Hybrid EAPap actuator coated with multi-walled carbon nanotubes

Electro-Active Paper (EAPap) materials based on cellulose are attractive for many applications because of their low voltage operation, lightweight, dryness and low power consumption. In addition, EAPap materials are bio-degradable that is important property for artificial muscle actuators as bio-mimetic actuators with controlled properties and shapes. EAPap actuators have been made using cellulose papers coated with thin electrode layers. This actuator showed a reversible and reproducible bending movement. In order to improve both displacement and force of this, complementary conjugated novel material, composed of conductive polymer and carbon nanotubes, is coated on both sides of EAPap. This composite coated EAPap is termed as hybrid EAPap. Used composite consist of multi-walled carbon nanotubes (MWNT) and polyaniline (PANi). It is expected that the use of MWNT can enhance the stiffness of the tri-layered actuator as well as improving the force output. Furthermore, the presence of the MWNT/PANi electrodes may increase the actuation performance of the EAPap material. MWNTs are dispersed in NMP (l-Methyl-2-pyrrolidine), and the resulting suspension is mixed and sonicated with anion doped PANi. Obtained MWNT/PANi/NMP solution is cast on the EAPap by spin coating, and it is dried in a vacuum oven. The effect of processing parameters on the final performance of the composite electrodes is assessed and quantified in terms of the electrical conductivity under dc and ac measurement conditions. The actuation output of the MWNT/PANi/EAPap samples is tested in an environmental chamber in terms of free displacement and blocking force. The performance of the hybrid actuators is also investigated in terms of frequency, voltage and humidity to help shed light on the mechanism responsible for actuation. Comparison of these results in that of the EAPap with PANi and EAPap are also accomplished.