Le nitrure d'aluminium : de la poudre au substrat

Nonisothermal Spreading Dynamics of Self-Rewetting Droplets

“…Additionally, whatever is the stage of the evaporating droplets (both pure and binary liquids), the infrared visualization confirms the fact that the temperature of the droplet is hotter near the triple contact line and colder in the centre (apex). as the thermal conductivity of the ceramic is higher 65,66 . Furthermore, the binary droplets evaporating on the ceramic substrate reached a uniform temperature field much quicker (well before ~3 s) than those deposited on the glass surfaces owing to the higher heat transfer rate.…”

“…Additionally, the thermal activity of self-rewetting droplets, water–1-butanol 5 vol %, on a different heated hydrophilic substrate was examined. The experiments consist of depositing spherical binary alcohol droplets on a heated ceramic (AlN) substrate (different thermal conductivity compared to the glass substrate, ∼100 times higher , ) with volumes from around 3 to 5 ± 0.2 μL and initial temperature of 9 ± 1 °C at two different substrate temperatures, ∼60 and ∼90 °C. The generation of characteristic thermal patterns (heat convection from the edges toward the center) at the interface of the binary alcohol droplets with volumes of 4 ± 0.2 μL at substrate temperatures of ∼60 and ∼90 °C can be clearly observed in Figure a,b, respectively.…”

“…The latter feature was observed for both substrates, that is, glass and ceramic, examined in this study. However, the wavelength of droplets depositing on the ceramic substrate compared to glass increased as the thermal conductivity of ceramic is higher. , Furthermore, the binary droplets evaporating on the ceramic substrate reached a uniform temperature field much quicker (well before ∼3 s) than those deposited on the glass surfaces owing to the higher heat transfer rate. The thermal activity and the generation-presence of characteristic thermal patterns, that is, the number of waves, wavelength, and intensity, at the interface of evaporating self-rewetting droplets were clearly affected by the substrate properties and the applied temperature.…”

“…(volumes 4.6±0.2 μL) on a uniformly heated glass substrate at temperatures of ~90 o C, immediately after contact (~0.05 s), ~0.3, ~0.6 and ~3 s. The scale bar depicts a width of 1.5 mm, for all images.Additionally, the thermal activity of self-rewetting droplets; water-1-butanol 5% vol., on a different heated hydrophilic substrate was examined. Experiments consist of depositing spherical binary alcohol droplets on a heated ceramic (AlN) substrate (different thermal conductivity compared to glass substrate, ~100 times higher65,66 ) with volumes from around 3 to 5 ±0.2 μL and initial temperature 9±1 o C, at two different substrate temperatures:~60 o C and ~90 o C. The generation of characteristic thermal patterns (heat convection from the edges towards the centre) at the interface of the binary alcohol droplets, with volumes of 4±0.2 μL, at substrate temperatures of ~60 o C and ~90 o C, can be clearly observed in Figure 13 (a) and (b), respectively. The thermal patterns observed, on the ceramic substrate, at ~60 o C and ~90 o C, were similar to each other, were described by a wave-fluid ('flowery') movement of characteristic warm/cool regions, which travelled inwards to the centre of the droplet; similar behaviour as seen in the case of glass substrate but clearly with more intensive formation and movement.…”