ELECTROCHEMICAL-BEHAVIOR AND SURFACE MORPHOLOGIC CHANGES OF COPPER SUBSTRATES IN THE PRESENCE OF 2,5-DIMERCAPTO-1,3,4-THIADIAZOLE - IN-SITUEQCM AND PHASE MEASUREMENT INTERFEROMETRIC MICROSCOPY

Interaction between copper and 2,5-dimercapto-1,3,4-thiadiazole (DMcT) plays a crucial role in the performance of the DMcT-based polymer com posite cathode with a copper current collector. In order to understand this interaction, we employed voltammetry combined with in situ elect rochemical quartz crystal microgravimetry (EQCM) and in situ phase mea surement interferometric microscope (PMIM), and investigated electroch emical behavior and surface morphologic changes of a copper substrate in nonaqueous solutions without and with DMcT. Voltammetric results sh ow that DMcT inhibits electrodissolution of copper at potentials negat ive of 1.0 V vs. SSCE. EQCM results suggest that Cu may dissolve chief ly as Cu+, which may be stabilized by DMcT by forming a complex, at mo re positive potentials than 1.0 V. The PMIM images and corresponding d ata demonstrate that copper dissolution is a nonuniform process and re sults in a roughness increase of surface in the absence of DMcT while the presence of DMcT makes the substrate surface remain relatively smo oth. Scanning electron micrographs further support the PMIM observatio ns.Interaction between copper and 2,5-dimercapto-1,3,4-thiadiazole (DM cT) plays a crucial role in the performance of the DMcT-based polymer composite cathode with a copper current collector. In order to underst and this interaction, we employed voltammetry combined with in situ el ectrochemical quartz crystal microgravimetry (EQCM) and in situ phase measurement interferometric microscope (PMIM), and investigated electr ochemical behavior and surface morphologic changes of a copper substra te in nonaqueous solutions without and with DMcT. Voltammetric results show that DMcT inhibits electrodissolution of copper at potentials ne gative of 1.0 V vs. SSCE. EQCM results suggest that Cu may dissolve ch iefly as Cu, which may be stabilized by DMcT by forming a complex, at more positive potentials than 1.0 V. The PMIM images and correspondin g data demonstrate that copper dissolution is a nonuniform process and results in a roughness increase of surface in the absence of DMcT whi le the presence of DMcT makes the substrate surface remain relatively smooth. Scanning electron micrographs further support the PMIM observa tions.