Robust superhydrophobic material and coating
The invention provides a composition for forming a hydrophobic material, the composition being made by combining: a perfluorinated amine compound comprising at least two amine moieties, such as a compound made by combining a straight or branched chain C 1-10 alkyl amine having at least two amine groups per molecule, with a straight or branched chain C 1-12 perfluorinated carboxylic acid confining at least one —COOH group per molecule; an epoxy compound comprising at least two epoxy moieties; a lubricant, such as a perfluorinated polyether; a population of nanoparticles; and a solvent. Hydrophobic materials formed by evaporation of the solvent from such a composition are also provided as are intermediates excluding the lubricant which are used in the formation of such compositions. Such compositions are used in the formation of hydrophobic and particularly superhydrophobic surfaces. Advantageously these compositions are useful to form robust surface coatings that are resistant to mechanical wear.
1 . A composition for forming a hydrophobic material, the composition made by combining:
a fluorinated amine compound comprising at least two amine moieties;
an epoxy compound comprising at least two epoxy moieties;
a lubricant which is a perfluorinated polyether or a silicone oil;
a population of nanoparticles; and
a solvent.
2 . A composition according to claim 1 , wherein the epoxy compound is selected from bisphenol di- or poly-glycidyl ether compounds.
3 . A composition according to claim 2 , wherein the epoxy compound is selected from bisphenol-A, bisphenol-AP, bisphenol-B, bisphenol-BP, bisphenol-C, bisphenol-E, bisphenol-F, bisphenol-G, bisphenol-M, bisphenol-P, or bisphenol-PH.
4 . A composition according to claim 1 , wherein the fluorinated amine compound is made by combining a straight or branched chain C 1-10 alkyl amine having at least two amine groups per molecule, with a straight or branched chain C 1-12 fully or partially fluorinated carboxylic acid containing at least one —COOH group per molecule.
5 . A composition according to claim 4 , wherein the fluorinated amine compound is made by combining an amine selected from diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and ethylenediamine; with a carboxylic acid selected from trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, heptafluoroisobutyric acid, nonafluorovaleric acid, nonafluoroisovaleric acid, nonafluoropivalic acid, difluoroacetic acid, 3,3,3-trifluoropropionic acid, 3,3,3-trifluoromethyl-2-trifluoromethylpropionic acid, (R,S)-5,7-difluorotryptophan hydrochloride, (R,S)-5,6,7-trifluorotryptophan hydrochloride, 2-amino-3-(4,5,6,7-tetrafluoro-1H-indol-3-yl) propionic acid hydrochloride, and (R,S)-4,5,6,7-tetrafluorotryptophan hydrochloride.
6 . A composition according to claim 4 , wherein the amine and the fully or partially fluorinated carboxylic acid are combined to form the fluorinated amine compound in an amine:carboxylic acid molar ratio in the range 1:0.75-1:2.
7 . A composition according to claim 1 , wherein the lubricant is a perfluorinated polyether.
8 . A composition according to claim 7 , wherein the perfluorinated polyether is a fluorocarbon ether polymer of polyhexafluoropropylene oxide having a chemical formula II:
F—(CF(CF 3 )—CF 2 —O) n —CF 2 CF 3 (II),
wherein n is in the range 10 to 60.
9 . A composition according to claim 1 , wherein the nanoparticles in the population of nanoparticles are formed from material selected from TiO 2 , SiO 2 , ZnO, MnO, PTFE, CeO 2 , graphene, graphene oxide, carbon nanotubes, and carbon black.
10 . A composition according to claim 1 , wherein the amount of nanoparticles included in the composition is below about 80 wt. % of the composition excluding solvent.
11 . A hydrophobic material formed by evaporation of solvent from a composition according to claim 1 , the hydrophobic material comprising:
a cured fluorinated epoxy resin;
the lubricant; and
the population of nanoparticles.
12 . An intermediate for forming a composition according to claim 1 , wherein the intermediate is made by combining:
the epoxy compound comprising at least two epoxy moieties;
the fluorinated polyether;
the population of nanoparticles; and
the solvent.
13 . A kit comprising an intermediate according to claim 12 , and a fluorinated amine compound comprising at least two amine moieties.
14 . An article made from or coated with a composition according to claim 1 or a hydrophobic material formed by evaporation of solvent from a composition according to claim 1 , the hydrophobic material comprising:
a cured fluorinated epoxy resin;
the lubricant; and
the population of nanoparticles.
15 . A method of applying a hydrophobic coating to an article, the method comprising applying a composition according to claim 1 to the surface of the article, and heating the article and coating in air at between 8° and 120° C.