Patent Publication Number: US-7582704-B2

Title: Biomedical devices

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention generally relates to biomedical devices, and especially ophthalmic lenses that are intended for direct placement on or in the eye such as contact lenses or intraocular lenses, where the devices and lenses are formed from a network of a crosslinked trifluorovinyl containing polymers. 
     2. Description of Related Art 
     In the field of biomedical devices such as contact lenses, various factors must be considered in order to yield a material that has appropriate characteristics. For example, various physical and chemical properties such as oxygen permeability, wettability, material strength and stability are but a few of the factors that must be carefully balanced to provide a useable contact lens. Since the cornea receives its oxygen supply exclusively from contact with the atmosphere, good oxygen permeability is a critical characteristic for any contact lens material. Wettability is also important in that, if the lens is not sufficiently wettable, it does not remain lubricated and therefore cannot be worn comfortably in the eye. Accordingly, the optimum contact lens would have at least both excellent oxygen permeability and excellent tear fluid wettability. 
     Contact lenses made from fluorinated materials have been investigated for a number of years. Such materials can generally be subdivided into two major classes, namely hydrogels and non-hydrogels. Hydrogels can absorb and retain water in an equilibrium state whereas non-hydrogels do not absorb appreciable amounts of water. Regardless of their water content, both hydrogel and non-hydrogel fluorinated contact lenses tend to have relatively hydrophobic, non-wettable surfaces. 
     By introducing fluorine-containing groups into contact lens polymers, the oxygen permeability can be significantly increased. For example, U.S. Pat. No. 4,996,275 discloses using a mixture of comonomers including the fluorinated compound bis(1,1,1,3,3,3-hexafluoro-2-propyl)itaconate in combination with organosiloxane components. Fluorinating certain polysiloxane materials has been indicated to reduce the accumulation of deposits on contact lenses made from such materials. See, for example, U.S. Pat. Nos. 4,440,918; 4,954,587; 4,990,582; 5,010,141 and 5,079,319. However, fluorinated polymers can suffer from one or more of the following drawbacks: difficult and/or expensive synthetic routes, poor processability, low refractive index, poor wettability, poor optical clarity, poor miscibility with other monomers/reagents and toxicity. 
     The thermal polymerization products of trifluorovinyl-containing monomers, e.g., bis-trifluorovinyl monomers, to form perfluorocyclobutylene polymers are known. See, e.g., U.S. Pat. Nos. 5,021,602; 5,023,380; 5,037,917; 5,037,918; 5,037,919; 5,066,746; 5,159,036; 5,159,037; 5,159,038, 5,162,468; 5,198,513; 5,210,265; 5,246,782; 5,364,547; 5,364,917 and 5,409,777. U.S. Pat. Nos. 5,037,918; 5,066,746; 5,159,036; 5,159,037 and 5,246,782 further disclose the use of a “crosslinking initiating means” on perfluorocyclobutane polymers, subsequent to a completed step of polymerization, to obtain crosslinked polymers. Additionally, U.S. Pat. Nos. 5,246,782 and 5,409,777 disclose that the polymers are useful as, for example, passivation coatings on medical instruments and in packaging for medical devices such as bandages and operating equipment. However, there has been no recognition or appreciation that such materials can be employed in the manufacture of biomedical devices and particularly contact lens applications. 
     Accordingly, it would be desirable to provide improved biomedical devices formed from crosslinked fluorinated polymerization products biomedical devices that exhibit suitable physical properties, e.g., modulus and tear strength, and chemical properties, e.g., oxygen permeability and wettability, for prolonged contact with the body while also being biocompatible. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, a biomedical device is provided which is formed from a network of a polymer comprising perfluoroaliphatic groups in the polymer backbone wherein the network is formed by crosslinks in the polymer. 
     In accordance with a second embodiment of the present invention, a biomedical device is provided which is formed from a network of a polymer comprising one or more perfluorocyclobutane groups in the polymer backbone wherein the network is formed by crosslinks in the polymer. 
     In accordance with a third embodiment of the present invention, a biomedical device is provided which is formed from a polymerization product of a monomeric mixture comprising one or more monomers comprising two or more reactive trifluorovinyl groups. 
     In accordance with a fourth embodiment of the present invention, a biomedical device is provided which is formed from a polymerization product of a monomeric mixture comprising one or more monomers comprising three or more reactive trifluorovinyl groups. 
     In accordance with a fifth embodiment of the present invention, a biomedical device is provided comprising a polymerization product of a monomeric mixture comprising a first monomer comprising a polysiloxane prepolymer having one or more trifluorovinyl groups and a second crosslinking monomer comprising three or more reactive trifluorovinyl groups. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The figures set forth herein illustrate various embodiments of the present invention wherein: 
         FIG. 1  is a polysiloxane containing star monomer which can be employed in the manufacture of a biomedical device of the present invention; 
         FIG. 2  is a polysiloxane containing cyclic monomer which can be employed in the manufacture of a biomedical device of the present invention; 
         FIG. 3  is a polysiloxane containing polycyclic monomer which can be employed in the manufacture of a biomedical device of the present invention. 
         FIG. 4  illustrates a contact angle (θ) shown for the left side of the drop for measuring the Static Contact Angle (SCA) of Examples 6-8; and 
         FIG. 5  illustrates the general reaction scheme of Example 9. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is directed to biomedical devices intended for direct contact with body tissue or fluid. Representative examples of biomedical devices include, but are not limited to, artificial ureters, diaphragms, intrauterine devices, heart valves, catheters, denture liners, prosthetic devices, ophthalmic lens applications, where the lens is intended for direct placement in or on the eye, such as, for example, intraocular devices and contact lenses. A wide variety of types of contact lens materials can be produced herein ranging from hard, gas permeable lens materials; soft, hydrogel lens materials to soft, non-hydrogel lens materials. A particularly preferred contact lens is a rigid gas permeable lens. 
     The biomedical devices of the present invention can advantageously be formed from a network of a perfluoro containing polymer wherein the network is formed by crosslinks in the polymer. For example, the biomedical devices of the present invention can be formed from a network of a crosslinked polymer obtained from a polymerization product of a monomeric mixture including at least one or more monomers having two or more reactive trifluorovinyl groups. In the practice of this invention, the polymers are crosslinked which involves chemical reactions that interconnect polymer molecules. As these reactions proceed, a polymer network is formed. 
     Suitable crosslinking monomers in forming the network of crosslinked polymers or copolymers of the biomedical devices of the present invention include, but are not limited to, crosslinking monomers having two or more reactive trifluorovinyl groups, crosslinking monomers having two or more reactive trifluorovinyl ether groups, crosslinking monomers having two or more reactive trifluorovinyl aromatic ether groups, and the like and mixtures thereof. 
     In one embodiment, a biomedical device of the present invention can be formed from a network of a polymer comprising perfluoroaliphatic groups in the polymer backbone wherein the network is formed by crosslinks in the polymer. Such polymers can be obtained from the polymerization product of at least a monomeric mixture containing at least one or more monomers having at least two trifluorovinyl groups. For example, the crosslinked polymers can be obtained from at least a monomeric mixture containing at least one or more trifluorovinyl containing monomers represented by the general formula I:
 
