Tailoring conductive nanofiller alignment for high actuation strain and output force in electroactive polymers.

Zhao, Fengwan; Zhang, Jie; Tian, Hongmiao; Zhu, Ruiyao; Sun, Leyi; Dou, Wencong; Chen, Hansen; Ye, Zuo-Guang et al. · Nat Commun · 2025

basic_science · Level V

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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 Al<sub>2</sub>O<sub>3</sub>-coated carbon nanotubes (Al<sub>2</sub>O<sub>3</sub>@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 Al<sub>2</sub>O<sub>3</sub>@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 Al<sub>2</sub>O<sub>3</sub>@CNTs enhance the local stiffness via 'face-enhanced effect', yielding a high output force per unit volume (1.25 mN/mm<sup>3</sup> 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.