Novel Conductive Hydrogels Incorporating Conjugated Polymer-Single-Walled Carbon Nanotube Complexes as Network Reinforcer and Conductive Filler

Conductive hydrogels incorporating single-walled carbon nanotubes (SWNTs) as conductive fillers are rarely reported, as their poor solution processability poses a major challenge for uniform integration into hydrogel networks. Dispersing SWNTs with conjugated polymers (CPs) improves their solution processability but typically yields dilute dispersions in organic solvents that are difficult to convert into hydrogels. Additionally, the insulating sidechains on CPs often diminish the conductivity of the final material. To address these limitations, we employed a CP featuring self-immolative linkers (SILs) in its sidechains to disperse SWNTs in N,N-dimethylformamide (DMF). This dispersion was then combined with a concentrated polyvinyl alcohol (PVA) solution in dimethyl sulfoxide (DMSO) to form a uniform composite. After concentration via centrifugation and solvent exchange into water, a stable hydrogel was formed through multiple freeze–thaw cycles. The SILs enabled rapid and clean removal of the polymer sidechains upon treatment with tetra-n-butylammonium fluoride (TBAF), resulting in an approximately threefold enhancement in hydrogel conductivity. Moreover, the sidechain cleavage products contributed to hydrogen bonding within the hydrogel network, counteracting the chaotropic effects of TBAF and reinforcing the hydrogel mechanically. This innovative strategy provides a versatile platform for fabricating conductive hydrogels from organic solvents and is readily adaptable to a wide range of polymeric systems, opening new avenues in functional hydrogel design.