Abstrakt

Effect of pH on the barrier properties of 11-mercapto undecanoic acid and 4-amino thiophenol SAMs on gold

UjjalKumar Sur

To understand the influence of surface charge on the electron transfer properties of ionic SAMs, the effect of pH of electrolytic solutions and applied potential on the barrier properties of 11-mercapto undecanoic acid and 4-aminothiophenol SAMs on gold were carried out. We find that 11- mercapto undecanoic acid SAMexhibits poor blocking behaviour towards ruthenium (III) redox reaction at low pH, but shows excellent blocking behaviour at high pH. On the other hand, the samemonolayer shows excellent blocking behaviour to ferrocyanide redox reaction even at lowpH. On the other hand, 4-aminothiophenol SAM shows poor blocking behaviour towards ferrocyanide and ruthenium (III) redox reaction at low pH, but shows good blocking behaviour at high pH.