Cytop

The micro channel structure of the device is fabricated in a glass wafer by common procedures (Figure 4.14). To allow sealing of the channels, the whole surface is coated with CYTOP, a Teflon -like polymer. On the one hand it forms a bondable layer and on the other it makes the micro channel surface strongly hydrophopic. Bonding with a CYTOP-coated cover glass plate occurs under moderate pressure at 180 °C. Because sometimes the CYTOP layer peels off and disturbs the fluid flow behavior, the whole device is fabricated in polydimethylsiloxane (PDMS) [71]. 

Another pefluoropolymer of this type has been developed by Asahi Glass and is available on the market under the trade name CYTOP . This polymer is prepared by cyclopolymerization of perfluorodiene. Its structure is shown in Figure 8.2.7... 

CYTOP has physical and chemical properties similar to PTFE and PFA. Its tensile strength and yield strength are higher than those of PTFE and PFA. It also has unique optical properties its films are transparent in the range from 200 to 700 nm and its clarity is very high even in the UV region.8 The properties of CYTOP are shown in Table 8.2.9 CYTOP is soluble in selected fluorinated solvents. Such solutions have a very low surface tension, which allows them to be spread onto porous materials and to cover the entire surface. Films without pinholes and of uniform thickness can be prepared from solutions.8... 

Physical and Mechanical Properties of CYTOP Compared with Competitive Polymers... 

Therapeutic indications a2(A)Interferon is presently approved for the management of hairy cell leukemia. More than 90% of patients treated with a interferon have shown resolution of cytope-nia, reduction in the incidence of serious infection, and reduction in the need for transfusions. Other interferons are being tested in the treatment of various tumors, including squamous cell carcinoma, melanoma, and multiple myeloma, among others. 

Amorphous perfluoroplastics developed by DuPont (Teflon AF) and Asahi Glass (Cytop) contain bulky structures that are responsible for the absence of crystallinity. When Teflon AF was irradiated by low-energy x-rays, it was found that the inclusion of the dioxole monomer not only improves the optical properties but also increases the radiation tolerance of the homopolymer [43]. 

Cytop (Asahi) CF2=CFO(CF2)nCF=CF2 Optically clear, used in corrosive envirorrments, e.g. computer chip manufacture. 

They are developing high-performance MEAs using candidate materials for improving power density such as high lEC ionomers, new ionomers with high oxygen solubility, and soluble fluoropolymers (Cytop) [91]. 

Cytop. [Asahi Glass] Fluoropolymer highly transparent polymer for optics, electronics, chemical industry, etc. 

Salamon DJ, Nusbacher J, Stroupe T, Wilson JH, Hanrahan JB (2004) Red cell and platelet-hound IgG penicillin antibodies in a patient with thrombocytopenia. Semin Thromb Hemost 30 273—283 Shuhnan NR (1964) A mechanism of cell destruction in individuals sensitized to foreign antigens and its implications in autoimmunity. Ann Int Med 60 506-521 Shuhnan NR, Reid DM (1993) Mechanisms of drag-induced hnmunologically mediated cytope-nias. Transfus Med Rev 7 215-229... 

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... 

Naritomi, M. Dec. 1996. CYTOP Amorphous Fluoropolymers for Low Loss POF Proc. POF-Asia-Pacific Forum, Tokyo. 

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