F 2 C═CF—X—R 1 —(X—CF═CF 2 ) z   (I)
 
wherein R 1  represents one or more inertly substituted groups; X is independently a group which links the inertly substituted groups and the trifluorovinyl group and z is from 1 to about 1000, preferably from 1 to about 100, more preferably from 1 to about 10 and most preferably from 1 to about 5. As one skilled in the art would readily appreciate, the trifluorovinyl containing moiety can be present as one or more pendant groups in the monomer, e.g., in the case where R 1  is an alkylene group such as ethylene or in the case where R 1  is a polycyclic group, as well as an end group(s). The X groups can be the same or different and include, but are not limited to, a bond, an oxygen atom, a sulfur atom, a carboxylic or thiocarboxylic ester group, an amide group, a sulfone, a sulfoxide, a carbonate, a carbamate, a perfluoroalkylene, a perfluoroalkylene ether, an alkylene, an acetylene, a phosphine, a carbonyl or thio carbonyl group, seleno, telluro, nitrido, a silanediyl group, a trisilanediyl group, a tetrasilanetetrayl group, a siloxanediyl group, a disiloxanediyl group, a trisiloxyldiyl group, a trisilazanyl group, a silythio group, a boranediyl group; and the like and combinations thereof. By “inert” it is meant that the structures or substituents do not react undesirably with the perfluorovinyl groups or interfere undesirably with polymerization (e.g., perfluorocyclobutane formation) of the monomers.
 
     Representative R 1  groups include, by way of example, a substituted or unsubstituted C 1  to C 30  hydrocarbyl group such as a substituted or unsubstituted C 1  to about C 30  and preferably a substituted or unsubstituted C 1  to about C 16  alkyl or an aromatic group optionally containing one or more heteroatoms; or a C 3  to about C 25  cycloalkyl groups optionally containing one or more heteroatoms, substituted or unsubstituted siloxanyl group, or combinations thereof. In one embodiment, R 1  comprises one or more substituted or unsubstituted cyclic or polycyclic containing groups, e.g., one or more substituted or unsubstituted aromatic groups optionally containing one or more heteroatoms, and wherein each X group is bonded to the cyclic group in a position either ortho, meta, and/or para with respect to one another. Suitable aromatic group(s) can be of any molecular structure having aromatic character such as at least one six membered aromatic ring, optionally having any number of such six-membered rings fused together or connected by bonds or linking structures. For example, the aromatic groups can have from 1 to about 50 such substituted or unsubstituted aromatic rings, and preferably from 1 to about 10 substituted or unsubstituted aromatic rings. If desired, when more than one cyclic containing group such as the aromatic groups are employed, the cyclic containing groups can be linked together with the same or different linking group, e.g., a C 1 -C 20  alkylene or haloalkylene group optionally containing ether or ester linkages. 
     Examples of aromatic groups for use herein include, but are not limited to, the following structures: 
                         
wherein R is independently hydrogen, a C 1 -C 20  alkyl group, a hydroxyl group, a C 1 -C 20  carboxylic acid group, a C 1 -C 20  ester group, a C 1 -C 20  alkoxy group, CO 2   − , CO 2   − , SO 3   − , PO 3   − , OPO 3   2− , F, Br, I, NA 2  or NA 3   +  wherein A is independently hydrogen, a C 1 -C 20  alkyl group, a hydroxyl group, a C 1 -C 20  carboxylic acid group, a C 1 -C 20  ester group, or a C 1 -C 20  alkoxy group, or two R groups together with the carbon atom to which they are bonded are joined together to form a cyclic structure optionally containing one or more heterocyclic groups; R 2  is a bond, a C 1 -C 20  alkylene or haloalkylene group optionally containing ether or ester linkages and wherein each X group may independently be bonded to the aromatic group either ortho, meta and/or para with respect one another. Representative examples of such aromatic groups include, but are not limited to,
 
                         
Although the aromatic groups of R 1  are shown as being bonded in the para position, all positions on the aromatic ring are contemplated herein, e.g., ortho, meta, para and combinations thereof. In another embodiment, R 1  comprises one or more substituted or unsubstituted cyclic or polycyclic siloxane containing groups.
 
     In an alternative embodiment, the crosslinked polymers can be obtained from at least a monomeric mixture containing at least one or more trifluorovinyl containing monomers represented by the general formula II: 
                         
wherein R 3  is independently hydrogen, a substituted or unsubstituted C 1 -C 30  alkyl, a substituted or unsubstituted C 1 -C 30  alkoxy, a substituted or unsubstituted C 3 -C 30  cycloalkyl, a substituted or unsubstituted C 3 -C 30  cycloalkylalkyl, a substituted or unsubstituted C 3 -C 30  cycloalkenyl, a substituted or unsubstituted C 5 -C 30  aryl, a substituted or unsubstituted a C 5 -C 30  arylalkyl, a substituted or unsubstituted C 5 -C 30  heteroaryl, a substituted or unsubstituted C 3 -C 30  heterocyclic ring, a substituted or unsubstituted C 4 -C 30  heterocyclylalkyl, or a substituted or unsubstituted C 6 -C 30  heteroarylalkyl; X′ has the aforestated meanings for X; a is from 2 to about 100 and preferably from 2 to about 10; and T is the same or different and is of the general formula:
 
                         
wherein R 4  independently represents one or more inertly substituted groups as defined above for R 1 ; X has the aforestated meanings and is independently a group which links the inertly substituted groups and the trifluorovinyl group and L is an optional linking group and is independently a straight or branched C 1 -C 30  alkyl group, a C 3 -to C 30  cycloalkyl group, a C 5 -C 30  aryl group, an ether group, a C 1 -C 20  ester group, an amide group, a siloxanyl, an arylsiloxanyl or a fluorosiloxanyl. In the case where R 4  is a cyclic or polycyclic group, the X group and either the L group or Si atom may independently be bonded to the cyclic group either ortho, meta and/or para with respect to one another. Specific examples of the foregoing trifluorovinyl containing monomers of formula II are set forth in  FIGS. 1-3 .
 
