Quantum vacuum photon modes and repulsive Lifshitz–van der Waals interactions

Abstract

The bridge between quantum vacuum photon modes and properties of patterned surfaces is currently being established on solid theoretical grounds. Based on these foundations, the manipulation of quantum vacuum photon modes in a nanostructured cavity is theoretically shown to be able to turn the Lifshitz-van der Waals forces from attractive to repulsive regime. Since this concept relies on surface nanopatterning instead of chemical composition changes, it drastically relaxes the usual conditions for achieving repulsive Lifshitz-van der Waals forces. As a case study, the potential interaction energy between a nanopatterned polyethylene slab and a flat polyethylene slab with water as intervening medium is calculated. Extremely small corrugations heights (less than ten nanometers) are shown to be able to turn the Lifshitz-van der Waals force from attractive to repulsive, the interaction strength being controlled by the corrugation height. This new approach could lead to various applications in surface science. 1 These authors have contributed equally to this work.

Molding Wetting by Laser-Induced Nanostructures

“…Here, the authors are the first, to our knowledge, to report significant change in the wetting properties by subwavelength corrugation. The increase in hydrophobicity caused by fs nano-patterning experimentally confirms the model developed by Dellieu et al [21,22].…”

“…While the responsibility for the change in the dispersion component is doubtful, the corrugation is responsible for all the changes in the CA. However, the magnitude of the effects is too big for such small corrugations, which can be explained with the abovementioned non-classical approach [21,22]. Untreated metal surfaces are generally hydrophilic, but in this experiment they changed to highly hydrophobic by the implementation of sub-micrometer-sized corrugation.…”

“…Classical theory demands the size of corrugation to be above micrometer level in order to achieve super-hydrophobicity. If we assume that a multilayer structure can be imagined as an optical cavity, quantum effects cause the rise of super-hydrophobicity [21,22]. Recently, experimental proof of the impact of nano-corrugation to wetting properties exploiting the Casimir effect has been published [37].…”

“…For metal surface nano-structuring at scales below the plasma wavelength, the Casimir interaction decreases faster than usual for large inter-surface separation, while at short separations an equivalent pressure is larger [23]. The motivation of our study is to experimentally reveal the link between wetting and nano-corrugation [21,22] and to extend the potential application of nanostructures. Surface nanostructures affect the optical characteristics via refractive index on the one hand, while on the other, they influence the wetting characteristics.…”

“…The Casimir force shows application potential in the field of micro-and nano-electromechanical systems-engineered devices, where controlling forces between microscopic bodies or surfaces are crucial for a variety of applications [19,20]. The influence of submicron surface corrugations on Lifshitz-van der Waals forces have been calculated for polyethylene, where surface nano-patterning is responsible for changing the forces from attractive to repulsive [21,22]. For metal surface nano-structuring at scales below the plasma wavelength, the Casimir interaction decreases faster than usual for large inter-surface separation, while at short separations an equivalent pressure is larger [23].…”