Dust proof properties of spinodal porous surfaces

With an aim of dust proof in optical coating, contact force with spinodal porous surfaces was investigated by counting the number of particles after exposure to a practical circumstance and by directly measuring the contact forces with a probe of Au sphere using an atomic force microscope (AFM). The interaction between the oiled particles and the porous surface was also investigated on an antireflection coating using greases containing particles of polytetrafluoroethylene (PTFE). It was found that the porous structure played the role of adsorbing oil and lowering the contact force between the particles and the surface without deterioration of the antireflection. The contact force was treated based on the liquid bridges between the particles and the surface, and the contribution from the term of Laplace pressure is inferred to be lowered due to the reduced width of the silica skeletons.