     In another embodiment, the crosslinked polymers can be obtained from at least a monomeric mixture containing at least one or more C 1 -C 20  tris(trifluorovinyloxyaryl)alkanes such as 1,1,1-tris(4′-[trifluorovinyloxy]phenyl)ethane. 
     The foregoing trifluorovinyl containing monomers are either commercially available from such sources as, for example, Tetramer Technologies through Oakwood Products (West Columbia, S.C.), or can be prepared by any method known in the art which links molecular structures having perfluorovinyl groups to other molecular structures or which form perfluorovinyl groups and does not constitute a part of the present invention. See, e.g., U.S. Pat. No. 5,023,380, the contents of which are incorporated by reference herein. 
     The foregoing monomeric mixtures containing at least the trifluorovinyl containing monomers may be polymerized by free radical polymerization by exposing the mixture to heat and/or radiation, e.g., ultraviolet light (UV), visible light, or high energy radiation, to produce biomedical devices such as contact lenses according to conventional methods. A polymerization initiator may be included in the mixture to facilitate the polymerization step. Representative free radical thermal polymerization initiators are organic peroxides such as, for example, acetal peroxide, lauroyl peroxide, decanoyl peroxide, stearoyl peroxide, benzoyl peroxide, tertiarylbutyl peroxypivalate, peroxydicarbonate, and the like and mixtures thereof. Representative UV initiators are those known in the field such as, for example, benzoin methyl ether, benzoin ethyl ether, Darocure 1173, 1164, 2273, 1116, 2959, 3331 (EM Industries) and Igracure 651 and 184 (Ciba-Geigy), and the like and mixtures thereof. Generally, the initiator will be employed in the monomeric mixture at a concentration at about 0.1 to about 5 percent by weight of the total mixture. 
     When producing crosslinked polymers and copolymers from the free radical polymerization process, the crosslinked polymers and copolymers will ordinarily have repeating units of the general formula: 
                         
As one skilled in the art will readily appreciate, the number of repeating perfluoroaliphatic groups can vary from as few as one up to thousands. For the trifluorovinyl containing monomers of formula I wherein z is 1 to 6 or more, the crosslinked polymers and copolymers produced from the free radical polymerization method will result in a highly crosslinked polymer system. Additionally, substantially similar repeating units will form when polymerizing the monomers represented in formula II.
 
     In another embodiment of the present invention, the crosslinked polymers can be obtained from at least a monomeric mixture containing at least one or more trifluorovinyl containing monomers having at least three dimerizable perfluorovinyl groups. A dimerizable perfluorovinyl group is a perfluorovinyl group which reacts with another such group to form one or more perfluorocyclobutane rings represented by the general formula: 
                         
Thus, the resulting polymers will have one or more perfluorocyclobutane groups, and includes oligomers which have from about 2 to about 100 repeating units. The molecular weight of the resulting polymers can vary widely, e.g., a number average molecular weight of at least about 100 and can range from about 100 to about 1,000,000. It is to be understood that depending on the molecular structure connecting the perfluorocyclobutane groups, the number of perfluorocyclobutane groups can vary from as few as one up to thousands. The process of forming polymers or oligomers herein is general and capable of forming biomedical devices having wide ranges of utility. The physical and chemical properties of the resulting products are highly dependent on the choice of the molecular structure between the perfluorocyclobutane groups as well as the number of perfluorocyclobutane groups.
 
     Any monomer having at least three dimerizable perfluorovinyl groups can be used herein to form the crosslinked polymers. Whereas polyaddition of perfluorovinyl groups to form perfluoroaliphatic polymers (e.g., poly(tetrafluoroethylene)), not generally having perfluorocyclobutane groups, takes place in the presence of free radicals or free radical generating catalysts, dimerization to form perfluorocyclobutane groups takes place thermally. 
     When a perfluorovinyl group is dimerizable, dimerization is preferably favored over other thermal reactions either kinetically or in equilibrium. As one skilled in the art would readily appreciate, the perfluorovinyl groups on a monomer can be separated by at least one atom or group of atoms which does not facilitate isomerization. The atom or group of atoms can include at least one aromatic group or can include an aliphatic or cycloalkyl group. However, aromatic groups are usually preferred due their ease of manufacturing monomers. Furthermore, when the perfluorovinyl groups are attached to aliphatic carbons or separated from aliphatic carbons by single atoms such as, for example, oxygen, the perfluorovinyl groups are preferably primary or secondary because tertiary perfluorovinyl groups are generally sterically hindered with respect to formation of perfluorocyclobutane rings, and more preferably the perfluorovinyl groups are primary because secondary perfluorovinyl groups tend to rearrange. Preferably, to avoid rearrangement and facilitate polymer formation the monomers have structures such that the resulting polymers have hydrocarbyl groups, e.g., one or more substituted or unsubstituted aromatic rings, perfluorocyclobutane rings and at least one non-carbon atom, e.g., oxygen, silicon, boron, phosphorus, nitrogen, selenium, tellurium and/or sulfur atom (each optionally substituted) in the backbones. 
     In one embodiment, the crosslinked polymers can be obtained from at least a monomeric mixture containing at least one or more monomers having at least three dimerizable perfluorovinyl groups represented by the general formula III:
 
F 2 C═CF—X—R 5 —(X—CF═CF 2 ) m   (III)
 
wherein R 5  represents one or more inertly substituted groups as defined above for R 1 ; X independently is a group which links the inertly substituted groups and the trifluorovinyl group and has the aforestated meanings and m is an integer of 2 to about 1000, preferably from 2 to about 100, more preferably from 2 to about 10 and most preferably from 2 to about 5. Representative examples of R 5  include, but are not limited to, aromatic groups of the general formula:
 
                         
wherein R is independently hydrogen, a C 1 -C 20  alkyl group, a hydroxyl group, a C 1 -C 20  carboxylic acid group, a C 1 -C 20  ester group, a C 1 -C 20  alkoxy group, CO 2   − , SO 3   − , PO 3   − , OPO 3   2− , F, Br, I, NA 2  or NA 3   +  wherein A is independently hydrogen, a C 1 -C 20  alkyl group, a hydroxyl group, a C 1 -C 20  carboxylic acid group, a C 1 -C 20  ester group, or a C 1 -C 20  alkoxy group, or two R groups together with the carbon atom to which they are bonded are joined together to form a cyclic structure optionally containing one or more heterocyclic groups; R 2  is a bond, a C 1 -C 20  alkylene or haloalkylene group optionally containing ether or ester linkages and m is from 1 to about 10 and wherein each X group may independently be bonded to the aromatic group in any position. In an alternative embodiment, the monomeric mixture will include at least one or more trifluorovinyl containing monomers having at least three dimerizable perfluorovinyl groups as represented by the general formula II above, i.e., the case wherein a is from 3 to about 100 and preferably from 3 to about 10.
 
