Magnetoresistive and piezoresistive polyaniline nanoarrays in-situ polymerized surrounding magnetic graphene aerogel

Herein, a novel three-dimensional nanocomposite aerogel (rGO/Fe₃O₄/PANI NAs) with outstanding magnetoresistance and piezoresistance was manufactured by the in-situ polymerized polyaniline nanoarrays (PANI NAs) surrounding magnetic reduced graphene oxide (rGO/Fe₃O₄) aerogel that was prepared through the combination of hydrothermal method and lyophilization method. This rGO/Fe₃O₄/PANI NAs nanocomposite aerogel with 60 wt.% loading of PANI NAs well preserved the porous structure and gained a superior mechanical strength (121.04 kPa) compared with that of rGO aerogel, rGO/Fe₃O₄ aerogel, and rGO/PANI NAs aerogel (43.54, 58.12, and 116.98 kPa, respectively). The rGO/Fe₃O₄/PANI NAs nanocomposite aerogel could hold its original state with almost 100% recovery ratio after cycling compression tests under 80% of deformation strain at a suitable compression rate of 5 mm min⁻¹. The introduction of PANI NAs into the rGO/Fe₃O₄ aerogel also brought a satisfactory piezoresistive performance with a large gauge factor up to 2.83 and a superb stability for the electrical signal output (which was decreased only 5.80% after 500 compression cycles) to the rGO/Fe₃O₄/PANI NAs nanocomposite aerogel. The loading of Fe₃O₄ and PANI NAs also provided rGO/Fe₃O₄/PANI NAs nanocomposite aerogel with a negative magnetoresistance value up to − 4.37%. The magnetoresistance was explained via the amelioration of spin transport in the material. The unique negative magnetoresistance and excellent piezoresistance make rGO/Fe₃O₄/PANI NAs nanocomposite aerogel a promising candidate for the development of advanced electronic devices. Graphical abstract: A novel three-dimensional nanocomposite aerogel (rGO/Fe₃O₄/PANI NAs) exhibits amazing negative magnetoresistance and outstanding piezoresistive performance. [Figure not available: see fulltext.].