Electrochemical detection of the thermal stability of n-alkanethiolate monolayers on Au(111)

The van der Waals Interactions of n‐Alkanethiol‐Covered Surfaces: From Planar to Curved Surfaces

“…Theposition of the desorption peak in the RD process can be considered as ameasure of the electrochemical stability of the SAM, reflecting ag lobal free energy change between the initial and final states.D oneux et al [9] proposed am ore realistic description for the reductive desorption process: [9][10][11] RS instead of the simplified Equation (1), where the aggregation state of every species is defined specifically. [9] Thus,t he energetic contributions that should be considered are the following:1 )substrate-adsorbate interaction (Au(hkl) À S; determined by the head-group/surface binding energy); 2) lateral interactions (C n /vdW Au(hkl) ;m ainly attractive vdW forces that contribute to stabilise the monolayer,shifting the RD potential towards more negative values); [12,13] 3) substrate/SAM-solvent (potential of zero charge of thiol-solvent interactions in the adsorbed state,p zc CnT-Au(hkl) ); 4) desorbed surfactant-solvent (C n /solvent;A Ts olvation energy);a nd 5) substrate-solvent, (pzc bare Au(hkl) ;d irectly dependent on the difference between the applied potential and the pzc of the bare gold surface). [9] Thec ontributions 1-3 are attributed to the initial state of the process described in Equation (2), whereas 4-5 are to the final state.Therefore,the RD potential peak depends on:…”

Thermal and Chemical Stability of n -Hexadecanethiol Monolayers on Au(111) in O 2 Environments

“…A peak at around -0.9 V has been observed for different SAMs [20,36,37] and has been attributed to the reductive desorption of small amounts of atomic S. Peak C is not observed in freshly prepared C16T monolayers at RT indicating the absence of adsorbed S atoms on the surface as it is confirmed in the HR-XPS spectra. After heating at 443 K, a remarkable diminution of the RD peaks is observed together with an important increase of peak C (inset in Fig.…”

“…The hydrogen atoms of H 2 S originate from the partial dehydrogenation of the alkyl chains at high temperatures. Electrochemistry provides a valuable tool to quantify the sulfur content of the surface from reductive desorption current peaks of sulfur and alkanethiolate species as we have shown in previous works [20,21].…”

The van der Waals Interactions of n‐Alkanethiol‐Covered Surfaces: From Planar to Curved Surfaces

“…instead of the simplified Equation (1), where the aggregation state of every species is defined specifically . Thus, the energetic contributions that should be considered are the following: 1) substrate–adsorbate interaction (Au( hkl )−S; determined by the head‐group/surface binding energy); 2) lateral interactions ( C n /vdW Au( hkl ) ; mainly attractive vdW forces that contribute to stabilise the monolayer, shifting the RD potential towards more negative values); 3) substrate/SAM–solvent (potential of zero charge of thiol‐solvent interactions in the adsorbed state, pzc CnT‐Au( hkl ) ); 4) desorbed surfactant–solvent ( C n /solvent; AT solvation energy); and 5) substrate–solvent, (pzc bare Au( hkl ) ; directly dependent on the difference between the applied potential and the pzc of the bare gold surface) . The contributions 1–3 are attributed to the initial state of the process described in Equation (2), whereas 4–5 are to the final state.…”