     The foregoing monomers having at least three dimerizable perfluorovinyl groups useful in the practice of the invention are commercially available from such sources as, for example, Tetramer Technologies through Oakwood Products (West Columbia, S.C.), or can be prepared by any method known in the art which links molecular structures having perfluorovinyl groups to other molecular structures or which form perfluorovinyl groups as discussed above and does not constitute a part of the present invention. 
     In another embodiment, the crosslinked polymers can be obtained from at least a monomeric mixture containing at least one or more trifluorovinyl containing monomers having at least three dimerizable perfluorovinyl groups represented by the general formula IV:
 
F 2 C═CF—X—R 6 —(X—CF═CF 2 ) m   (IV)
 
wherein X has the aforestated meaning and is independently a group which links the R 6  group and the trifluorovinyl group; R 6  is one or more substituted or unsubstituted C 3 -C 25  cycloalkyl groups optionally containing one or more heteroatoms and m is an integer of 2 to 5. Preferred cycloalkyl groups are of the formulae
 
     
       
         
         
             
             
         
       
     
     The crosslinked polymers formed from a monomeric mixture containing at least the monomers having at least three dimerizable perfluorovinyl groups can be polymerized by heating the monomeric mixture to a temperature and for a time sufficient to form a crosslinked polymer or copolymer having one or more perfluorocyclobutane rings in the backbone of the polymer. Suitable temperatures for forming one or more perfluorocyclobutane rings can differ according to the structure of the monomer. In general, temperatures can range from about 50° C. to about 400° C. and preferably from about 75° C. to about 300° C. for formation of perfluorocyclobutane rings. Temperatures above about 450° C. are usually avoided because perfluorocyclobutane groups are generally thermally unstable above such temperatures. In another embodiment, a temperature of from about 100° C. to about 230° C. is generally most preferred for cyclization of perfluorovinyl aromatic or aliphatic ethers or sulfides, while a temperature of from about 50° C. to 80° C. is needed to form perfluorocyclobutane groups when the perfluorovinyl group is attached directly to an aromatic ring. A suitable time can vary according to the temperature used and the structure of the monomer. Generally, the time period for the polymerization can range from about 1 hour to about 100 hours and preferably from about 10 hours to about 40 hours. 
     Alternatively, in the case when the trifluorovinyl containing monomers are capable of radical initiated addition polymerization, conditions conducive to free radical polymerization, e.g. presence of oxygen, ozone, peroxygen compounds and other free radical generating compounds, are avoided so that the trifluorovinyl groups will dimerize into perfluorocyclobutane groups rather than undergoing addition polymerization. Compounds known in the art for stabilization against free radical polymerization are alternatively used. Similarly, when the trifluorovinyl groups are capable of addition polymerization in the presence of anions or cations, compounds which supply such anions or cations are avoided. For example, fluoride ions (e.g. from carbonyl fluorides), chloride, hydroxide, phenoxide and the like are avoided. To avoid such compounds as carbonyl fluorides, oxidative conditions such as the presence of oxygen, hypochlorite, dichromate, permanganate and the like are avoided because the perfluorovinyl groups are known to oxidize to form carbonyl fluorides. Perfluorovinyl ethers, thioethers, sulfones, sulfoxides and the like are relatively stable with regard to addition polymerization and oxidation; and, therefore, such precautions are generally unnecessary when such perfluorovinyl compounds are used. 
     The monomeric mixtures are suitably neat or, optionally, in admixture with other materials such as in a solution, an emulsion, a dispersion or in any other form in which monomer molecules can be crosslinked to provide a crosslinked polymer. 
     Suitable solvents are those which are inert to the conditions encountered in the polymerization reaction and include, but are not limited to, xylene, mesitylene and perfluorotetradecahydrophenanthrene. At atmospheric pressure, preferred solvents are those which attain temperatures of about 170° C. to about 250° C. such as, for example, dichlorobenzene, trichlorobenzene, diphenyl oxide and perfluorotetradecahydrophenanthrene. When a solvent is used, the concentration of monomers in solvent is advantageously from about 0.1 to about 99.9 weight percent and preferably from about 10 to about 90 weight percent by weight monomer. 
     Polymerization and crosslinking while dimerizing suitably takes place at any pressure. Pressures are generally chosen such that the monomers and any solvents and/or dispersing media remain liquid at the temperatures used for polymerization. When the monomers or other materials evaporate at temperatures used, then it is generally preferable to maintain a pressure at least sufficient to maintain the materials liquid. 
     The foregoing monomeric mixtures containing the trifluorovinyl containing monomers, e.g., the monomers represented by formulae I-IV, can further contain one or more prepolymers. Suitable prepolymers include, but are not limited to, poly(siloxane) prepolymers, poly(alkyl ethers) prepolymers, poly(aromatic ether) prepolymers, poly(perfluorocyclobutane) prepolymers, copolymers thereof and the like and mixtures thereof. For example, the poly(siloxane) prepolymers can be represented by the general formula 
                         
wherein n and p are independently integers from 1 to about 1000, preferably 1 to about 100, more preferably from 1 to about 10 and most preferably from 1 to about 5; o is an integer from 1 to about 1000; R 7  independently represents one or more inertly substituted groups as defined above for R 1 ; X is independently a group which links the inertly substituted groups and the trifluorovinyl group; R 8  is independently an amide group, a C 1 -C 20  ester group, an ether group, an ureido, a substituted or unsubstituted C 3 -C 30  cyclicalkyl, or a C 1 -C 30  alkylene or haloalkylene group optionally containing ether or ester linkages; and R 9 , R 10 , R 11  and R 12  are independently hydrogen, a straight or branched C 1 -C 30  alkyl group, a C 1 -C 30  fluoroalkyl group, one or more substituted or unsubstituted aromatic groups, a C 1 -C 20  ester group, an ether group, an ureido group, an amide group, an amine group, a substituted or unsubstituted C 1 -C 30  alkoxy, a substituted or unsubstituted C 3 -C 30  cycloalkyl, a substituted or unsubstituted C 3 -C 30  cycloalkylalkyl, a substituted or unsubstituted C 3 -C 30  cycloalkenyl, a substituted or unsubstituted C 5 -C 30  aryl, a substituted or unsubstituted C 5 -C 30  arylalkyl, a substituted or unsubstituted C 5 -C 30  heteroaryl, a substituted or unsubstituted C 3 -C 30  heterocyclic ring, a substituted or unsubstituted C 4 -C 30  heterocyclylalkyl, a substituted or unsubstituted C 6 -C 30  heteroarylalkyl, fluorine, a vinyl group, a C 5 -C 30  fluoroaryl, or a hydroxyl.
 
