The adsorption of glycine (Gly) on TiO 2 in the gas phase and the behavior of a set of preadsorbed diglycine (Gly-Gly) molecules in solution are studied by using classical nonreactive and reactive (ReaxFF) simulations. The initial dynamic phase of Gly adsorption is rendered through the nonreactive evaporation of a droplet followed by reactive dynamics of the deposited peptide layer. Gly adsorbs strongly on the surface in a wide variety of orientations which are dominated by a carboxyl bidentate coordination to two titanium ions. The binding mode involves mainly anionic species, which are formed after transferring a proton to the surface. Gly zwitterions are present in the second layer. In the time scale explored, water activity does not perturb substantially the orientation of preadsorbed Gly-Gly molecules which remain strongly bound to the substrate through their carboxyl groups. The results of this investigation are in satisfactory agreement with previous theoretical studies and available experimental data.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films