Direct-ink-writing of multi-functional dynamic polymer-carbon nanotube hydrogel composites

Abstract

Additive manufacturing of conductive hydrogel composites has huge potential in developing advanced materials. Herein, we report a hydrogel composite system integrating multiwalled carbon nanotubes (MWCNTs) into a dynamically crosslinked polymer network. The hydrogel matrix was constructed via hydrogen bonding and reversible aminal linkages formed between aldehyde-functionalized poly(MAA-co-OEGMA) copolymers and linear polyethyleneimine (L-PEI). Optimization of crosslinking density and molecular weight of L-PEI yielded hydrogels with enhanced mechanical strength, tuneable swelling behaviour and robust shear-thinning properties. The incorporated MWCNTs are homogenously dispersed via dual surfactant/polymer stabilization, resulting in the hydrogel composite exhibiting significant mechanical reinforcement (370% increase in modulus), frequency-dependent impedance behavior, and programmable printability, demonstrating its potential for applications in soft electronics and wearable sensors.