     The biomedical devices of the present invention, e.g., contact lenses or intraocular lenses, can be prepared by polymerizing the foregoing monomeric mixtures to form a product that can be subsequently formed into the appropriate shape by, for example, lathing, injection molding, compression molding, cutting and the like Alternatively, the reaction mixture may be placed in a mold and subsequently cured into the appropriate product. 
     For example, in producing contact lenses, the initial monomeric mixture containing the foregoing trifluorovinyl containing monomers may be polymerized and crosslinked in tubes to provide rod-shaped articles, which are then cut into buttons. The buttons may then be lathed into contact lenses. Alternately, the contact lenses may be cast directly in molds from the monomeric mixtures, e.g., by spincasting and static casting methods. Spincasting methods are disclosed in U.S. Pat. Nos. 3,408,429 and 3,660,545, and static casting methods are disclosed in U.S. Pat. Nos. 4,113,224, 4,197,266, and 5,271,875. Spincasting methods involve charging the monomer mixture to a mold, and spinning the mold in a controlled manner while exposing the monomer mixture to a radiation source such as UV light. Static casting methods involve charging the monomeric mixture between two mold sections, one mold section shaped to form the anterior lens surface and the other mold section shaped to form the posterior lens surface, and curing the monomeric mixture while retained in the mold assembly to form a lens, for example, by free radical polymerization of the monomeric mixture. Examples of free radical reaction techniques to cure the lens material include thermal radiation, infrared radiation, electron beam radiation, gammma radiation, ultraviolet (UV). radiation, and the like; or combinations of such techniques may be used. U.S. Pat. No. 5,271,875 describes a static cast molding method that permits molding of a finished lens in a mold cavity defined by a posterior mold and an anterior mold. As an additional method, U.S. Pat. No. 4,555,732 discloses a process where an excess of a monomeric mixture is cured by spincasting in a mold to form a shaped article having an anterior lens surface and a relatively large thickness, and the posterior surface of the cured spincast article is subsequently lathed to provide a contact lens having the desired thickness and posterior lens surface. 
     When polymerizing the monomeric mixture by the thermal technique discussed above to form crosslinked polymers, a resin or metal material that is capable of withstanding high temperatures, i.e., thermally stable, should be employed as a contact lens mold. For example, in injection molding, the resin should have a heat deflection temperature of at least 350° C. and a hardness of at least 100 on the Rockwell Hardness Scale (M scale). Suitable resins include, but are not limited to, engineering plastics based on polyetherimide resins (e.g., ULTEM™ available from General Electric Co., Polymers Product Dept.); polyamide-imide plastics (e.g., TORLON available from Amoco Performance Products); polyphenylene sulfide plastics (e.g., RYTON™ available from Phillips Petroleum Co.); polysulfone and polyarylsulfone plastics (e.g., UDEL™ and RADEL™ available from Amoco Performance Products); polythalamide plastics (e.g., AMODEL available from Amoco Performance Products); polyketone plastics (e.g., KADEL™ available from Amoco Performance Products); various liquid crystal polymer resins (e.g., XYDAR™ available from Amoco Performance Products) and the like. 
     Optionally, the monomeric mixtures herein may include additional components according to the specific type of lens being produced. For example, when producing rigid gas-permeable (RGP) materials, the monomeric mixture may include in addition to the foregoing trifluorvinyl containing monomers, one or more additional crosslinking agents, a small amount of a wetting monomer; and optionally other agents such as strengthening agents or UV absorbing or dye monomers. The wetting agents can include those wetting agents known in the prior art for making RGP materials. The amount of wetting monomer used can be adjusted within limits to provide sufficient wetting characteristics so as to maintain a stable tear film while at the same time keeping a sufficiently low water content, e.g., a polymer system containing less than about 5 wt. % water. 
     When producing a hydrogel lens, the monomeric mixture may include in addition to the foregoing trifluorovinyl containing monomers, at least a diluent that is ultimately replaced with water when the polymerization product is hydrated to form a hydrogel. Generally, the water content of the hydrogel is greater than about 5 wt. % and more commonly between about 10 to about 80 wt. %. The amount of diluent used should be less than about 50 wt. % and in most cases, the diluent content will be less than about 30 wt. %. However, in a particular polymer system, the actual limit will be dictated by the solubility of the various monomers in the diluent. In order to produce an optically clear copolymer, it is important that a phase separation does not occur between the comonomers and the diluent, or the diluent and the final copolymer. 
     Furthermore, the maximum amount of diluent which may be used will depend on the amount of swelling the diluent causes the final polymers. Excessive swelling will or may cause the copolymer to collapse when the diluent is replaced with water upon hydration. Suitable diluents include, but are not limited to, ethylene glycol; glycerine; liquid poly(ethylene glycol); alcohols; alcohol/water mixtures; ethylene oxide/propylene oxide block copolymers; low molecular weight linear poly(2-hydroxyethy lmethacrylate)s; glycol esters of lactic acid; formamides; ketones; dialkylsulfoxides; butyl carbitol; and the like and mixtures thereof. If necessary, it may be desirable to remove residual diluent from the lens before edge-finishing operations which can be accomplished by evaporation at or near ambient pressure or under vacuum. An elevated temperature can be employed to shorten the time necessary to evaporate the diluent. The time, temperature and pressure conditions for the solvent removal step will vary depending on such factors as the volatility of the diluent and the specific monomeric components, as can be readily determined by one skilled in the art. If desired the monomeric mixture used to produce the hydrogel lens may further include additional crosslinking agents as well as wetting agents known in the prior art for making hydrogel materials. 
     The contact lenses obtained herein may be subjected to optional machining operations. For example, the optional machining steps may include buffing or polishing a lens edge and/or surface. Generally, such machining processes may be performed before or after the product is released from a mold part, e.g., the lens is dry released from the mold by employing vacuum tweezers to lift the lens from the mold, after which the lens is transferred by means of mechanical tweezers to a second set of vacuum tweezers and placed against a rotating surface to smooth the surface or edges. The lens may then be turned over in order to machine the other side of the lens. 
     The lens may then be transferred to individual lens packages containing a buffered saline solution. The saline solution may be added to the package either before or after transfer of the lens. Appropriate packaging designs and materials are known in the art. A plastic package is releasably sealed with a film. Suitable sealing films are known in the art and include foils, polymer films and mixtures thereof. The sealed packages containing the lenses are then sterilized to ensure a sterile product. Suitable sterilization means and conditions are known in the art and include, for example, autoclaving. 
     As one skilled in the art will readily appreciate other steps may be included in the molding and packaging process described above. Such other steps can include, for example, coating the formed lens, surface treating, the lens during formation (e.g., via mold transfer), inspecting the lens, discarding defective lenses, cleaning the mold halves, reusing the mold halves, and the like and combinations thereof. 
     The following examples are provided to enable one skilled in the art to practice the invention and are merely illustrative of the invention. The examples should not be read as limiting the scope of the invention as defined in the claims. Various homopolymers and copolymers films were formed and characterized by standard testing procedures such as:
     1. Modulus (g/mm 2 ) and elongation were measured per ASTM 1708 employing an Instron (Model 4502) instrument where the film sample was immersed in borate buffered saline; an appropriate size of the film sample was gauge length 22 mm and width 4.75 mm, where the sample further has ends forming a dogbone shape to accommodate gripping of the sample with clamps of the Instron instrument, and a thickness of 200±50 microns.   2. Tensile strength (g/mm 2 ) was measured per ASTM test method D1708a.   3. Oxygen permeabilities (also referred to as Dk) were determined by the following procedure. Other methods and/or instruments may be used as long as the oxygen permeability values obtained therefrom are equivalent to the described method. The oxygen permeability of the films were measured by the polarographic method (ANSI Z80.20-1998) using an O2 Permeometer Model 201T instrument (Createch, Albany, Calif. USA) having a probe containing a central, circular gold cathode at its end and a silver anode insulated from the cathode. Measurements are taken only on pre-inspected pinhole-free, flat film samples of three different center thicknesses ranging from 150 to 600 microns. Center thickness measurements of the film samples may be measured using a Rehder ET-1 electronic thickness gauge. Generally, the film samples have the shape of a circular disk. Measurements are taken with the film sample and probe immersed in a bath containing circulating phosphate buffered saline (PBS) equilibrated at 35° C.+/−0.2°. Prior to immersing the probe and film sample in the PBS bath, the film sample is placed and centered on the cathode premoistened with the equilibrated PBS, ensuring no air bubbles or excess PBS exists between the cathode and the film sample, and the film sample is then secured to the probe with a mounting cap, with the cathode portion of the probe contacting only the film sample. For silicone films, it is frequently useful to employ a Teflon polymer membrane, e.g., having a circular disk shape, between the probe cathode and the film sample. In such cases, the Teflon membrane is first placed on the pre-moistened cathode, and then the film sample is placed on the Teflon membrane, ensuring no air bubbles or excess PBS exists beneath the Teflon membrane or film sample. Once measurements are collected, only data with correlation coefficient value (R 2 ) of 0.97 or higher should be entered into the calculation of Dk value. At least two Dk measurements per thickness, and meeting R 2  value, are obtained. Using known regression analyses, oxygen permeability (Dk) is calculated from the film samples having at least three different thicknesses. Any film samples hydrated with solutions other than PBS are first soaked in purified water and allowed to equilibrate for at least 24 hours, and then soaked in PHB and allowed to equilibrate for at least 12 hours. The instruments are regularly cleaned and regularly calibrated using RGP standards. Upper and lower limits are established by calculating a +/−8.8% of the Repository values established by William J. Benjamin, et al.,  The Oxygen Permeability of Reference Materials , Optom Vis Sci 7 (12s): 95 (1997), the disclosure of which is incorporated herein in its entirety:   

