Highly transparent and low-voltage-driven soft actuators fabricated by laser digital patterning

Laser digital patterning process (LDP) is applied to fabricate highly transparent and low-voltage-driven soft actuators comprising polydimethylsiloxane (PDMS)-Ni electrodes-colorless polyimide (cPI) layers. A highly transparent (transmittance of 80.5% at 550 nm) and a low sheet resistance (15 O sq(-1)) Ni-based actuator is fabricated via laser-induced reductive sintering of a NiOx nanoparticle thin film without employing any vacuum or high-temperature process. Owning to the high conductivity and mechanical stability of the Ni electrodes on cPI, as well as the large difference in the thermal expansion coefficients of cPI and PDMS, the transparent actuator achieves a remarkably large curvature of 1.85 cm(-1 )at a low applied voltage of 17 V and maintains the bending curvature without noticeable changes for 1000 cycles. Different from the conventional actuators, controlling the conductivity of the Ni electrode patterns by simply adjusting the laser parameter during the LDP process allows transparent actuators with the same shape to drive different motions. We also demonstrate that transparent actuators with different shapes can be easily fabricated only by altering the computer-aided design data. Finally, a gripper and a hand-shaped actuator are exemplified as practical applications of the transparent soft actuators.