Carbon-based piezoresistive polymer composites: Structure and electrical properties

Mechanical vs. electrical hysteresis of carbon nanotube/styrene–butadiene–styrene composites and their influence in the electromechanical response

“…In fact conductive fillers such as carbon nanotubes, carbon nanofibers or graphene nanofiller, allow modifying size, aspect ratio, porosity/surface area and energy gap, among others, which together with the large range of possible polymer matrix properties, allow fine tuning of the final composite electrical, mechanical, thermal and electromechanical properties, among others [1,2]. In particular, conductive nanofillers on different polymer matrices such as epoxies [3,4], thermoplastics [3][4][5] or thermoplastics elastomers [3,4] allow defining force and deformation response of the piezoresistive sensors [3,4,6].…”

“…In particular, the excellent electrical and mechanical properties of carbon nanotubes (CNT) make them excellent nanofillers for the preparation of conductive polymers [1] and piezoresistive composites, due to the low percolation threshold when compared to others fillers [7]. A fundamental problem on the development of piezoresistive polymer based composites is the linearity between the electrical resistivity variation and the applied strain, commonly known as gauge factor (GF).…”

Graphite nanoplatelets and carbon nanotubes based polyethylene composites: Electrical conductivity and morphology

“…Upon these low acceleration potentials the electrical properties of the material can be obtained, being the image contrast related to the local conductivity [28]. More in detail, under the adopted acquisition parameters (300V, 100 pA) bright and dark regions indicate conductive and non-conductive regions, respectively [21,29]. Once the value of ≈1 kV was exceeded, the contrast begins to be reversed: this means that bright and dark regions appear respectively non conductive and conductive for this kind of materials [21].…”

“…More in detail, under the adopted acquisition parameters (300V, 100 pA) bright and dark regions indicate conductive and non-conductive regions, respectively [21,29]. Once the value of ≈1 kV was exceeded, the contrast begins to be reversed: this means that bright and dark regions appear respectively non conductive and conductive for this kind of materials [21]. The principles of the brightness inversion due to acceleration potentials in SEM are discussed elsewhere by some authors [30].…”

“…More in details, sample cross sections were obtained by means of the ultramicrotome technique (the sample was embedded in epoxy resin to fill voids and to constitute a block, which was then cross sectioned). Microtome slices 0.1-1 µm in thickness representing the cross-section area of the samples, obtained from the block material, were then investigated by low potential SEM [16,21].…”