Single feature made on polished stainless steel surface Suggested palette of box colours – for use if required and to be sized as required Diffractive feature formation on metal Marcus Ardron 304 stainless steel processed in CO2 Single feature made on polished stainless steel surface Marangoni effect: surface tension due to thermal gradient Where: σ = surface tension h = length in temp. grad. η = viscosity α = thermal diffusivity ΔT = temp. difference Thermo-capillary motion: buoyancy, density changes, thermal currents Sim & Kim. Int J Heat Mass Tran 48(2005) 1137-1144 t = non-dimensional time The quantity that must be harnessed Nink et al. Appl Surf Sci 138-139 (1999) 439-443 Balandin et al. J Appl Phys 78(3) 1995 2037-2044 Chemi-capillary motion: diffusion across surface, chemical reactions Periodic structure formed in plated surface Period of 8μm Height excursion of ≈125nm