Optimization of Triton X-100 removal and ultrasound probe parameters in the preparation of multiwalled carbon nanotube buckypaper

Highlights: • The optimum ultrasound parameters for the carbon nanotube buckypaper preparation were obtained. • Acid treated carbon nanotubes present better results in terms of dispersion during the buckypaper fabrication. • The more efficient combination of solvents to wash the triton X-100 out of the carbon nanotube network was found. • Porous and conductive buckypapers were successfully fabricated by vacuum filtration process. -- Abstract: A highly porous film composed of a three-dimensional network of multi-walled carbon nanotube (MWCNT), also known as buckypaper (BP), was prepared by vacuum filtration of a well-dispersed suspension of MWCNT/H₂0 with the aid Triton X-100 surfactant. The key contribution of this work is to achieve the best parameters during the preparation of the suspension and find the best way to remove the excess triton X-100 from the nanotube network. The stability of suspension in different pH, the adsorption capacity, and the reusability of MWCNT was also evaluated. The effects of ultrasound parameters on the BP properties were systematically investigated and characterized by Raman Spectroscopy, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), and electric resistivity using a four-point probe technique. In addition, the results of using different solvents to wash the BP after filtration process were analyzed by Thermogravimetric analyses (TGA), Fourier transform infrared spectroscopy (FT-IR), and Field emission gun scanning electron microscopy (FEG-SEM). The optimum condition employed in this work (25 min–40%) exhibited the I_D/I_G ratio of 2.17 and L₀₀₂ of 5.597 nm, which suggests less damage to MWCNT. This study confirms that MWCNT-BP can be used to fabricate high-loading CNT/polymer composites with improved electrical properties.