Slippery liquid-infused porous surfaces having improved stability
Methods and articles disclosed herein relate to liquid repellant surfaces having selective wetting and transport properties. An article having a repellant surface includes a substrate comprising surface features with re-entrant curvature and an immobilized layer of lubricating liquid wetting over the surface features. The surface features with re-entrant curvature can be designed to provide high repellency even after failure or removal of the immobilized layer of lubricating liquid under certain operating conditions.
1. A repellent surface comprising:
a substrate having a plurality of surface features comprising pores containing re-entrant curvature, wherein the surface feature containing re-entrant curvature have an opening diameter that is smaller than the interior pore diameter measured at the center of the pore; and
a lubricating liquid that has a chemical affinity to the substrate, as determined by an equilibrium contact angle of less than 90 degrees, to spontaneously infuse into, wet and stably adhere to said substrate having a plurality of surface features containing re-entrant curvature,
the lubricating liquid wetting and adhering to the plurality of surface features containing re-entrant curvature to provide a stabilized liquid at a thickness sufficient to form a liquid overlayer above the plurality of surface features containing re-entrant curvature,
wherein the plurality of surface features containing re-entrant curvature are effective to substantially stably immobilize the lubricating liquid between, on and over said substrate having a plurality of surface features containing re-entrant curvature, without dewetting from the substrate, to form a repellant surface.
2. The repellent surface of claim 1 , wherein the surface features containing re-entrant curvature have a pore opening angle that is between 0 and 90°.
3. The repellent surface of claim 1 , wherein the surface features containing re-entrant curvature have a pore opening angle that is between 45 and 80°.
4. The repellent surface of claim 1 , wherein the surface features containing re-entrant curvature are interconnected.
5. The repellent surface of claim 4 , wherein the surface features containing re-entrant curvature are mechanically robust to withstand damage from stresses encountered during use.
6. The repellent surface of claim 1 , wherein the surface features containing re-entrant curvature comprise interconnected pores.
7. The repellent surface of claim 1 , wherein the repellent surface is optically transparent.
8. The repellent surface of claim 1 , wherein the surface features containing re-entrant curvature are bound to the substrate.
9. The repellent surface of claim 1 , wherein surface features containing re-entrant curvature are obtained by an inverse structure of a monolayer of sacrificial colloidal particles.
10. The repellent surface of claim 9 , wherein the colloidal particles are substantially the same size.
11. The repellent surface of claim 9 , wherein the colloidal particles range in size from about 50 nm to more than tens of microns.
12. The repellent surface of claim 1 , wherein the substrate includes one or more curvatures.
13. A method of making a repellent surface of claim 1 , comprising:
forming a substrate having a plurality of surface features containing re-entrant curvature, wherein the surface feature containing re-entrant curvature have an opening diameter that is smaller than the interior pore diameter measured at the center of the pore; and
providing a lubricating liquid layer stably immobilized over said substrate having a plurality of surface features containing reentrant curvature.
14. The method of claim 13 , wherein the surface features containing re-entrant curvature have a pore opening angle that is between 0 and 90°.
15. The method of claim 13 , wherein the surface features containing re-entrant curvature have a pore opening angle that is between 45 and 80°.
16. The method of claim 13 , wherein the surface features containing re-entrant curvature are interconnected.
17. The method of claim 16 , wherein the surface features containing re-entrant curvature are mechanically robust.
18. The method of claim 13 , wherein the surface features containing re-entrant curvature contain interconnected pores.
19. The method of claim 13 , wherein the repellent surface is optically transparent.
20. The method of claim 13 , wherein the surface features containing re-entrant curvature are bound to the substrate.
21. The method of claim 13 , wherein said forming a substrate having a plurality of surface features containing re-entrant curvature comprises:
forming a monolayer of colloidal particles over the substrate;
filling the interstitial spaces between the colloidal particles of the monolayer to have a pore opening angle that is between 0 and 90°; and
removing the monolayer of colloidal particles to obtain surface features containing re-entrant curvature.
22. The method of claim 21 , wherein the colloidal particles are substantially the same size.
23. The method of claim 21 , wherein the colloidal particles range in size from about 50 nm to about tens of microns.
24. The method of claim 21 , further comprising:
patterning regions of said surface features containing re-entrant curvature with chemical groups that repel said lubricating liquid.
25. The method of claim 21 , further comprising:
patterning regions of said surface features containing re-entrant curvature with chemical groups that attract said lubricating liquid.
26. The repellent surface of claim 1 , wherein the plurality of surface features containing re-entrant curvature are effective to substantially stably immobilize the lubricating liquid between, on and over said substrate having a plurality of surface features containing re-entrant curvature, without dewetting from the substrate under atmospheric pressure, to form a repellant surface.