IMPROVING THE SWELLING EFFECT OF COPPER PHTHALOCYANINE SURFACES BY CONTROLLING SURFACE WETTABILITY AND MICROSTRUCTURE USING OXYGEN PLASMA TREATMENT

The sensitivity of quartz crystal microbalance (QCM) can be increased through the swelling effect of the active layer on the QCM surface by increasing the number of adsorbed analyte molecules. In this study, deposition of copper phthalocyanine (CuPc) layer, followed by oxygen plasma treatment can increase the hydrophilicity that promotes surface swelling. Increased wettability can stimulate surface diffusion which plays an important role in the swelling process. The transformation of overlapping and connected fibers into shorter and looser fibers in the surface morphology of CuPc due to the collision of oxygen radical atoms and O₂⁺ ions from oxygen plasma causes an increase in surface roughness. An increase in the swelling effect occurred in samples treated with oxygen plasma proved by the QCM frequency changes using aquadest, phosphate-buffered saline (PBS), and tris-buffered saline (Tris-HCl), where the largest frequency changes occurred in PBS.