Oxidation functionalization of multiwalled carbon nanotube by mild acid sonication

Multiwalled carbon nanotube (MWCNT) has excellent properties in thermal and electrical conductivities, high tensile strength and surface area and low mass over volume. However, the usage is still limited due to its inert characteristic. MWCNT surface is hydrophobic and not miscible in most solvents. This work emphasize on simple and practical method of functionalization by sonication in mild acid condition. 6M of Nitric acid and Sulfuric acid mixture (Method I) and 6M of Nitric acid (Method II) were demonstrated as an oxidizing agent to introduce carboxyl functional group on MWCNTs surface. Both type of functionalization has demonstrated carboxyl formation but functionalization in acid mixture was chosen to be used for further study for aptamer immobilization. FTIR and SEM have been used to investigate the binding properties and surface morphology respectively. The functionalization time has also been studied by using dispersability test which resulted in good dispersion after 1 hour of functionalization.