Friction reducing polyelectrolyte coating
A low friction coated article includes a first structure that has a first lubricated surface coated with a first polyelectrolyte coating. A second structure has a second lubricated surface with a second polyelectrolyte coating opposite the first lubricated surface. The first and second polyelectrolyte coatings include alternating layers of positively charged polyelectrolyte layers and negatively charged polyelectrolyte layers hydrated with a lubricant.
1. A low friction coated article comprising:
a first structure having a first lubricated surface coated with a first polyelectrolyte coating; and
a second structure having a second lubricated surface with a second polyelectrolyte coating opposite the first lubricated surface;
wherein the first and second polyelectrolyte coatings including alternating layers of positively charged polyelectrolyte layers and negatively charged polyelectrolyte layers both dehydrated from a liquid including water and hydrated with an oil based lubricant.
2. The low friction coated article of claim 1 , wherein the first and second polyelectrolyte coatings include one of the positively charged polyelectrolyte layers adjacent each of the first and second lubricated surfaces.
3. The low friction coated article of claim 2 , wherein the first and second polyelectrolyte coatings include N number of the positively charged polyelectrolyte layers and N−1 number of the negatively charged polyelectrolyte layers.
4. The low friction coated article of claim 3 , wherein N equals 6.
5. The low friction coated article of claim 2 , wherein an outer most layer of the first and second polyelectrolyte coatings includes one of the positively charged polyelectrolyte layers.
6. The low friction coated article of claim 1 , wherein at least one of the first and second polyelectrolyte coatings are macroscopically filled with lubricant.
7. The low friction coated article of claim 1 , wherein a coefficient of friction between the first coating and the second coating is less than 0.01, the positively charged polyelectrolyte layers include layers of a PEI material, and the negatively charged polyelectrolyte layers include layers of a PAA material.
8. The low friction coated article of claim 1 , wherein a coefficient of friction between the first coating and the second coating is less than 0.001, the positively charged polyelectrolyte layers include layers of a PEI material, and the negatively charged polyelectrolyte layers include layers of a PAA material.
9. The low friction coated article of claim 1 , wherein the positively charged polyelectrolyte layers include layers of a PEI material.
10. The low friction coated article of claim 1 , wherein the negatively charged polyelectrolyte layers include layers of a PAA material.
11. The low friction coated article of claim 1 , wherein the low friction coated article includes one of a journal bearing, a ball bearing, or a roller bearing.
12. A method of coating an article with a low friction coating, the method comprising:
applying a polyelectrolyte coating to a lubricated surface on a structure, wherein the polyelectrolyte coating includes at least one positively charged polyelectrolyte layer adjacent at least one negatively charged polyelectrolyte layer;
dehydrating a liquid including water from the polyelectrolyte coating; and
filling the polyelectrolyte coating dehydrated from the liquid with an oil based lubricant.
13. The method of claim 12 , wherein the at least one positively charged polyelectrolyte layer includes a plurality of positively charged polyelectrolyte layers and the at least one negatively charged polyelectrolyte layer includes a plurality of negatively charged polyelectrolyte layers and applying the polyelectrolyte coating includes applying the plurality of positive polyelectrolyte layers in an alternating pattern with the plurality of negatively charged polyelectrolyte layers.
14. The method of claim 13 , wherein the polyelectrolyte coating includes N number of the positively charged polyelectrolyte layers and N−1 number of the negatively charged layers and one of the plurality of positively charged polyelectrolyte layers is located directly adjacent the lubricated surface on the structure.
15. The method of claim 14 , wherein N equals 6.
16. The method of claim 13 , wherein an outer most layer of the polyelectrolyte coating includes one of the plurality of positively charged polyelectrolyte layers.
17. The method of claim 16 , wherein the plurality of positively charged polyelectrolyte layers and the plurality of negatively charged polyelectrolyte layers repel each other upon the application of a contact force to the polyelectrolyte coating.
18. The method of claim 13 , wherein applying the polyelectrolyte coating includes attaching at least one of water, ionic liquid, or liquid salt molecules to the plurality of positively charged polyelectrolyte layers and the plurality of negatively charged polyelectrolyte layers.
19. The method of claim 13 , wherein the plurality of positively charged polyelectrolyte layers include a PEI material and the plurality of negatively charged polyelectrolyte layers include a PAA material.
20. The method of claim 12 , wherein the article includes one of a journal bearing, a ball bearing, or a roller bearing.