Fabrication and testing of functionalized multi-walled carbon nanotubes/deproteinized natural rubber composites for bending actuation under electric field

Abstract

Compliant electrodes (CEs) were prepared from deproteinized natural rubber (DPNR) and multi-walled carbon nanotubes (MWCNTs) using Triton X-100 as a dispersing agent. Dielectric elastomers (DEs) were fabricated, from the DPNR incorporated with functionalized MWCNTs as a high dielectric constant filler, by film casting and the UV-curing process. The effect of MWCNT concentrations on mechanical and electrical properties of the CEs and DEs were individually examined. The defection responses and the dielectrophoresis forces of DEs and DEs attached on one side with CEs (DEs/CEs) were investigated as functions of electric field strength. The 5% v/v MWCNTs composite (CE_5) showed the highest conductivity of 19.7 S/cm and was subsequently used in the DEs/CEs bending experiment. The 2.5 phr of functionalized MWCNTs composite (DE_2.5) showed the highest dielectric constant of 15.4, but a relatively low bending actuation due to its initial high rigidity. The DE_1/CE_5 bilayer composite possessed the highest bending actuation, namely the largest bending distance and the dielectrophoresis force, presumably from the additional polarizations within CE_5 and the interactions with DE_5.