Alumina polymer coated

If the rf source is applied to the analysis of conducting bulk samples its figures of merit are very similar to those of the dc source [4.208]. This is also shown by comparative depth-profile analyses of commercial coatings an steel [4.209, 4.210]. The capability of the rf source is, however, unsurpassed in the analysis of poorly or nonconducting materials, e.g. anodic alumina films [4.211], chemical vapor deposition (CVD)-coated tool steels [4.212], composite materials such as ceramic coated steel [4.213], coated glass surfaces [4.214], and polymer coatings [4.209, 4.215, 4.216]. These coatings are used for automotive body parts and consist of a number of distinct polymer layers on a metallic substrate. The total thickness of the paint layers is typically more than 100 pm. An example of a quantitative depth profile on prepainted metal-coated steel is shown as in Fig. 4.39. 

Mao, Y. Fung, B.M. Use of alumina with anchored polymer coating as packing material for reversed-phase high performance liquid chromatography. J. Chromatogr., A 1997, 790, 9-15. 

The complex surface chemistry of the metal oxides (section 4.2.1.2) is incompatible with their use in a number of chromatographic techniques. Polymer coated metal oxides are seen as an important approach to extending their scope. Alumina and zirconia particles coated with poly(butadiene), poly(styrene), poly(ethylene oxide), a copolymer of chloromethylstyrene and diethoxymethylvinylsilane and succinylated poly(ethyleneimine), for example, have been prepared for use in reversed-phase, size-exclusion and ion-exchange chromatography [44,46,54,120,134-137]. The methods of preparation are similar to those used for porous silica. 

T. Uchikoshi, S. Furumi, T. Suzuki, and Y. Sakka. Electrophoretic deposition of alumina on conductive polymer-coated ceramic substrates. J. Ceram. Soc. Japan, 114, 55-58 (2006). 

In Polymer-Functionalized Nanoparticles and Nanocomposites. EFTEM was used to evaluate me covalent bonding of polymer coating on nanoparticles and the nanoparticle dispersion, as in a polycarbonate/alumina nanocomposite [120]. 

Boron also reacts with hydroxyl-containing polymers such as cellulose. When exposed to a flame the boron and hydroxyl groups form a glassy ester that coats the substrate and reduces polymer degradation. A similar type of action has been observed in the boron—alumina tfihydrate system. 

The next two examples illustrate more complex surface reaction chemistry that brings about the covalent immobilization of bioactive species such as enzymes and catecholamines. Poly [bis (phenoxy)-phosphazene] (compound 1 ) can be used to coat particles of porous alumina with a high-surface-area film of the polymer (23). A scanning electron micrograph of the surface of a coated particle is shown in Fig. 3. The polymer surface is then nitrated and the arylnitro groups reduced to arylamino units. These then provided reactive sites for the immobilization of enzymes, as shown in Scheme III. 

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