A Multifunctional MWCNTs-Reinforced Chitosan-Gelatin Conducting Hydrogel for Triboelectric Nanogenerator and...

Hydrogel systems uniting electrical conductivity, sensory responsiveness, and mechanical integrity are emerging as foundational building blocks for next-generation bioinspired electronics. Triboelectric nanogenerators (TENGs) represent a particularly attractive avenue for recovering ambient mechanical energy, while optoelectronic neuromorphic synapses offer energy-efficient, in-sensor optical processing reminiscent of biological visual pathways. In this work, a chitosan-gelatin (CSG) conducting hydrogel is prepared via solution casting and reinforced with carboxyl-functionalized MWCNTs and NaCl. The functionalized nanotube network establishes strong interfacial interactions within the biopolymer matrix, yielding a material with controlled swelling behavior, adequate mechanical resilience with favorable viscoelastic characteristics. The concurrent ionic-electronic transport pathways and elevated charge mobility underpin a well-defined structure-property relationship, translating directly into efficient mechanical-to-electrical energy conversion. The fabricated TENG achieves an open-circuit voltage of ∼398 V, short-circuit current of ∼96 µA, and power density of ∼132.91 µW/cm², maintaining stable output over 10,000 mechanical cycles. The same hydrogel, configured as a two-terminal optoelectronic device, reproduces key synaptic behaviors including short-to-long-term memory transition (STM-LTM) and paired-pulse facilitation (PPF) of ∼120% under optical stimulation. Collectively, this bio-derived hydrogel platform bridges triboelectric energy harvesting and neuromorphic optoelectronic sensing within a unified material system, charting a viable course toward self-powered, brain-inspired sensory electronics.