Electroconductive hydrogel and devices with conducting polymers assembled around a 3d nanofiber framework

A method for forming an electroconductive hydrogel comprising the steps of:

• dispersing aramid nanofibers (ANFs) in dimethyl sulfoxide (DMSO);
• conducting a solvent exchange with water to generate hydrogels with connective 3D fibrillar networks that serve as templates for the assembly of conducting polymers;
• incorporating polyvinyl alcohol (PVA) during the processing of the hydrogels to weld the fibrillar joints via hydrogen bonding;
• infiltrating monomers into the nanoporous hydrogels in an aqueous media;
• and
• polymerizing the hydrogels with added oxidants.

A method of forming a bioelectrode pattern comprising the steps of:

• masking ANF-PVA hydrogel samples with waterproof adhesive tapes;
• treating the masked hydrogel samples with Py and FeCl3 solutions;
• and
• incorporating PPy into the ANF-PVA matrix only in the area exposed by the mask, leading to custom patterns of CNH.

A method for preparing conductive ANF-PVA hydrogels comprising the steps of:

• dissolving Kevlar para-aramid pulp and PVA in dimethylsulfoxide (DMSO) under magnetic stirring at 95° C. for 7 days;
• dissolving Kevlar para-aramid pulp and PVA in dimethylsulfoxide (DMSO) under magnetic stirring at 95° C. for 7 days;
• mixing the resulting ANF and PVA liquids;
• pouring the mixture into a mould or casting the mixture on a flat steel plate using a film coater;
• and
• solidifying the ANF-PVA mixture through solvent exchange in deionized (DI) water for 24 hours.

A method for patterning ANF-PPy as a custom-built bioelectrode, comprising the steps of:

• preparing a PDMS mold with microchannels by microfabrication techniques;
• placing the PDMS mold face down on a water-soluble tape,
• infusing an ANF dispersion into the microchannels;
• generating a patterned ANF hydrogel by soaking the PDMS in water for both the removal of the tape and solidification of the ANF dispersion;
• and
• embedding a final ANF-PPy pattern within the PDMS channel through the incorporation of PPy into the hydrogel network by sequential treatment with Py and FeCl3 solutions.

A method of producing ANF-PVA hydrogels for NHSE comprising the steps of:

• separately dissolving Kevlar para-aramid pulp and PVA in dimethyl sulfoxide (DMSO) under magnetic stirring at 95° C. for 7 days, respectively;
• mixing the ANF and PVA dispersions a ratio of 1:1;
• pouring the mixture into a mold;
• allowing an exchange of DMSO with deionized water;
• controlling the solid content of the hydrogel by diluting the ANF/PVA mixture with DMSO or evaporating excess DMSO in vacuum oven;
• wherein the PVA hydrogels are prepared using a freeze-thaw method in which PVA aqueous solution is poured into a mold and then frozen at −24° C.;
• thereafter the frozen mixture is thawed at room temperature and repeating the PVA freeze-thaw cycles at least five times.

A 3D interfacial solar evaporators (ISE) using a kirigami-based hydrogel solar evaporator (KHSE) comprising:

• a substrate formed from a mechanically robust hydrogel membrane based on aramid nanofibers (ANF);
• periodic triangular notches on the substrate to form 3D conical arrays under strain;
• and
• biomimetic microstructures on the conical arrays to realize localized crystallization at their peak.

A method of forming a 3D interfacial solar evaporator using a kirigami-based hydrogel solar evaporator (KHSE) comprising the steps of:

• forming a hydrogel membrane assembled with an aramid nanofiber (ANF) network incorporating polyvinyl alcohol (PVA) via solution-based processing;
• coating the network with polypyrrole (PPy) for photothermal conversion to achieve a resultant hydrogel membrane;
• and
• laser engraving the membrane with periodic triangular notches to form 3D conical arrays of the KHSE.