Partially fluorinated films

Table 1 also indicates that a large water CA hysteresis (CAH) is present for the partially fluorinated films. It is well known that contact angle hysteresis arises from... 

In 1954 the surface fluorination of polyethylene sheets by using a soHd CO2 cooled heat sink was patented (44). Later patents covered the fluorination of PVC (45) and polyethylene bottles (46). Studies of surface fluorination of polymer films have been reported (47). The fluorination of polyethylene powder was described (48) as a fiery intense reaction, which was finally controlled by dilution with an inert gas at reduced pressures. Direct fluorination of polymers was achieved in 1970 (8,49). More recently, surface fluorinations of poly(vinyl fluoride), polycarbonates, polystyrene, and poly(methyl methacrylate), and the surface fluorination of containers have been described (50,51). Partially fluorinated poly(ethylene terephthalate) and polyamides such as nylon have excellent soil release properties as well as high wettabiUty (52,53). The most advanced direct fluorination technology in the area of single-compound synthesis and synthesis of high performance fluids is currently practiced by 3M Co. of St. Paul, Minnesota, and by Exfluor Research Corp. of Austin, Texas. 

Partially fluorinated X-IP has been used for a number of years as an additive in the inert lubricant PFPE film on the surface of a magnetic hard disk to enhance start/stop durability of PFPE lubricants [29,30]. Recently it has been used as a vapor lubricated film on the surface of the disks [31 ]. In order to avoid the PFPE being catalyzed to decomposition by the slider material AI2O3 (refer to Section 3.4), XI -P was also examined as a protective film on the surface of the magnetic heads [25,32]. The results of CSS tests indicate that the thermal stability of the lubricant was greatly improved in the presence of X-1P, and the thickness of X-1P film on the slider surface has an important influence on HDD lubrication properties. 

Although Fe deposition has been less studied than other metals, some reports are available. Deposition on fluorinated organic films, such as partially fluorinated decanethiolate/Au SAMs, shows extensive defluorination of the molecular group to form Fe(II) fluorides, with no evidence for reactions with the C atoms of the chains [75]. Further, for an aromatic thiolate/Au SAM, no degrading side reactions were observed [33]. 

Figure 14.13. UV-visible transmission spectra of partially fluorinated (dFDA/TFDB), perfluorinated (10FEDA/4FMPD), and unfluorinated polyimide (PMDA/ODA) films. 

Table 14.4. Mechanical Properties of Perfluorinated (10FEDA/4FMPD), Partially Fluorinated (6FDA/TFDB), and Unfluorinated (PMDA/ODA) Polyimide Films ...

Emphasis was first placed on the adsorptive behavior of Compound D on the surface of chromium because that metal has the following desirable properties (a) it is an excellent adsorbent for carboxylic acid groups (5) (b) a large body of data is available on the properties of adsorbed, monomolecular films of aliphatic (16), partially fluorinated (13), fully fluorinated (2), and chloro-fluoro carboxylic acids (2) (c) the metal surface can be readily and reproducibly cleaned by standard metal-lographic polishing techniques and (d) there is a hard, coherent, thin-film oxide on the surface (18). 

When organic solvents are used for anodic fluorination, anode passivation (the formation of a nonconducting polymer film on the anode surface that suppresses faradaic current) takes place very often, which results in low efficiency. Moreover, depending on the substrates the use of acetonitrile can yield an acetoamidation byproduct. To prevent acetoamidation and anode passivation, Meurs and his coworkers used an EtaN 3HF ionic liquid as both a solvent and supporting electrolyte (also a fluorine source) for the anodic fluorination of benzenes, naphthalene, olefins, furan, benzofuran, and phenanthroline. They obtained corresponding partially fluorinated products in less than 50% yields (Scheme 8.2) [11]. 

A common feature among F lePcZn and the partially fluorinated F4PcZn and FgPcZn can only be seen in the contribution of a band at 800 nm for films grown on PI. 

Partial fluorination gives a polymer that, like polyethylene, is easy to cast into films but with a greater resistance to oxidation and water penetration. 

It has been demonstrated in this study that by incorporating silica particles, a partially fluorinated polyurethane film can be turned superhydrophobic, despite a large water contact angle hysteresis (sticky superhydrophobic behavior). One major cause for the large CAH is the surface reorganization of the fluorinated polyurethane film upon contact with water. A long PDMS chain can be used to effectively suppress the surface reorganization upon contact with water. 

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