Surface functionalization of colloidal particles and carbon nanotubes

Abstract

The application of inert hydrophilic and hydrophobic carbon nanotubes (CNTs) in solution is dependent on the ability of their entities to be functionalized and thereby, improve the properties. Wettability is an important property of the solid surface in practical applications. The wettability of a solid surface is controlled by its chemical composition and geometrical structure and is usually enhanced by surface roughness, especially by fractal structure. Dfferences in wettability are also caused by the dispersive and polar characteristics of the functional groups attached to the CNT surface. Herein, we report the growth and surface functionalization of CNTs using concentrated nitric acid, mixture of concentrated nitric/sulfuric acid and plasma treatment (oxygen and tetrafluoromethane). The functionalized CNTs were characterized using various spectroscopic and microscopic techniques. CNTs are hydrophobic in nature and cannot be dispersed in most solvents. The dispersity of functionalized CNTs in water increased with increase in hydrophilic functional groups on the surface. The effect of functionalization on the hydrophobicity of the surface was also investigated using a goniometer. CNT forest treated with CF4 plasma is hydrophobic to water when compared to the oxygen plasma-treated.