Nanoparticle coatings and methods of making
A surface can be treated to deposit a superhydrophilic coating on a surface that can be antireflective and antifogging. The coating can remain antireflective and antifogging for extended periods. The coating can include oppositely charge inorganic nanoparticles, and can be substantially free of an organic polymer. The coating can be made mechanically robust by a hydrothermal calcination.
1. A method of treating a surface comprising:
depositing a first plurality of inorganic nanoparticles having a first electrostatic charge on a substrate;
depositing an oppositely charged polyelectrolyte over the first plurality of inorganic nanoparticles; and
contacting the first plurality of inorganic nanoparticles and the oppositely charged polyelectrolyte at a calcination temperature less than 500° C. with a calcination reagent selected to promote fusing of nanoparticles and polyelectrolytes at a calcination temperature less than 500° C.
2. The method of claim 1 , wherein the oppositely charged polyelectrolyte includes a second plurality of inorganic nanoparticles.
3. The method of claim 2 , wherein the first plurality of inorganic nanoparticles has a different average particle size than the second plurality of inorganic nanoparticles.
4. The method of claim 2 , wherein the first plurality of inorganic nanoparticles includes a plurality of silicon dioxide nanoparticles.
5. The method of claim 4 , wherein the second plurality of inorganic nanoparticles includes a plurality of titanium dioxide nanoparticles.
6. The method of claim 1 , wherein the calcination temperature is less than 200° C.
7. The method of claim 1 , wherein the calcination temperature is less than 150° C.
8. The method of claim 7 , wherein the calcination reagent is water.
9. The method of claim 7 , contacting the first plurality of inorganic nanoparticles and the oppositely charged polyelectrolyte with a calcination reagent at a calcination temperature includes contacting at a calcination pressure.
10. The method of claim 1 , wherein the calcination pressure is in the range of 10 psi to 30 psi.
11. The method of claim 1 , further comprising repeating the steps of depositing a first plurality of inorganic nanoparticles having a first electrostatic charge on a substrate and depositing an oppositely charged polyelectrolyte over the first plurality of inorganic nanoparticles; thereby forming an electrostatic multilayer.
12. The method of claim 11 , wherein the electrostatic multilayer is substantially free of an organic polymer.
13. The method of claim 8 , wherein water is selected to facilitate a hydrolysis reaction.