Tailoring conductive nanofiller alignment for high actuation strain and output force in electroactive polymers
Fengwan Zhao, Jie Zhang, Hongmiao Tian, Ruiyao Zhu, Leyi Sun, Wencong Dou, Hansen Chen, Zuo‐Guang Ye, Chenglin Yi, Xiaoming Chen
Abstract
An intrinsic conflict between high deformability and rigidity hinders the development of electroactive polymer (EAP)-based soft robots. Here, we employ an external electric field to align Al2O3-coated carbon nanotubes (Al2O3@CNTs) in a poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) matrix. Compared with pure P(VDF-TrFE-CTFE), the thickness strain of nanocomposites with horizontally and vertically aligned Al2O3@CNTs increases by 473% and 814%, respectively. It results in a high bending angle up to 215° for their actuator beams. Importantly, the horizontally aligned Al2O3@CNTs enhance the local stiffness via ‘face-enhanced effect’, yielding a high output force per unit volume (1.25 mN/mm3 at 30 V/μm). It is not only ~346% higher than pure P(VDF-TrFE-CTFE) but also higher than the reported ceramic actuators. Accordingly, the soft robots made by the designed nanocomposite actuators could climb slopes up to 52° and carry loads equivalent to eight times their body mass. Consequently, this modulating strategy develops a high-performance actuation for soft robots. Electroactive polymers can be used for soft robotics, though it is challenging to balance rigidity and deformability. Here the authors designed a polymer composite using an electric-field assisted tape-casting method to orient the Al2O3-coated carbon nanotubes to tailor the dielectric and mechanical properties.