Competing interactions in self-assembled monolayers containing peptide groups: molecular dynamics studies of long-chain perfluoro mercaptans on Au(111)

The structure of self-assembled monolayers of a long-chain perfluoro mercaptan was studied by using mol. dynamics simulations. The particular system studied (e.g., perfluorooctyl mercaptoethylamide) was chosen because it offers the possibility of generating a Teflon-like coating on top of a polar film consisting of H-bonded peptide groups. The authors find the monolayer consists of close-packed perfluoroalkanes standing more or less upright and of H-bonded chains of peptide groups. The intramol. flexibility of the mol. enables it to form H bonds with the peptide O and N sepd. by .apprx. 2.8 .ANG. and to accommodate simultaneously the 5.8 .ANG. spacing of the tails. From the mol. dynamics simulations, the authors have also detd. the spectrum of the motion of the polarization assocd. with the peptide groups. [on SciFinder (R)]