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Figure 2. Soft conductive nanocomposites based on carbon nanofillers. (A) SEM image of CB powder (left) and the conductivity variation of a CB-PDMS composite under stretching (right). Reproduced with permission from ref^[45]. Copyright 2007, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim; (B) SEM image of graphene foam (GF) (left) and the conductivity of GF and GF/PDMS composites with respect to the number of graphene layers (right). Reproduced with permission from ref^[48]. Copyright 2011, Nature Publishing Group; (C) Schematic illustration of the fabrication of PDMS submicrobead/GO nanocomposite ink (left) and the volume resistivity as a function of GO volume fraction. Reproduced with permission from ref^[68]. Copyright 2019, Elsevier Ltd; (D) Schematic illustration of the fabrication process of GNP/PU nanocomposite films (left) and cross-sectional SEM image of the film (right). Reproduced with permission from ref^[70]. Copyright 2017, American Chemical Society; (E) SEM image of SWCNTs uniformly dispersed in rubber (left) and the conductivity of printed elastic conductor as a function of stretchability with different concentrations of SWCNT (right). Reproduced with permission from ref^[52]. Copyright 2009, Nature Publishing Group; (F) SEM image of a conductive alginate hydrogel with GFs and CNTs (left). Red asterisks indicate regions containing GFs, and yellow arrows point to CNTs. The conductivity of microporous and nanoporous hydrogels with increasing concentrations of carbon fillers (right). Reproduced with permission from ref^[59]. Copyright 2021, The Author(s), under exclusive license to Springer Nature Limited. CB: Carbon black; CNTs: carbon nanotubes; GFs: graphene flakes; GO: graphene oxide; GNP: graphene nanoplate; PDMS: polydimethylsiloxane; PU: polyurethane; SEM: scanning electron microscopy; SWCNT: single-walled carbon nanotube.