     
       
         
           
               
               
               
               
             
               
                   
               
               
                 MATERIAL NAME 
                 Repository Values 
                 Lower Limit 
                 Upper Limit 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Fluoroperm 30 
                 26.2 
                 24 
                 29 
               
               
                 Menicon EX 
                 62.4 
                 56 
                 66 
               
               
                 Quantum II 
                 92.9 
                 85 
                 101 
               
               
                   
               
            
           
         
       
         
         4. Refractive index was measured per typical methods on hydrated samples using a refractometer. 
         5. Static Contact Angle (SCA)—The instrument used for this measurement was an AST Products Video Contact Angle System (VCA) 2500XE. This instrument utilizes a low-power microscope that produces a sharply defined image of the water drop, which is captured immediately on the computer screen. Surface Tension of the water used for analysis was periodically measured by the dynamic contact angle method and averaged 73 dynes/cm. The water was 80 μl drawn into the VCA system microsyringe, and 0.6 μl drops were dispensed from the syringe onto the sample. The contact angle is calculated by placing five markers along the circumference of the drop as shown below. The software generated a curve representing the circumference of the drop and calculated the contact angle of the drop with respect to the surface on both sides of the drop. The contact angle (θ) is shown for the left side of the drop as shown in  FIG. 4 . All films were received in water, and soaked in HPLC water for 15 minutes prior to analysis. Sections of the films were placed onto a clean glass slide and allowed to dry overnight in a nitrogen dry box. Five drops of water were used to measure the contact angle of each sample. 
       
    
     In the following examples, the properties of such films derived from the claimed crosslinked polymers and combinations of various comonomers with prepolymers are described. 
     EXAMPLE 1 
     This example illustrates the preparation of a 3-(4-[trifluorovinyloxy]phenyl)propyl terminated poly(dimethylsiloxane) having a number average molecular weight (M n ) of 1523 and a polydispersity (PD) of 1.35 (as determined using SEC and by comparison to standards of known molecular weight) and of the formula 
                         
wherein n is an average of 8.
 
     To a solution of hydride terminated poly(dimethylsiloxane) obtained from Aldrich Chemical Co. (Milwaukee, Wis.) (average M n  580 g/mol, 3.47 g) and 4-(trifluorovinyloxy)allylbenzene (3.87 g, 17.9 mmol) prepared from 1-bromo-4-(trifluorovinyloxy)benzene obtained from Oakwood Products, Inc. (West Columbia, S.C.) using procedures set forth in the literature (e.g.,  Polymer Preprints,  39(1), p. 530.(1998)) in tetrahydrofuran/1,4-dioxane (2:1 v/v, 36 mL) was added 10% solution of platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in xylenes (0.01 mL) and the solution was heated 15 hours at 60° C. The solvents were removed from the cooled solution at reduced pressure and the crude product was purified via column chromatography (0-50% dichloromethane/pentane, silica gel, 5×5 cm) to provide a product as a colorless oil (3.95 g, 66%):  1 H NMR (CDCl 3 , 400 MHz) δ 7.15 (d, J=8 Hz, 4 H), 7.00 (d, J=8 Hz, 4 H), 2.60 (t, J=8 Hz, 4 H), 1.66-1.60 (m, 4 H), 0.57 (t, J=8 Hz, 4 H), 0.07 (s, approximately 63 H). 
     EXAMPLES 2-5 AND COMPARATIVE EXAMPLE A 
     Various proportions of 3-(4-[trifluorovinyloxy]phenyl)propyl terminated poly(dimethylsiloxane) (T 2 D 8 ) of Example 1 and 1,1,1-tris(4-[trifluorovinyloxy]phenyl)ethane (T 3 ) (crosslinker) obtained from Oakwood Products, Inc., (West Columbia, S.C.), were dissolved with gentle heating and stirring and each of the warm solutions was clamped between silanized glass plates with a Teflon tape spacer. Each of the glass plates containing the solution was heated for 20 hours at 195° C. under a nitrogen atmosphere. The cooled, transparent materials ranged from an organic soluble (i.e., dichloromethane), viscous oil (0% T 3 ) to a brittle, insoluble film (100% T 3 ). The properties of the polymers of Examples 2-5 were determined to demonstrate modified mechanical properties as a function of crosslinking density. These results are set forth below in Table 1. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Ex./Comp. Ex. 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 2 
                 3 
                 4 
                 5 
                 A 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 T 2 D 8 /T 3  (w/w) 
                 0/100 a   
                 25/75 
                 50/50 
                 75/25 b   
                 100/0 c   
               
