Fig. 2

Illustration of conductive network formation strategies for high conductivities. a, b) Pure conductive polymer hydrogel fabrication using an additive. a DMSO addition supports formation of physically interconnected PEDOT:PSS network during dry-annealing. Reproduced with permission from [88], copyright Springer Nature, 2020. b DBSA micelle addition causes rearrangement of PEDOT:PSS colloidal particles and formation of a physically interconnected conductive hydrogel network within few minutes. Reproduced with permission from [91], copyright John Wiley and Sons, 2019. c Percolating conductive network hydrogel fabrication from a pure conductive polymer hydrogel. The monomer, crosslinker, and initiator can be infiltrated into the pure conductive polymer hydrogel and cause secondary network formation while maintaining primary percolating conductive network. Reproduced with permission from [93], copyright Springer Nature, 2018. d Fabrication of a percolating conductive network hydrogel from non-conductive hydrogel. PEDOT:PSS can be dispersed in the precursor solution. After crosslinked PVA network formation using glutaraldehyde (GA), acid treatment causes the rearrangement of PEDOT:PSS colloidal particles and formation of a secondary percolating conductive network. Reproduced with permission from [99], copyright John Wiley and Sons, 2022. e Spatial separation of conductive nanocomposite using microgel. Ag nanoparticles are only produced on the surface of the microgel through in situ reduction and a densely packed Ag nanoparticle percolating network is produced after microgel assembly. Reproduced with permission from [100], copyright John Wiley and Sons, 2019. f Spatial separation of conductive nanocomposite using freezing. CNT and GO are located in the surrounding region of ice crystal during freezing. This improves the percolating conductive network and can be maintained by crosslinking at ambient conditions. Reproduced with permission from [102], copyright John Wiley and Sons, 2022