Modeling of mesoscale dispersion effect on the piezoresistivity of carbon nanotube-polymer nanocomposites via 3D computational multiscale micromechanics methods

Abstract

In uniaxial tension and compression experiments, carbon nanotube (CNT)-polymer nanocomposites have demonstrated exceptional mechanical and coupled electrostatic properties in the form of piezoresistivity. In order to better understand the correlation of the piezoresistive response with the CNT dispersion at the mesoscale, a 3D computational multiscale micromechanics model based on finite element analysis is constructed to predict the effective macroscale piezoresistive response of CNT/polymer nanocomposites. The key factors that may contribute to the overall piezoresistive response, i.e. the nanoscale electrical tunneling effect, the inherent CNT piezoresistivity and the CNT mesoscale network effect are incorporated in the model based on a 3D multiscale mechanical-electrostatic coupled code. The results not only explain how different nanoscale mechanisms influence the overall macroscale piezoresistive response through the mesoscale CNT network, but also give reason and provide bounds for the wide range of gauge factors found in the literature offering insight regarding how control of the mesoscale CNT networks can be used to tailor nanocomposite piezoresistive response.

Bending Properties of Carbon Nanotube/Polymer Composites with Various Aspect Ratios and Filler Contents

“…In addition, the sensitivity decreased as the MWNT content increased. This is because as the MWNT content increased, the MWNT electrical networks inside the composite were disconnected only by a small portion due to excessive number of MWNTs [ 34 , 35 ]. Furthermore, the sensitivity of 1.0 wt.% H-MWNT/PDMS was greater than that of 1.0 wt.% L-MWNT/PDMS at the same content.…”

“…Furthermore, the sensitivity of 1.0 wt.% H-MWNT/PDMS was greater than that of 1.0 wt.% L-MWNT/PDMS at the same content. This is because the aspect ratio of L-MWNT is smaller than that of H-MWNT, resulting in increased disconnections of the electrical networks in the MWNTs according to the change [ 15 , 35 ]. Therefore, a smaller aspect ratio of MWNT and decreased content (over P c ) are appropriate conditions for an MWNTs/PDMS composite bending sensor for improving the sensitivity.…”

“…The L-MWNT/PDMS composite is more sensitive than the H-MWNT/PDMS composite even at the same content because of the larger aspect ratio and wavy shape of the H-MWNT. The large aspect ratio and the wavy shape played a key role in preventing disconnections of the MWNT networks inside the composite when subjected to bending deformation, thereby mitigating the piezoresistive effect [ 15 , 35 ].…”

Recent Studies on the Multiscale Analysis of Polymer Nanocomposites

“…Therefore, it is possible to more accurately analyze the various physical behaviors and phenomena of polymer nanocomposites based on this analysis. Analysis of the effect of parameters related to the distribution of fillers, such as dispersion [122,[131][132][133][134][135][136][137][138][139][140][141], agglomeration [123,142,143], clustering [144], and volume concentration effect [145] on the physical properties of nanocomposites, as a key factor when inserting nano filler into polymer nanocomposites, is being carried out. The effect of the interphase generated around the filler can be properly interpreted through the multiscale analysis methodology.…”

“…The piezoresistivity [133,134,142,175,[182][183][184][185] and piezoelectricity [154], which are difficult to interpret in the conventional methodology, have been actively studied through the multiscale analysis methodology, which is shown in Figs. 33 and 34.…”