Super-phobic surface structures
Superlyophobic Surface Structure, including a substrate having a surface; a plurality of nanoscale raised features on the substrate surface, each nanoscale raised feature having a length measured in a direction approximately perpendicular to the substrate surface, each nanoscale raised feature having a raised feature diameter along the length and measured in a direction approximately parallel to the substrate surface; a nanoscale top feature on each of a plurality of the nanoscale raised features, each nanoscale top feature having a top feature diameter measured in a direction approximately parallel to the substrate surface; in which an average top feature diameter is greater than an average raised feature diameter. Method of fabricating a Superlyophobic Surface Structure.
1. A method, comprising:
providing a multi-layer blank including a substrate layer having a substrate surface, a first layer over the substrate surface, and a second layer over a surface of the first layer;
etching the second layer to form a plurality of spaced-apart nanoscale top features over the surface of the first layer, each nanoscale top feature having a diameter measured in a direction approximately parallel with the substrate surface; and
etching the first layer to form a plurality of nanoscale raised features over the substrate surface, each of the nanoscale raised features supporting one of the nanoscale top features over the substrate surface, each of the nanoscale raised features having a length measured in a direction approximately perpendicular to the substrate surface, and each of the nanoscale raised features having a diameter at a point located along the length near the supported nanoscale top feature and measured in a direction approximately parallel with the substrate surface;
wherein the plurality of nanoscale top features collectively forms a superlyophobic surface over the plurality of nanoscale raised features; and
wherein an average of the diameters of the nanoscale top features is greater than an average of the diameters of each of the nanoscale raised features at the points.
2. The method of claim 1 , wherein the etching includes forming each of the plurality of the nanoscale to features as having a height measured in a direction approximately perpendicular to the substrate surface, and wherein an average of the heights of the nanoscale top features is within a range of between about 50 Angstroms and about 1000 Angstroms.
3. The method of claim 1 , wherein the etching includes forming the plurality of the nanoscale top features with an average of the diameters of the nanoscale top features as being within a range of between about 100 nanometers and about 1000 nanometers.
4. The method of claim 1 , wherein the etching includes forming each of the plurality of the nanoscale raised features as having another diameter at another point located along the length near the substrate surface and measured in the direction approximately parallel with the substrate surface, and wherein each of the plurality of the nanoscale raised features has the another diameter at the another point as being greater than the diameter at the point.
5. The method of claim 4 , wherein the etching includes forming each of the plurality of the nanoscale raised features with the another point being located about one micrometer away from the substrate surface and with the point being located about one micrometer away from the supported nanoscale top feature, and wherein each of the plurality of the nanoscale raised features is characterized by an aspect ratio being defined as the another diameter divided by the diameter, and wherein an average of the aspect ratios is at least about 2:1.
6. The method of claim 1 , wherein the etching the first layer includes forming a post.
7. The method of claim 1 , wherein the etching the second layer includes forming a disk.
8. The method of claim 1 , wherein the etching the first layer includes forming each of the plurality of the nanoscale raised features with the length as being within a range of between about 5 micrometers and about 20 micrometers.
9. The method of claim 1 , wherein the etching the first layer includes forming each of the plurality of the nanoscale raised features as having an average diameter along the length being within a range of between about 100 nanometers and about 1000 nanometers.
10. The method of claim 9 , wherein the etching the second layer includes forming each of the plurality of nanoscale top features with the diameter of the nanoscale top feature as being greater than the average diameter along the length of the nanoscale raised feature.
11. The method of claim 4 , wherein the etching the first layer includes forming each of the plurality of the nanoscale raised features as being tapered from the point to the another point.