Switching Properties of Mixed Carboxylic Acid Terminated Self Assembled Monolayers on Au(111)

DANIELA KARINA JACQUELIN

Nice

Congreso; 61 Annual Meeting of the International Society of Electrochemistry; 2010

In this work we show that homogeneously mixed self-assembled monolayers (SAMs) of mercaptoalkanoic acids of different chain lengths can be used to build up a pH-sensitive supramolecular switch. The acids with short and long alkyl chains interact via the strong hydrogen bond between carboxylic groups. The pH acts as a trigger by breaking or restoring the hydrogen bond interaction in basic or acidic pHs, respectively. The corresponding changes in the monolayer structure were determined by ellipsometry, surface-enhanced Raman spectroscopy and contact angle measurements. DFT calculations were performed to elucidate the structures of interacting molecules that are compatible with the surface coverage obtained from electrochemical reductive desorption experiments. The simplicity of the preparation procedure assures a high reproducibility whereas the stability of the homogeneous mixed SAM guarantees the reversibility of the switching process.