Kuna, J.J., Voïtchovsky, K.
, Singh, C., Jiang, H., Mwenifumbo, S., Ghorai, P.K., Stevens, M.M., Glotzer, S.C. & Stellacci, F. (2009). The effect of nanometre-scale structure on interfacial energy. Nature Materials 8
Author(s) from Durham
Natural surfaces are often structured with nanometre-scale domains, yet a framework providing a quantitative understanding of how nanostructure affects interfacial energy, italic gammaSL, is lacking. Conventional continuum thermodynamics treats italic gammaSL solely as a function of average composition, ignoring structure. Here we show that, when a surface has domains commensurate in size with solvent molecules, italic gammaSL is determined not only by its average composition but also by a structural component that causes italic gammaSL to deviate from the continuum prediction by a substantial amount, as much as 20% in our system. By contrasting surfaces coated with either molecular- (<2 nm) or larger-scale domains (>5 nm), we find that whereas the latter surfaces have the expected linear dependence of italic gammaSL on surface composition, the former show a markedly different non-monotonic trend. Molecular dynamics simulations show how the organization of the solvent molecules at the interface is controlled by the nanostructured surface, which in turn appreciably modifies italic gammaSL.