Data storage coating

Fig. 7.10 Plant for coating data storage disks with carrier transport system...

Fig. 1.11 Plant for individual coating of data storage disks...

One use of AFMs currently being investigated by computer firms is for data storage. A method has been put forward that involves a large array of AFM tips and a polymer-coated storage disk. To record data, a current is passed through the tip raising its temperature to 400°C. The polymer in the immediate vicinity of the tip is softened... 

Optics und hence guided wave velocity can be controlled with great precision acceptable attenuation loss. Possible uses in conventional optics and optical data storage, pboiochromic and ablative systems. Optical sensors e g. based on coated fibres. 

Pure iron particles, coated to inhibit oxidation, are now used to an increasing extent for data storage and may ultimately totally displace the ferrites. 

Promising new analytical tools are further enzymatic analysis, coated wire electrodes, high-pressure liquid chromotography, sulfide electrode use, and use of computers for data storage and retrieval and for monitoring laboratory instrumentation. 

Yu et al. [36] have reported applications of pyrryl fulgides with respect to optical data storage. More than 500 UV-irradiation and photobleaching (He-Ne laser, 632.8 nm) cycles of an optical disk coated with PMMA thin film doped with pyrryl fulgide without fatigue resistance of formation photodecomposed species were demonstrated. 

A novel approach to data storage applications involves a glassy carbon electrode with a coating of [Ru(bipy)2(PVP)Cl]Cl, where PVP is poly-4-vinylpyridine. The rotating electrode oxidizes iron(II) at 640 mV [the polymer coating will inhibit iron(II) oxidation until ruthenium(II) centres are oxidized to ruthenium(III)]. If the electrode is irradiated, a photochemically mediated substitution of the chloro hgand by an aquo ligand will occur and, after this radiation, a more positive potential (740 mV) is required to oxidize iron(II). Thus if the electrode potential is held between 640 and 740 mV a yes / no device is possible since irradiation will eliminate the flow of current. ... 

Figure 2. Schematic diagrams of resistive SThM probes a) Wollaston wire type [34,35], b) micro-machined coated Si cantilever [37] and c) data storage doped Si probe [55].

Chui et al. [55] also describe high resolution silicon (piezo)resistive cantilevers designed not for SThM, but for high-density data storage. An array of probes are used to write 10-50 nm diameter pits in a spinning polymer coated silicon... 

The light-induced synthesis of polymers is the topic of Part III. While the various modes of photoinitiation of polymerization processes are discussed in Chapter 10, related technical applications are treated in Chapter 11. The latter include curing of coatings and dental systems, printing plates (used to print newspapers), holography (important for data storage), and the synthesis of block-and-graft copolymers. 

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