Coatings
A superhydrophilic coating can be antireflective and antifogging. The coating can remain antireflective and antifogging for extended periods. The coating can have a graded refractive index. The coating for wafer-level optics can be for targeted capillary condensation in nanoparticle containing reflow-compatible coatings.
1. A surface comprising a nanoporous coating including a first thickness including a first plurality of nanoparticles having a first diameter and having a first porosity and a second thickness including a second plurality of nanoparticles having a second diameter different from the first diameter and having a second porosity different from the first porosity, the coating including:
a first functionalizing compound present in the first porosity as a capillary condensate,
a second functionalizing compound present in the second porosity as a capillary condensate,
wherein the first and second functional compounds are different, wherein the coating has a thickness of less than 500 nm wherein the first functionalizing compound is a polymer or a polymer precursor capable of forming a capillary condensate in capillary interstices, and wherein pores in the first thickness are formed between the first plurality of nanoparticles and pores in the second thickness are formed between the second plurality of nanoparticles.
2. The surface of claim 1 , wherein the coating has a thickness of less than 300 nm.
3. The surface of claim 1 , wherein the surface is transparent.
4. The surface of claim 1 , wherein the first functionalizing compound is substantially absent from the second porosity.
5. A surface comprising a nanoporous coating including a preselected porosity and a preselected first functionalizing compound and a preselected second functionalizing compound, the first and second functionalizing compounds being capillary-condensed within the porosity, wherein the nanoporous coating includes a plurality of inorganic nanoparticles having capillary interstices among the nanoparticles and the coating has a thickness of less than 500 nm, wherein the first functionalizing compound is a polymer or a polymer precursor capable of forming a capillary condensate in capillary interstices, wherein the second functionalizing compound is a polymer or a polymer precursor capable of forming a capillary condensate in capillary interstices, and wherein the first and second functional compounds are different.