identification of the position of the object and the corresponding weight,and the sensor also has self-powered characteristics.And the multifunctional sensor can have stable cycle performance(600 cycles)under the condition of large strain(100%—600%).The sensor can also detect changes in human physiological signals,such as finger bending,not only that,but also the angle of finger bending.2.An energy device is designed,which can maintain high and stable output performance in strong acid,strong alkali,saline alkali,and marine environments.A hydrogel based on polyacrylamide(PAM)is prepared,and these PAM chains are physically and covalently cross-linked with each other to form a network.During this process,the added ?-CD penetrates into the already formed PAM chain to form a polypseudorotaxane structure.These polypseudorotaxane chains are cross-linked with each other and form Cyc-hydrogel.Due to the introduction of ?-CD,the hydrogel has excellent environmental stability.This makes CycTENG made of Cyc-hydrogel also has super environmental stability.When used as an electrode of TENG,it was found that the output performance of TENG was almost unaffected,thereby maintaining high output performance and good stability.Therefore,Cyc-TENG has huge application potential when collecting blue energy.Not only that,Cyc-TENG can also power flexible devices.CycTENG replaces traditional batteries,powers electronic watches,and can also light up commercial LEDs.It can also power electronic watches in harsh environments.It can be seen that Cyc-hydrogel as the electrode material of TENGs provides great application potential for blue energy and flexible electronic device energy equipment.