Recently we have been able to show two advances in the creation of realistic models of the Gram negative bacterial outer surface for use in biophysical and structural studies. First we have incorporated smooth (O-antigen containing) lipopolysaccharides into our silicon supported membrane models. Secondly, we have improved the ease of floating bilayer production by depositing the asymmetric LPS containing membrane mimetics below a thiol-alkane self assembled monolayer. Here we wish to combine these advances to examine free floating, asymmetric, smooth LPS containing membranes and use these systems to re-examine the effect on the Gram-negative bacterial outer membrane of divalent cation sequestration.