Perfluorinated Polymer, CYTOP

Because the high attenuation of PMMA is caused by overtones of the C-H vibrational absorption, the most effective method for obtaining a low-loss POF is to substitute all the hydrogen atoms with heavier atoms such as fluorine, which helps to avoid the water absorption problem mentioned above. The replacement of hydrogen with fluorine also improves the thermal stability, chemical resistance, and electrical properties of POFs. The size of the fluorine atom allows the formation of a uniform and continuous sheath around the carbon-carbon bonds and protects them from attack, thus imparting heightened chemical resistance and stability to the molecule. 

However, compared to the large number of radically polymerizable hydrocarbon monomers, only a few classes of perfluorinated monomers can homopolymerize under normal conditions via a free-radical mechanism. The most typical example is tetrafluoroethylene (TFE), developed by DuPont in 1938. As is well known, poly(tetrafluoroethylene) is opaque white, despite the 

3- dioxole, which possesses a cyclic structure in its monomer unit, and TFE, while Hyflon AD is a copolymer of perfluoro-2,2,4-trifluoro-5-trifluoromethoxy- 

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Also, new polymer elechet materials have been added to the family of electrets, i.e., parylene HT (referred to as polymer AF-4 ) and the amorphous perfluorinated polymer CYTOP. The development of such high-performance electrets is mainly motivated by the apphcation in micro electret power generators (Suzuki 2011 Yang... 

In 1982, the first GI POF was reported. It was a pioneering research that led to the development of a perfluorinated polymer (CYTOP )-based GI POF, named Ludna , which was commercialized by AGG in 2001. At that time, the GI profile was formed by copolymerizing two or three kinds of... 

Perfluorinated dioxole monomers have been used to prepare a series of amorphous fluoropolymers such as Teflon AF and Hyflon AD. A third amorphous fluoropo-lymer, Cytop contains perfluorotetrahydrofuran and perfluorotetrahydropyran rings, but is prepared in a cyclopolymerization process from an acyclic monomer. These amorphous fluoropolymers retain the outstanding chemical, thermal, and surface properties associated with perfluorinated polymers while also having unique electrical, optical, and solubility characteristics. 

All three commercial amorphous fluoropolymers. Teflon AF, Hyflon AD, and Cytop posses a unique set of properties. All dissolve in fluorinated solvents and thus may be spin coated to produce thin hlms and coatings. The polymers may also be extruded and molded using traditional polymer processing techniques. Note that the polymers are not soluble in hydrocarbon solvents or water and retain the chemical and thermal stability of perfluorinated polymers such as Teflon . These polymers have lower density than the well-known semicrystalline perfluorinated polymers such as pTFE that results in lower refractive index, lower thermal conductivity, higher gas permeability, and lower dielectric constant. The polymers are transparent and have excellent mechanical properties below their Tg due to their amorphous character. The presence of a heterocyclic ring in the polymer backbone of these materials is key... 

Nd(POM- )3, gave enhanced luminescence in DMSO-c 6 by minimizing the energy migration during diffusional collisions in the liquid matrix. Kuriki etal. doped the complexes of deuterated l,l,l,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione, [R(fhd-fi()3] (R = Pr, Nd, Er, Tm), into a perfluorocarbon liquid (3 M PF-5080) and into the perfluorinated polymer cyclic transparent optical polymer (CYTOP). A comparison study of the peak positions in the emission spectrum of [Nd(fhd-J)3] in PMMA-afg with that of the same complex in a perfluorocarbon liquid shows that the F3/2 - 19/2 transition in PMMA-afg is shifted to shorter wavelengths. NIR emission around 1550nm was observed for an octupolar Er + complex in PMMA. ... 

These perfluoropolymers have excellent properties in many aspects. However, the preparative methods are complex and expensive and of Cytop is relatively low. Several substituted perfluoro-2-methylene-l,3-dioxolanes (Figure 16.5) have been studied to obtain other perfluorinated polymers. The first example in the class is perfluoro-2-methylene-4-methyl-l,3-dioxolane (Figure 16.5B), which was prepared by DuPont in 1967 through perfluoropyruvyl fluoride prepared from hexafluoro-propylene oxide [7]. Using a similar method, perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolane (Figure 16.5D) was synthesized by Asahi Glass in 1993 [12]. 

To avoid the formation of the crystalline phase, introduction of aliphatic rings into the main chain, which causes it to become twisted, is an effective method. The most well-known amorphous perfluorinated polymers are Teflon AF, Hyflon AD, and CYTOP, developed by DuPont, Solvay Chemicals, and AGC, respectively. The chemical structures of these three polymers are shown in Figure 4.2. They have excellent clarity, solubility in some fluorinated solvents, thermal and chemical durability, low water absorption, and low dielectric properties. In particular, their high transparencies arise from the cyclic structures that exist in the polymer main chains. Teflon AF is a copolymer of 2,2-bis(trifluoromethyl)-4,5-difluoro-... 

DL1 Dlubek, G., Pionteck, J., Sniegocka, M., Hassan, E.M., and Krause-Rehberg, R., Temperature and pressure dependence of the free volume in the perfluorinated polymer glass CYTOP A positron lifetime and pressure-volume-temperature study (experimental data by G. Dlubek), J. Polym. Sci. Part B Polym. Phys., 45, 2519,... 

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