Ultra‐Thin and Conformable Electrodes Composed of Single‐Walled Carbon Nanotube Networks for Skin‐Contact Dielectric Elastomer Actuators

Abstract

Abstract Skin‐contact dielectric elastomer actuators (DEAs) consisting of skin‐conformable, stretchable electrodes are fabricated using a roll‐to‐roll‐based gravure coating method. In this method, single‐walled carbon nanotubes (SWCNTs) are continuously applied on a free‐standing ultra‐thin film (nanosheet) of poly(styrene‐b‐butadiene‐b‐styrene) (SBS) to produce an SWCNT‐SBS nanosheet of 101‐nm thickness. After the first SWCNT coating, the SWCNT‐SBS nanosheet shows a Young's modulus (i.e., 80.9 MPa) comparable to that of the SBS film and a sheet resistance of 4.6 kΩ sq−1. Using the free‐standing SWCNT‐SBS nanosheets as electrodes, a ten‐layered DEA is fabricated without glue or dielectric elastomer precursors on three substrates with different stiffness, namely glass, Ecoflex 00–30, and a urethane elastomer model skin. The low flexural rigidity of the ten‐layered DEA (105 nN m) ensures conformability to the shape of an index finger. Application of an actuation voltage of 2100 V produces a two‐fold larger displacement of the DEA on the Ecoflex 00–30 substrate compared with that on the glass substrate. The ability of the DEA to conform to the surface of skin will enable its application in skin‐contact haptic devices.

Keywords

• carbon nanotubes
• dielectric elastomer actuators
• gravure coatings
• polymer nanosheets
• Young's modulus