Electrospun green fluorescent-highly anisotropic conductive Janus-type nanoribbon hydrogel array film for multiple stimulus response sensors

Abstract

A new strategy aimed at significantly enhancing the anisotropic conductivity of hydrogel materials, along with a simple construction technology and design concept, are proposed. Anisotropic conductive hydrogel materials have attracted much attention from researchers in the field of flexible electronics for their inherent excellent properties. However, the anisotropic conductivity of the existing conductive hydrogels is not high and the preparation methods are complex. Herein, fluorescent-highly conductive anisotropic Janus-type nanoribbon hydrogel array film (named JNHAF) is successfully prepared using a combination of parallel electrospinning and post-polymerization as an example of the study. Highly oriented [2,7-dibromo-9-fluorenone (DF)/gelatin (GE)]//[carbon black (CB)/GE] Janus-type nanoribbon is used as the building block. The composition as well as the arrangement of Janus-type nanoribbons are microscopically designed and regulated to effectively separate the conductive and insulating materials, so that the samples can achieve highly anisotropic conductivity and obvious green fluorescence. When the mass ratio of GE to CB is 1:0.1, the conductive anisotropy ratio of JNHAF can reach 1.12 × 10⁵. The degree of anisotropic conductivity of JNHAF is significantly improved compared with existing reported anisotropic conductive hydrogels, and the preparation method is simple. JNHAF responds quickly to light, tensile strain, and temperature, making it suitable for assembling multi-stimulus responsive sensors. JNHAF has excellent flexibility, degradability, mechanical properties and a certain degree of sensitivity (gauge factor of 4.29), and is used for human joint motion detection with an obvious response signal. The design idea and construction technology of this hydrogel breaks through the technical bottleneck of the low degree of anisotropy of conductive hydrogels, which will lead and expand the scientific frontiers of anisotropic conductive hydrogel materials, and provide novel design ideas and theoretical values for new hydrogel materials.