Application Research Of Ion Conductive Hydrogel In Flexible Display And Sensor Devices

The advantages of smart wearable flexible devices and equipment in medical,healthcare,sports and beauty applications are emerging year by year.Among the many functional materials constituting flexible devices,hydrogel conductive materials have been widely used in smart wearable flexible devices because of their excellent flexibility,stretchability and biocompatibility,etc.Recently,a series of capacitive-resistive,electrodes,and others forms of hydrogel devices have been produced,resulting in a leap forward in the development of devices and equipment based on hydrogel materials.However,the wide range of uses and diverse application environments of flexible devices impose various specific requirements on the basic characteristics of hydrogel materials and flexible devices,such as the need for ionic conductor conductivity and flexibility in low-temperature environments;the need for biocompatibility and stable energy supply in the human body environment,etc.Only the development of hydrogel-flexible devices based on different functions for different application environments can really lead the basic research in this field to applications.In this paper,the application of flexible hydrogel devices in biological scenarios was studied,achieving a low-temperature flexible automatic display,a pressure sensor that can simulate skin touch and generates nerve ion signals,and a flexible optoelectronic sensor that simulates the eye.These findings provide strong support for the further development of intelligent wearable and implantable devices.The major research of this study is summarized as follows:1.This study aims to address the issues of low conductive and loss in flexibility of flexible display devices at low temperatures.To achieve this,the study utilized nanoparticles based on antifreeze propylene glycol and high dielectric constant as the substrate material for the flexible display.The study successfully prepared and controlled a flexible and stretchable display device that can automatically display at low temperatures.Additionally,the study combined a high-voltage-driven flexible display interface with a low-voltage-driven electronic circuit,solving the voltage mismatch problem during the experimental process and achieving automatic control of the flexible display device at low temperatures.2.This study addresses the problem of incompatibility between hardware circuits and the biological neural networks and the problem of dependence on external power supply.by designing a selfpowered mechanical pressure sensor for pressure detection.The sensor is composed of a hydrogel ion diode made of anionic and cationic polymers.Under mechanical pressure,the sensor generates alternating current or voltage signals similar to action potentials of synapses,which can be connected to biological to achieve information transmission and processing between the biological body and the external environment.The study constructs a PN junction hydrogel elastic network by cross-linking polar ion monomers.One type of ion is fixed on the chain to form a network,while the other type of ion can move freely,building a PN junction hydrogel with directly combining polyanionic hydrogel and polycationic hydrogel.The study used polyelectrolyte hydrogels to prepare the flexible device,avoiding the need for conductive hydrogels doped with ionic liquids,MXene,carbon nanotubes,and other conductive fillers,thus meeting the requirements of material biocompatibility for wearable devices.3.This study designs a flexible self-powered optoelectronic sensor device that simulates the perception of light sources by the human eye.The sensor uses a biocompatible PN junction hydrogel and adds 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt(HPTS)photoacid solution into the side where cations form a network through a drying and quantitative swelling process,producing a green fluorescent light-responsive polycationic hydrogel.An electric field is generated at the interface of the polyanionic and polycationic gels,and static adhesion occurs between the two elastomers,forming a hydrogel-based ion diode.When the polycationic hydrogel is illuminated,the HPTS photoacid molecules inside the hydrogel lose protons under light excitation,and then recombine protons in the dark,changing the voltage on both sides of the hydrogel diode,producing a membrane potential difference similar to the photoreceptor cells in the eye.The study used water as the sole solvent in the preparation process and as the carrier for ion migration,avoiding harmful solvent residues that can cause harm to the human body.The application part borrows the electronic circuit upper computer interface to test the light-sensitive changes of the array model,and successfully demonstrates the process of artificial retina to simulate light-sensitivity and generate electrical signals.