Improved Polymer Encapsulation on Multiwalled Carbon Nanotubes by Selective Plasma Induced Controlled Polymer Grafting

Surface graft polymerization on multiwalled carbon nanotubes (MWCNTs) with several grafting mechanisms is nowadays a demanding field of nanocomposites in order to enhance the load carrying capacity, thus improving the overall performance of the composites. Here, we demonstrate the covalent grafting of a sulfonic acid terminated monomer, 2-acrylamido-2-methylpropane sulfonic acid onto sidewalls of MWCNTs via a comparative study between oxygen plasma induced grafting (OPIG), nitrogen plasma induced grafting (NPIG), and nitrogen + oxygen plasma induced grafting (NOPIG) with the aim to identify the most effective process for the preparation of polymer encapsulated carbon nanotubes. From the detail surface analysis, it has been noticed that NOPIG offered much better surface grafting than that of the OPIG and NPIG. The transmission electron microscopy (TEM) images showed that MWCNTs modified by NOPIG possess much thicker and uniform polymer coatings throughout. From thermogravimetric analysis (TGA), the grafting degree was found to be ~80 wt % for the NOPIG sample.