Dielectric elastomers (DEs) with high actuated strains at low electric fields have been a great challenge over the past few decades. In this work, we report the preparation of poly(thioether) grafted Ti 3 C 2 T x MXene DE nanocomposites (MXeneK-FGE-BMI) with high area strain at low driving voltage (17.1 %@11.9 V/μm) by two steps: the pretreated MXene (MXeneK) initiated decarboxylative ring-opening polymerization (ROP) of furfuryl glycidyl ether (FGE) and carbonyl sulfide (COS), followed by the Diels-Alder (DA) crossslinking reaction between furan groups and bismaleimide (BMI). The grafting of poly(thioether) chains onto the MXeneK surfaces enables MXeneK well dispersed in the matrix, leading to the significant decrease of dielectric loss (tan δ, below 0.04@10 3 Hz). Low content of MXeneK (below 1.0 wt%) resulted in high ε’ (∼12.3@10 3 Hz) and low elastic modulus (Y, below 0.5 MPa). Therefore, the resultant DE nanocomposite present a high area strain of 17.1 % at a driving voltage of 11.9 V/μm, superior to the previous reports (0.7 %∼10 %@12 V/μm). This work provides a facile strategy to prepare DE nanocomposites with excellent electromechanical performances at low driving voltage.
Haiyuan Yuan,Zupeng Liu,Jundong Song,Soichiro Okamura,John H. Xin,Ming Xue,Titao Jing
Stretchable materials are the foundation of dielectric actuators (DEAs) for artificial muscle. However, the inadequate dielectric constant of stretchable materials has always greatly limited the performance of artificial muscle. Recently, soft fillers have been proposed to improve the dielectric property and preserve the stretchability for softness, aiming to avoid the stiffening effect of traditional rigid fillers. As composites, an amount of interfacial region is generated, which remarkably affects composites’ performance from dielectrics to mechanics. Herein, we demonstrate that the size effect, interfacial binding, and compatibility have a great impact on soft filler doped composites. Particularly, according to the liquid characteristics of soft fillers, we explore an interfacial modification method using surfactants. Composite breakdown strength is thus enhanced 2.2-fold from that in the control group due to the reduction of mismatch between fillers and matrix. Moreover, surfactants alleviate the well-known stiffening effect in small fillers. The area strain of the composites reaches 10.3 ± 0.4% at a low electric field of 7 MV/m, and a soft micropump is successfully assembled. These findings demonstrate a unique and combined interfacial influence of soft filler doped elastomer, which promotes the advancements of the dielectric elastomer artificial muscle.
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