               
                 Modulus (g/mm 2 ) 
                 — 
                 4962(211) 
                 3692(85)  
                 — 
                 — 
               
               
                 Elongation (%) 
                 — 
                 66(7) 
                 72(2) 
                 — 
                 — 
               
               
                 Tensile Strength 
                 — 
                 4091(415) 
                 785(44) 
                 — 
                 — 
               
               
                 (g/mm 2 ) 
               
               
                 Dk 
                 20.5 
                 — 
                 70.3 
                 — 
                 — 
               
               
                 Refractive Index 
                 1.516 
                 — 
                 1.515 
                 — 
                 — 
               
               
                   
               
               
                 Numbers in parenthesis are standard deviation for last digits 
               
               
                   a Sample shattered; 
               
               
                   b sample tore; 
               
               
                   c soluble, viscous oil 
               
            
           
         
       
     
     EXAMPLES 6-8 
     Poly(perfluorocyclobutane) with 4-(trifluorovinyloxy)benzoic Acid as Wetting Agent 
     Various proportions of 4-(trifluorovinyloxy)benzoic acid (TA) prepared from 1-bromo4-(trifluorovinyloxy)benzene obtained from Oakwood Products, Inc. (West Columbia, S.C.) using procedures set forth in the literature (e.g.,  Polymer Preprints,  43(1), p. 487 (2002)), 3-(4-[trifluorovinyloxy]phenyl)propyl terminated poly(dimethylsiloxane) (T 2 D 8 ) of Example 1 and 1,1,1-(4-[trifluorovinyloxy]phenyl)ethane (T 3 ) were dissolved with stirring and gentle heat. The weight ratio of T 2 D 8  to T 3  was held constant at 50:50 for all samples and the amount of TA was varied. The warm solution was clamped between silanized glass plates using Teflon tape spacer and heated under a nitrogen atmosphere at approximately 195° C. for 20 hours. The cooled, transparent, tack-free films were removed from the glass plates and further analyzed. Equilibrium water uptake was measured by measuring mass increase of film after soaking in deionized water (DI) up to 67 hours. Multiple static contact angle (SCA) measurements were conducted and reported. These results are set forth below in Table 2. 
                     TABLE 2                  Wetting properties of T 2 D 8 /T 3  films with TA wetting agent                         Example                                 6   7   8                                                 TA (w/w %)   0     3.4   8.7           SCA (°)   104(1)   91(2)   95(2)           Water (w/w %)   0.0   1.8   2.2                       Number in parenthesis represents standard deviation for last digit            
The observed decrease in contact angle and increase in water content indicates increased surface wettability/hydrophilicity.
 
     EXAMPLE 9 
     Copolymerization of T end-capped poly(alkyl ether), poly(siloxane), and poly(PFCB) prepolymers 
     A monomeric mixture was prepared by dissolving 0.42 g of 4-(trifluorovinyloxy)benzoate terminated poly(ethylene glycol) (1) having a M n  of 1006, a weight average molecular weight (M w ) of 1234 and a PD of 1.23, 3-(4-[trifluorovinyloxy]phenyl)propyl terminated poly(dimethylsiloxane) (2) of Example 1, and 0.43 g (1.11 mmol) of 2,2-bis(4-[trifluorovinyloxy]phenyl)-1,1,1,3,3,3-hexafluoropropane (3), with stirring and gentle heating. The warm solution (insoluble at ambient temperature) was clamped between silanized glass plates with a Teflon tape spacer and heated at 195° C. for 40 hours under nitrogen purge to afford a viscous, transparent oil (1.28 g, 100%); SEC (THF, PS standards). The reaction scheme of this example is generally set forth in  FIG. 5  wherein m and n and x, y, and z are such that the copolymer has a M n =3641, M w =14664, and PD=4.03. The weight average molecular weight (M w ) was measured at various points during curing. These results are set forth below in Table 3. 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                   
                 Weight average 
                   
               
               
                 Cure time 
                 molecular weight (g/mol) 
               
            
           
           
               
               
               
               
               
            
               
                 (h) 
                 1 
                 2 
                 3 
                 Copolymer 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 1234 
                 2054 
                 N/A 
                 N/A 
               
               
                 20 
                 4993 
                 8478 
                 4133 
                  6836 
               
               
                 40 
                 7668 
                 15914  
                 7498 
                 14664 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 10 
     Synthesis of end-capped poly(ethylene oxide) prepolymer (prepolymer 1) 
     A solution of 4-(trifluorovinyloxy)benzoyl chloride (1.85 g, 7.8 mmol) prepared from 1-bromo-4-(trifluorovinyloxy)benzene obtained from Oakwood Products, Inc. (West Columbia, S.C.) using procedures set forth in the literature (e.g.,  Polymer Preprints,  43(1), p. 487 (2002)) in tetrahydrofuran (5 mL) was treated with a solution of poly(ethylene oxide) having a M n  of 300 (0.78 g, 2.6 mmol) and triethylamine (1.21 mL, 8.7 mmol) in tetrahydrofuran (5 mL) dropwise under inert atmosphere. After 15 hours at ambient temperature, the reaction mixture was diluted in dichloromethane (30 mL), washed with NaHCO 3 (aq) (0.25 M, 1×25 mL), dried over Na 2 SO 4 , filtered, and solvents were removed under reduced pressure. The crude oil was purified by column chromatography (3×3 cm, silica gel, 0-50% dichloromethane/pentane) and solvents removed under reduced pressure to afford the product as a viscous oil (0.42 g, 23%):  1 H NMR (CDCl 3 ,400 MHz): δ 8.06 (d, 4 H, J=8 Hz), 7.11 (d, 4 H, J=8 Hz), 4.48 (br, 4 H), 3.79 (br, 4 H), 3.61 (br, 22.3 H); SEC (THF, PS standards): M n =1006 g/mol, M w =1234 g/mol, and a PD 1.23. This reaction is generally shown below in Scheme 1. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 11 
     Synthesis of end-capped poly(ethylene oxide-block-propylene oxide-block-ethylene oxide) prepolymer (prepolymer 2) 
     Polyoxamer 108 supplied as Pluronic F38 (4700 g/mol, 3.45 g), obtained from BASF Co. (Florham Park, N.J.) was reacted using substantially the same procedure described in Example 10 to afford the product as a solid (2.01 g, 54%): GPC (THF, PS standards): M n =9637 g/mol, M w =8761 g/mol, PD=1.10;  1 H NMR (CDCl 3 , 400 MHz); δ 8.08 (d, J=8Hz, 4H), 7.13 (d, J=8 Hz, 4H), 4.54 (t, J=5 Hz, 4H), 3.82-3.37 (m, 530 H), 1.15-1.11 (m, 60 H). The final product is represented by the following formula: 
                         
wherein x is y and z are such that the product has a M n =9637 g/mol, M w =8761 g/mol, and PD=1.
 
