Surface treatment of fluorinated contact lens materials
View Patent ↗Hydrogen-plasma modification of a contact lens made from a fluorinated polymer reduces the surface chemistry of by removing fluorine, leaving behind a carbon-enriched surface that is further plasma processed into a hydrophilic surface for a lens material to be inserted into the ocular environment.
1. A fluorinated contact lens containing a fluorinated bulk material and a surface coating which, when the lens is in the unhydrated state, is characterized by a fluorine content or a C—F bonding content within a depth of about 74 ångstroms that is at least 25 percent depleted relative to the bulk material, and which contact lens is further characterized by hydrophilic polymers attached to the surface of the contact lens through oxygen or nitrogen containing moieties to provide the contact lens with improved wettability or biocompatibility.
2. The fluorinated contact lens of claim 1 wherein the surface coating is an optically clear hydrophilic surface film.
3. The fluorinated contact lens of claim 1 wherein the lens is made from fluorinated polymer materials selected from the group consisting of hydrogel and non-hydrogel materials.
4. The fluorinated contact lens of claim 1 wherein the lens is capable of extended wear for continuous periods of at least 24 hours.
5. The fluorinated contact lens of claim 4 wherein the lens is capable of continuous wear for at least 3 days.
6. The fluorinated contact lens of claim 4 wherein the lens is capable of continuous wear for at least 30 days.
7. The contact lens and surface coating of claim 1 which, when in the unhydrated state, is characterized by a fluorine or C—F bonding content within a depth of about 74 ångstroms that is at least 50 percent depleted relative to the bulk material.
8. The contact lens of claim 1 wherein the fluorinated bulk material comprises 5 to 15 mole percent fluorine atoms based on the amounts and structural formula of the components in bulk of the fluorinated polymer making up the contact lens.
9. The contact lens of claim 3 wherein the fluorinated non-hydrogel material comprises at least about 10 mole percent fluorine atoms, based on the amounts and structural formulae of the components of the polymer.
10. The contact lens of claim 9 wherein the fluorinated non-hydrogel material comprises about 20 to about 70 mole percent fluorine based on the amounts and structural formulae of the components of the polymer.
11. The contact lens of claim 9 wherein the fluorinated non-hydrogel material comprises perfluorinated monomers.
12. The contact lens of claim 11 wherein the perfluorinated monomers comprise an amorphous copolymer of perfluoro-2,2-dimethyl-1,3-dioxole with one or more copolymerizably acceptable ethylenically unsaturated fluorinated comonomers, the proportion of perfluoro-2,2-dimethyl-1-3 dioxole in the copolymer being at least about 20 mole percent of the copolymer.
13. The contact lens of claim 12 wherein the contact lens material further comprises from 10 to 80 weight percent of one or more other comonomers selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene (CTFE) vinylidene fluoride, perfluoro (alkyl vinyl) ether (PAVE) having the formula
CF 2 —CFO(CF 2 CFXO) n R f
wherein X is F or CF 3 , n is 0–5, and R f is a perfluoroalkyl group of 1–6 carbon atoms, and mixtures thereof.