Dispersion of carbon nanotubes in polymer solutions for the electrospinning technique use

Abstract

Electrospinning via polymeric solutions has been widely used for the production of nanofibrous scaffolds for tissue engineering. Along with the current technological developments, carbon nanotubes (CNTs) have proved to be of great interest to the nanotechnology field, mainly as reinforcing material to provide greater mechanical properties to many different matrices. In the current project, we aim to perform the purification and functionalization of multi-walled carbon nanotubes (MWCNTs) in order to find optimal conditions to further disperse them in polymeric solutions. MWCNTs in powder or deposited on titanium substrates will be produced at the National Institute for Space Research (INPE), at the Associated Sensors and Materials Laboratory, using chemical deposition system via thermal vapour deposition (CVD). Due to the use of catalysts such as ferrocene, the CNTs produced via CVD possess iron particles trapped in their structures. Therefore, to remove these remaining particles, acid baths assisted by ultrasound will be employed. After this purification step, the MWCNTs will be functionalized either via chemical route (nitric and/or sulphuric acids) or by oxygen plasma. Both routes have as a common objective the incorporation of carboxyl and hydroxyl groups on the surface of the MWCNTs, therefore creating a final material with higher polarity and enhanced hydrophilicity. Next, by using the electrospinning technique, nanocomposites will be produced from solutions containing polycaprolactone (PCL), which is a biocompatible and biodegradable polymer, and different proportions of MWCNTs (before purification, after purification and after purification and functionalization). The materials will be characterized via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Spectroscopy Photoelectron X-ray (XPS), Raman Spectroscopy, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Thermogravimetric Analysis (TGA). At the end of the project, we expect to identify the best method for purification and functionalization of MWCNTs for later use as reinforcement agents in a polyester matrix, named PCL, for future tissue engineering applications. (AU)