Different types of crystalline carbon nanomaterials were used to reinforce polyaniline (PAni) for use in electromechanical bilayer bending actuators. The objective is to analyze how the structural properties of the nanocarbons affect the in-situ produced PAni structure and subsequent final composite actuator behavior. Nanocarbons investigated were multiwalled carbon nanotubes, nitrogen-doped carbon nanotubes, helical-ribbon carbon nanofibers and graphene oxide, each one presenting different shape and structural characteristics. Films of nanocarbon-PAni composite were tested in a liquid electrolyte cell system. Experimental design was used to select type of nanocarbon filler and composite loadings that showed a good balance of electromechanical properties. Raman spectroscopy suggests good interaction between PAni and the nanocarbon fillers.Electron microscopy showed best nanofiller dispersion for graphene oxide, followed by multiwall carbon nanotubes. On the contrary, nitrogen doped nanotube composites showed dispersion problems, and thus a poor performance. Multiwall carbon nanotubes composite actuators had the best performance based on the combination of bending angle, bending velocity and maximum working cycles (measured considering nanofiller loading and applied voltage), while graphene oxide attained similar good performance.

Abstract

We report a method for the efficient anchoring of cadmium selenide (CdSe) nanoparticles on the surface of different types of multi-walled carbon nanotubes (purified, N-doped, O-doped and exfoliated). Characterization using different types of electron microscopies (SEM, STEM, and TEM), energy dispersive spectroscopy (EDS) and x-ray diffraction showed well anchored CdSe nanoparticles (NP) on the nanotube surfaces, NP shapes and sizes varied with temperature and other synthesis conditions, and formed with good yields. The method here reported does not require previous activation of the carbon nanotube surface by chemical functionalization, nor the use of organic solvents, and the reaction proceeded in aqueous solutions, making this process simpler and more environmentally friendly than others.