Improved binding between copper and carbon nanotubes in a composite using oxygen-containing functional groups

The adsorption of Cu on defective carbon nanotubes (CNTs) functionalized with various surface functional groups, including atomic oxygen (-O), hydroxyl (-OH) and carboxyl (-COOH) groups, was investigated by density functional theory calculation. The chemical interaction analysis revealed that the oxygen of the surface functional group can enhance the interaction between the carbon and Cu. The oxygen of the functional group could either promote electron exchange between Cu and carbon atoms, or directly interact with Cu and, thus, played a key role of a glue between the Cu and the CNT surfaces. Among the functional groups investigated, the carboxyl functional group resulted in the largest and most consistent increase in the Cu binding energies on both pristine and defective CNTs. The present calculations support recent experimental work suggesting an important role of interfacial oxygen in the improvement of the mechanical properties of CNT/Cu composites. (C) 2010 Elsevier Ltd. All rights reserved.