Whiskers organic

The nanostructured thin-film electrode was first developed at 3M Company by Debe et al. [40] and Debe [41], who prepared thin films of oriented crystalline organic whiskers on which Ft had been deposited. The film was then transferred to the membrane surface using a decal method, and a nanostructured thin-film catalyst-coated membrane was formed as shown in Figure 2.10. Interestingly, both the nanostructured thin-film (NSTF) catalyst and the CL are nonconventional. The latter contains no carbon or additional ionomer and is 20-30 times thinner than the conventional dispersed Pt/ carbon-based CL. In addition, the CL was more durable than conventional CCMs made from Pt/C and Nation ionomer [40]. 

A new angle on the proximity needed between catalyst and the adjacent layer is offered by an alternative thin-film catalyst process requiring neither carbon fibre backup nor channels of Nafion or other ionomer proton conductors (Debe, 2003). Pt-Ru catalysts are deposited by sputtering on oriented crystalline organic whiskers (length about 1 pm), and this assembly is then... 

The supremacy of such layers in terms of catalyst utiliza tion is demonstrated by recent MEA development of the company 3 M [96]. In this design, nanos-tructured films of oriented crystalline organic whiskers form the substrate for a sputter-deposited Pt film. The activity per total mass of Pt of these ultrathin films is about a factor six greater than the mass activity of conventional three-phase CCLs, which affirms the much better catalyst utilization. 

One of my successful harvests from my studies in those days was the development of organic polymer whiskers we synthesized the first organic whisker in the world, which was based on poly(oxymethylene) (POM) [2,3]. We also succeeded in the small-scale mass production of POM whiskers and their application to loudspeaker diaphragms by the development of composite materials with whiskers and polyethylene. 

The catalytic layer used for the DoE cost review [13] is based on a ternary PtCoMn alloy, either supported by carbon or by organic whiskers, as developed by 3M, with a platinum loading of 0.25 mg cm cell area. The cost of the support and the ionomer is insignificant compared to the precious metal cost of the catalytic layer. Most R D is devoted to decreasing the use of precious metal, primarily platinum, while at the same time preserving power density and durability. 

Nanostructured Thin Film (NSTF) Electrode. Debe et al. [59, 60] employed sputter technology and deposited catalyst on a nanostructured thin film (NSTF). This NSTF is an oriented crystalline organic whisker. Perylene red (PR) is a highly useful organic material for growing the NSTF. To form an electrode, the... 

There are organic and inorganic whiskers. Organic whiskers include fibrin whiskers, polyCbutyl acrylate-phenylethylene) whiskers, and so forth, and are usually used in polymers. Inorganic whiskers include metal whiskers and nonmetal whiskers. Metal whiskers are mainly applied in metal matrix composite material. Ceramic whiskers, a kind of nonmetal... 

FIGURE 4-2 SEM images of Pt thin-film catalysts supported on crystalline organic whiskers. Top—cross-section on microstructured catalyst transfer substrate. Bottom—Plainview. Reprinted from Ref. [12], with permission from Elsevier. 

The 3M nanostructured thin film (NSTF) catalyst support has also been well developed, which consists of oriented, nanometer-sized crystalline organic whiskers, synthesized by sublimation and subsequent annealing of an organic... 

A cat s whiskers are among the most perfect organs of touch. 

Scholz and Hasse [377] have shown that crystals of metallic silver can be grown at liquid/liquid interfaces (water with AgNOs -octanol with ferrocene). Depending on the reactants concentrations in both phases, silver crystallized in the form of (1) wires (whiskers with radii from about 50 nm to 50 pm) growing into the organic phase (2) Christmas treelike deposits at the interface and even (3) extremely smooth films of silver. 

Wentzel Kramer-Brillouin approximation, tunneling, 1492 Whewefi, Reverend, 1050 Whiskers, 1327, 1336 White, and organic adsorption. 979 Wieckowski, A., 1146 Will, 1205... 

The types of materials deposited by CVD, range from pure metals to compounds, ceramics, powders, whiskers and composite coatings. The various types of metals and compounds which have been successfully deposited by CVD are shown in table 13.3. In most of these cases, the precursors are metal halides which are unstable in the temperature range of deposition. When suitable halides cannot be obtained, metal-organic compounds can be used. 

---