Ultrathin Dielectric Elastomer Fibers for Actuation

Fiber-shaped dielectric elastomer actuators can be formed into artificial muscle to realize high actuation forces and large displacements. The actuator needs an electrode geometry which applies radial electric field over the whole fiber length without constraining its deformations. The electrode gap below 20 microns is needed to operate under moderate actuation voltage. In addition, practical fiber actuators would require >4,000 km length to power human size devices, which necessitates approaches for production fibers of the sufficient length, formation fiber bundles with simple and reliable electric connections. Phase I targets tubular fibers with the wall thickness 20 microns and with the road-map to scale it down to 5 microns during the Phase II. A construction of ultrafine fiber actuator addresses identified above challenges by designing inner electrode which provides tensile and radial pre-strains of the elastomer and does not mechanically constraints the elastomer during actuation. Elastomer is selected with elastic modulus in the range of 0.1 to 1 MPa to achieve actuation strains >1% at voltages ~ 300 V and having temperature stability exceeding 60°C. The actuators can be fabricated in large quantities by adopting processes developed for wire and optical fiber coating.