Thermal disequilibrium & resonance
Resonance phenomena can be utilized to generate repulsion between atoms at different temperatures
"Resonant Enhancement and Dissipation in Nonequilibrium van der Waals Forces,"
A.E. Cohen and S. Mukamel, Phys. Rev. Lett. 91, 233202 (2003)
Can such a mechanism be used to generate repulsion between plates (made of materials with approiate resonances, and held at different temperatures)?
In principle yes, but only for materials where the equilibrium Casimir attraction is already weak, e.g. for aerogels.
"Dilution and resonance-enhanced repulsion in nonequilibrium fluctuation forces,"