Note that, since the polymer melt also shows significant elasticity with high viscosity, the elasticity of the liquid can also cause a long-range increase in ∆ƒ and Fcons, not only the density distribution. In fact, the previous quasi-elastic neutron scattering (QENS) on silica-particle-filled PDMS has suggested that a ~5 nm thick layer of liquid molecules is formed on the silica surface, which forms a strong interaction with the surface and brings the extra elasticity of the interface. On the other hand, from the standpoint of solvent tip approximation (STA), the relationship between the conservative forces and the density distribution can be formulated as follows: 𝐹 4125 (𝑧) = 𝑘 D 𝑇 𝜌(𝑧)