Articles for manipulating impinging liquids and methods of manufacturing same
This invention relates generally to an article that includes a non-wetting surface having a dynamic contact angle of at least about 90°. The surface is patterned with macro-scale features configured to induce controlled asymmetry in a liquid film produced by impingement of a droplet onto the surface, thereby reducing time of contact between the droplet and the surface.
1. An atomizer comprising a non-wetting surface having a dynamic contact angle with a liquid of at least about 90°, said surface comprising non-wetting features, said surface patterned with macro-scale features having a length scale L m that is larger than a length scale L n of the non-wetting features, the macro-scale features being configured to induce controlled asymmetry in a liquid film produced by impingement of a droplet onto the surface, thereby reducing contact time t c between the droplet and the surface to a value lower than
2.2
(
ρ
R
3
γ
)
1
/
2
(
1
+
ϕ
4
)
,
where the droplet has a radius R, density ρ, surface tension γ, and the patterned surface having a pinning fraction φ of zero.
2. The atomizer of claim 1 , wherein the non-wetting surface is supermetallophobic.
3. The atomizer of claim 1 , wherein the droplet comprises a molten metal.
4. The atomizer of claim 1 , wherein L m /L n is 10 or greater.
5. The atomizer of claim 1 , wherein L m /L n is 100 or greater.
6. The atomizer of claim 1 , wherein L m /L n is 1000 or greater.
7. The atomizer of claim 1 , wherein L m /L n is 10,000 or greater.
8. The atomizer of claim 1 , wherein the non-wetting surface is superhydrophobic.
9. The atomizer of claim 1 , wherein the non-wetting features having the length scale L n comprise non-wetting features having a second scale disposed thereon, wherein the second scale is smaller than L n .
10. The atomizer of claim 9 , wherein L m /L n is greater than 10.
11. The atomizer of claim 9 , wherein L m /L n is greater than 100.
12. The atomizer of claim 1 , wherein the macro-scale features comprise non-wetting features thereon.
13. The atomizer of claim 12 , wherein the non-wetting features comprise non-wetting features having a second scale disposed thereon, wherein the second scale is smaller than L n .
14. The atomizer of claim 1 , wherein the contact time t c is more than 50% below
2.2
(
ρ
R
3
γ
)
1
/
2
(
1
+
ϕ
4
)
.
15. The atomizer of claim 1 , wherein the non-wetting features comprise random or patterned surface roughness.