     EXAMPLE 12 
     Synthesis of end-capped poly(perfluoroalkyl ether) prepolymer (prepolymer 3) 
     Fomblin Z DOL 2000 (a hydroxy terminated poly(perfluoroethylene containing glycol)) (2000 g/mol) obtained from Solvay Solexis (Thorofare, N.J.), was reacted using substantially the same procedure described in Example 10 except using dichloromethane instead of tetrahydrofuran as solvent to afford the product as a viscous oil (0.58 g, 17%): GPC (THF, PS standards): M n =1604 g/mol, M w =1656 g/mol, PD=1.05 g/mol;  1 H NMR (CDCl 3 , 400 MHz); δ 8.08 (d, J=8 Hz, 4 H), 7.15 (d, J=8Hz, 4H), 4.67 (m, 4.70-4.64, 4H). The final product is represented by the following formula: 
                         
wherein m and n are such that the product has a M n =1604, M w =1656 g/mol, and PD=1.05.
 
     EXAMPLE 13 
     Samples of the materials from Examples 10-12 were clamped between silanized glass plates with Teflon spacers and heated under nitrogen atmosphere at 195° C. for various times. In each case the isolated products were oils of varied viscosities. The linear polymers were dissolved in tetrahydrofuran (5 mg/mL) and analyzed via GPC (relative to PS standards) to demonstrate increase in molecular weight as a function of thermal cure time. The molecular weight analysis of the polymerized products are set forth below in Table 4. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Molecular Weight Analysis of Thermal Trifluorovinylarylether 
               
               
                 end-capped Poly(alkyl ether) Polymerization 
               
               
                 at 195° C. as Determined by SEC 
               
            
           
           
               
               
               
               
            
               
                   
                 Prepolymer 1 
                 Prepolymer 2 
                 Prepolymer 3 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Cure 
                 M n   
                   
                 M n   
                   
                 M n   
                   
               
               
                 time (h) 
                 (g/mol) 
                 PD 
                 (g/mol) 
                 PD 
                 (g/mol) 
                 PD 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 0 
                 1006 
                 1.23 
                 9637 
                 1.10 
                 1604 
                 1.05 
               
               
                 20 
                 2123 
                 2.35 
                 13205 
                 1.43 
                 2815 
                 1.45 
               
               
                 40 
                 2945 
                 2.60 
                 19529 
                 1.82 
                 4707 
                 1.71 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 14 
     Synthesis of 2,4,6,8,10-pentamethyl-2,4,6,8,10-penta(3-[4-trifluorovinyloxyphenyl]propyl)cyclopentasiloxane (cyclo-(TD) 5 ) 
     A solution of 2,4,6,8,10-pentamethylcyclopentasiloxane (0.34 g, 1.13 mmol) and 4-(trifluorovinyloxy)allylbenzene (1.83 g, 8.55 mmol) in 2:1 tetrahydrofuran/1,4-dioxane (17 mL) was treated with 10% platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in xylenes (0.09 mL) and heated at 60° C. for 15 hours. The cooled solution was concentrated under reduced pressure and purified via column chromatography (0-50% ethyl ether/pentane, silica gel, 3×10 cm) to afford the product as a viscous oil (57 mg, 4%):  1 H NMR (CDCl 3 , 400 MHz) δ 7.09 (br, 2 H), 6.99 (br, 2 H), 2.55 (br, 2 H), 1.59 (br, 2 H), 0.5 (br, 2 H), 0.02 (br, 3H). The final product is shown in  FIG. 2 . 
     EXAMPLE 15 
     Homopolymerization of cyclo-(TD) 5    
     The product prepared in Example 14 was clamped between two silanized glass plates with Teflon tape spacer and heated at 195° C. under anitrogen purge for 20 hours to result in a transparent, insoluble, tack-free film: DSC, T g  94 ° C. 
     EXAMPLE 16 
     Crosslinking of 3-(4-[trifluorovinyloxy]phenyl)propyl terminated poly(dimethylsiloxane) (T 2 D 8 ) using cyclo-(TD) 5    
     The product of Example 14 (25 parts) and 3-(4-[trifluorovinyloxy]phenyl)propyl terminated poly(dimethylsiloxane) of Example 1 (75 parts) were dissolved with gentle heat and agitation and polymerized as in Example 16 to result in a transparent, insoluble, tack-free film: DSC, No transitions were observed between −100 to 300° C. 
     EXAMPLE 17 
     Thermal Cast Molding of poly(perfluorocyclobutane) Films 
     1,1,1-Tris(4-[trifluorovinyloxy]phenyl)ethane (2 g, 3.66 mmol), obtained from Oakwood Products, Inc. (West Columbia, S.C.), was melted with gentle heating and clamped between glass plates with Teflon® tape spacers of varied thicknesses. The assemblies were sealed in a heating oven with a constant N 2  purge and heated for 20 hours at 195° C. The cooled films were then removed from the plates to yield a transparent, colorless, glassy film. The films were further cut into wafers for oxygen permeability and refractive index determination: The oxygen permeability for the wafer was a Dk of 20.5 Barrers, and the refractive index was 1.516. 
     EXAMPLE 18 
     Thermal Cast Molding of poly(perfluorocyclobutane) Button 
     1,1,1-Tris(4-[trifluorovinyloxy]phenyl)ethane (2 g, 3.66 mmol), obtained from Oakwood Products, Inc. (West Columbia, S.C.), was added to a flat-bottomed, 15 mm diameter glass test tube. The vessel was sealed in a heating oven with a constant N 2  purge and heated for 68 hours at 155° C. The cooled vessel was removed from the oven and test tube to yield a transparent, colorless, glassy button for lathing into a Rigid, Gas-Permeable (RGP) contact lens. 
     EXAMPLE 19 
     Machining of Lens from poly(perfluorocyclobutane) Button 
     The poly(perfluorocyclobutane) button prepared in Example 18 was machine lathed using processes and procedures well known in the art on a DAC material table using a feed rate of 2.5 (cut amount 0.3 mm) for rough lathing and finished using a feed rate of 1.0 (cut amount 0.05 mm) to afford a transparent, rigid ophthalmic lens of a quality comparable to current commercial gas-permeable lenses. 
     It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. For example, the functions described above and implemented as the best mode for operating the present invention are for illustration purposes only. Other arrangements and methods may be implemented by those skilled in the art without departing from the scope and spirit of this invention. Moreover, those skilled in the art will envision other modifications within the scope and spirit of the features and advantages appended hereto.