Electric field induced ultra-high actuation in a bulk carbon nanotube structure

Strain relaxation and resonance of carbon nanotube forests under electrostatic loading

“…An electrostictive effect might add to the actuation by causing CNTs to elongate as they are polarized. This effect was investigated theoretically for individual CNTs [52,53,54] and recently was studied experimentally on CNT forests by placing them in direct contact between a pair of electrodes held at a potential dif-ference and optionally within a liquid electrolyte [55,56]. However, the electrostrictive effect was observed under strains significantly larger than those exist in the present study ( Fig.…”

“…Therefore, we conclude that the force applied in our experiments is dominated by the capacitive effect. Also, unlike the cited works [55,56], our experiments involve non-contact application of the electric field. As a result, the magnitude of the electrostatic pressure is inversely proportional to the electrostatic gap, and the highest stress exists at the top of the CNT forest, Fig.…”

Giant actuation in bulk carbon nanotubes under coupled electric and magnetic fields

“…7 This polarity dependent actuation of the CNT structure can be observed in the displacement-time graph, as illustrated in Fig. 3b and c. The magnitude of actuation is shown to increase with the increase in the electric eld (applied voltage).…”

“…7,18 These studies demonstrated an even functional relationship of the induced strain with the applied electric eld, thus projecting CNTs as an electrostrictive material. 6,7,18,19 The mechanism involved in electrostrictive behavior is the asymmetrical elongation of the C-C bond resulting in the modication of its hexagonal ring structure. 19 The current carried by MWCNT is because of the outermost shell, whereas the inner shells doesn't contribute to the current ow.…”

“…6 Polarity independent and asymmetrical actuation were also demonstrated in a three-dimensional structure of CNTs, where the ends of the bulk CNTs were embedded in a thin conducting lm of a polymer. 7 The polymer embedded bulk CNTs showed ultra-high actuation at a very low electric eld compared to other studies on CNT polymer composites. 8,9 Moreover, the actuation response in CNT structures can further be enhanced by coupling two different elds i.e.…”