Boundary Lubricants with Exceptionally Low Friction Coefficients Based on 2D Close-Packed Phosphatidylcholine Liposomes



original image

Liposomes of hydrogenated soy phosphatidylcholine (PC) lipids spontaneously self-assemble in close-packed layers on solid surfaces to form boundary lubricants that reduce the coefficient μ of sliding friction between them down to μ ≈ 10−4 – 2 × 10−5, at pressures up to ca. 12 MPa. This strikingly low value is attributed to hydration-lubrication by the PC headgroups exposed at the surfaces of the gel-phase vesicles.