Photoresponsive multifunctional anisotropic conductive hydrogel membrane for human motion detection, information encryption and transmission

Abstract

A new strategy is proposed to construct highly anisotropic conductive hydrogel materials. As a case study, a highly oriented [cobalt ferrite (CoFe₂O₄)/gelatin (GE)]//[2,7-dibromo-9-fluorenone (DF)/GE] Janus nanobelt is fabricated using parallel electrospinning and polymerization methods, and used as building blocks to construct a photoresponsive luminescent-conductive-magnetic triple function Janus nanobelt hydrogel array membrane (JNHAM). Under light irradiation, JNHAM exhibits anisotropic electrical conductivity, distinctive green luminescence and magnetic properties. When the mass ratio of GE to DF is 1 : 0.2, the degree of anisotropic conductivity of JNHAM is up to 115. In the absence of light irradiation, JNHAM only exhibits magnetic properties. The conversion of the non-anisotropic conductivity to anisotropic conductivity in JNHAM is achieved by utilizing the presence or absence of light. JNHAM responds rapidly to changes in light, temperature, and tensile strain, making it suitable for constructing multi-stimulus-responsive sensors. Changing the presence or absence of light, temperature, load and stress can alter the sensor function and the strength of electrical signals. This sensor can be used for information encryption and transmission. The magnetism of JNHAM can reach 24.68 emu g⁻¹, so it has certain applications in magnetic drive and magnetic anti-counterfeiting fields. JNHAM exhibits significant green luminescence at 522 nm, enabling the visualization study of materials. The design idea and construction technology of this hydrogel solved the technical bottleneck of the complex and difficult construction method of the anisotropic conductive hydrogel. The use of simple materials endows the hydrogel materials with versatility, expands the application range of sensors, and advances the scientific frontier in the field of anisotropic conductive hydrogel materials.