Compressive strain sensing using carbon nanotube/graphene nanoplatelet/PDMS hybrid nanocomposites

Abstract

One of the features of carbon nanomaterials, namely, exfoliated graphite nanoplatelets (xGnPs) and multi-walled carbon nanotubes (MWCNTs), is their ability to form electrically conductive networks in insulating polymers. Here, we fabricated hybrid nanocomposites consisting of xGnPs, MWCNTs and PDMS with varying xGnP:MWCNT ratios and measured the electrical resistance change when subjected to cyclic loading at two different levels of compressive strain. All the samples showed a decrease in electrical resistance when compression was applied, known as piezoresistive behavior, and the electrical response matched well with the cyclic compressive strain. We found that sensitivity increases with increasing xGnP:MWCNT ratio, which implies that as the proportion of xGnP increases, it is easier to disrupt the conductive network formed by the nanomaterials under the same loading conditions. Depending on the xGnP:MWCNT ratio, we obtained a sensitivity range of 2.2∼3.7, which is similar to the range covered by conventional metal-foil-based strain gages. This suggests the ratio between 1D and 2D conductive fillers can be used as one of design parameters to tailor the sensitivities of nanocomposite strain sensors. Copyright 2016. Used by the Society of the Advancement of Material and Process Engineering with permission.