Augmenting bending stroke of soft dielectric unimorph actuator using carbon nanotubes

Abstract

Experimental investigations are carried out to quantify the effect of carbon nanotubes (CNTs) addition on the actuation performance of polydimethylsiloxane (PDMS) based soft dielectric elastomer actuator (DEA). The actuation ability of pure PDMS and CNT/PDMS composite samples is compared in unimorph configuration. Comparative analysis of experimental results shows that incorporation of optimum CNT concentration (0.05 wt%) significantly enhances the tip displacement (two times) and efficiency (three times) of pure PDMS based DEA. Increasing the CNT concentration beyond optimum level degrades the tip displacement and efficiency of bend actuator. The experimental results are well supported by the theoretical analysis and finite element simulations. Moreover, experimental and numerical findings are combined to establish microstructure-property relationship of DEA. It is shown that at optimum CNT concentration, the induced Maxwell stress compensates for the increase in stiffness of DEA. However, the enhanced stiffness and agglomeration beyond optimum CNT loading results in lower tip displacement.

Soft Actuators Based On Carbon Nanomaterials

“…Baranwal et al studied the influence of doped CNTs on the driving performance of PDMS-based soft DE actuator, and showed with CNT loading of 0.05 wt.%, the efficiency of CNT/ PDMS based DE was obviously higher than that of the pure-PDMS-based, which was ascribed to the increase of dielectric constant compensating for the increase of actuator stiffness. [72] Xu et al prepared a layered DE actuator, of which the conductive layer Ecoflex and the insulating layer multi-walled CNT (MWCNT)-Ecoflex were alternately assembled layer by layer by spin coating. Due to the existence of the insulating layer, a large number of charges were accumulated in the conductive layer during actuation, which greatly increased the dielectric constant of the material and improved the electromechanical sensitivity.…”

“…MWCNT, GO, CNT. [72,73,75] i-EAP Doping with carbon nanomaterials to improve the transmission performance of the ion membrane, or as a surface electrode to increase the interface area with the substrate membrane.…”