Biomass-Derived,\nHighly Conductive Aqueous Inks for\nSuperior Electromagnetic Interference Shielding, Joule Heating, and\nStrain Sensing

Abstract

Conductive composite inks are widely\nused in various applications\nsuch as flexible electronics. However, grand challenges still remain\nassociated with their relatively low electrical conductivity and require\nheavy use of organic solvents, which may limit their high performance\nin broad applications and cause environmental concerns. Here, we report\na generalized and eco-friendly strategy to fabricate highly conductive\naqueous inks using silver nanowires (AgNWs) and biomass-derived organic\nsalts, including succinic acid–chitosan (SA–chitosan)\nand sebacic acid–chitosan. SA–chitosan/AgNW composite\ncoatings can be prepared by directly casting conductive aqueous inks\non various substrates, followed by subsequently heating for cross-linking.\nThe composite coatings exhibit an ultrahigh electrical conductivity\nup to 1.4 × 10⁴ S/cm, which are stable after being\ntreated with various organic solvents and/or kept at a high temperature\nof 150 °C, indicating their high chemical and thermal resistance.\nThe flexibility and performance durability of these composite coatings\nwere demonstrated by a suite of characterization methods, including\nbending, folding, and adhesion tests. Moreover, a high electromagnetic\ninterference shielding (EMI) effectiveness of 73.3 dB is achieved\nfor SA–chitosan/AgNW composite coatings at a thickness of only\n10 μm due to the ultrahigh electrical conductivity. Additionally,\nwe further demonstrated that such conductive composite inks can be\nused for fabricating functional textiles for a variety of applications\nwith high performance, such as EMI shielding, Joule heating, and strain\nsensing. The robust and highly conductive inks prepared by this simple\nand environmental-friendly method hold great promise as important\nmaterial candidates for the potential large-scale manufacturing of\nflexible and wearable electronics.