Long-range wetting transparency on top of layered metal-dielectric substrates
Journal Article - Open Access
MIT Lincoln Laboratory Lexington United States
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It has been recently shown that scores of physical and chemical phenomena including spontaneous emission, scattering and Frster energy transfer can be controlled by nonlocal dielectric environments provided by metamaterials with hyperbolic dispersion and simpler metaldielectric structures. At this time, we have researched van der Waals interactions and experimentally studied wetting of several metallic, dielectric and composite multilayered substrates. We have found that the wetting angle of water on top of MgF2 is highly sensitive to the thickness of the MgF2 layer and the nature of the underlying substrate that could be positioned as far as 100nm beneath the waterMgF2 interface. We refer to this phenomenon as long range wetting transparency. The latter effect cannot be described in terms of the most basic model of dispersion van der Waals-London forces based on pair-wise summation of dipole-dipole interactions across an interface or a gap separating the two media. We infer that the experimentally observed gradual change of the wetting angle with increase of the thickness of the MgF2 layer can possibly be explained by the distance dependence of the Hamaker function describing the strength of interaction, which originates from retardation of electromagnetic waves at the distances comparable to a wavelength.
- Electricity and Magnetism
- Laminates and Composite Materials
- Physical Chemistry