Changing the Surface Characteristics of CNF, from Hydrophobic to Hydrophilic, via Plasma Polymerization with Acrylic Acid
Carbon nanofibers (CNF) were surface coated with a thin layer of poly (acrylic acid) (PAA) via plasma polymerization of acrylic acid (AA). The plasma polymerization treated CNF resulted in a significant change of its surface characteristics from hydrophobic to hydrophilic due to the polar groups in PAA-coating layer. Dispersion tests in water and ethanol confirmed a marked change in the hydrophobicity of the treated CNF. In addition, FTIR results showed a new signal for the treated CNF at 1046 cm-1, assigned to C-O groups and represented the presence of PAA. Morphology results by scanning electron microscopy (SEM) revealed that the untreated CNF has a very smooth surface, whereas the treated CNF showed certain roughness on its surface due to the deposited PAA coating layer.PAA coating on the treated CNF was also observed by transmission electron microscopy (TEM) and its thickness was determined to be between 14 to 18 nm. Dynamic Light Scattering (DLS) was used to show that plasma polymerization improved the dispersion of treated CNF and prevented its agglomeration in water versus the poor dispersion observed with untreated CNF.
Velumani S., R. Asomoza and Umapada Pal
E. Hernández-Hernández et al., "Changing the Surface Characteristics of CNF, from Hydrophobic to Hydrophilic, via Plasma Polymerization with Acrylic Acid", Journal of Nano Research, Vol. 9, pp. 45-53, 2010