Carboxylic Multi-Walled Carbon Nanotubes as Reinforcing Fillers in Ionic Polymer-Metal Composite Actuators with Enhanced Driving Performance

Although huge attentions are paid to the bionic robot research, preparing flexible actuators with high sensitivity, fast response, and long lifespan are still in great challenge. Herein, an enhanced actuator based on the ionic polymer-metal composite (IPMC) and carboxylic multi-walled carbon nanotubes (CMWCNTs) is presented. The nanoscale decoration of MWCNT materials leads to the effectively application of doped and decorated carbon-based devices for actuators. In the study, morphologies of CMWCNTs are evaluated with transmission electron microscope (TEM) and scanning electron microscope (SEM). By the home-setup platform, the electrical conductivity and driving performance are evaluated. Using tensile-testing machine, mechanical properties, such as the elastic modulus and tensile strength, are assessed. Results show that performances including electronic, mechanical, and driving activities of the ionic polymer-metal composite actuator are significantly improved. The maximum output force and sensitivity of the actuators are increased at rates of 24% and 130%, respectively. The mechanism is attributed to carboxylic groups in the acceleration of hydrated cations movement. Additionally, the surface conductivity, mechanical strength, and dispersion are far superior to those walled carbon nanotubes (WCNT)-doped actuators reported previously. IPMC-embedded nanotube designs provide a high potential for the development of robotic-assisted manipulations, such as biomedical robots and microelectromechanical systems.

Automated summary

This study presents an improved actuator based on IPMC and CMWCNTs, where the nanoscale decoration of CMWCNT materials effectively enhances the electronic, mechanical, and driving performance of the actuator, resulting in significant improvements in output force and sensitivity. This enhancement is attributed to the acceleration of hydrated cations movement by carboxylic groups. Moreover, the IPMC-embedded nanotube design shows great potential for the development of robotic-assisted manipulations, such as biomedical robots and microelectromechanical systems.