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Conductive Coatings with Core-Shell Particles

Currently, carbon nanotubes (CNT) are of major interest for their apphcations in nanomaterials and nano devices, and composite particles based on a CNT core and ICP shell have been reported recently [77,78]. Yu and coworkers successfully synthesized multi-waUed carbon nanotubes (MWNT) coated with a PPy shell with core-shell morphology [78] the composite particles obtained showed an improvement of conductivity and the redox behavior of PPy. [Pg.200]

Corrosion protection by ICPs has been well documented in several reviews [136-141]. The use of ICP-based core-shell latexes for the corrosion protection of steel is a relatively new field of research, and a recent review has proposed the exploitation of such possibihties [142]. In a recent study, we found that ICP-based core-shell latexes offer the possibility of achieving anticorrosion properties [143], though the presence of pinholes or scratches in the coatings enhances the corrosion rate of metals. This problem may be due to poor dispersion of the composite particles in the insulating resin systems, and future research will need to develop conductive polymer-based anticorrosive primers for metals. The anticorrosive properties of PANI-coated polystyrene latex microspheres has been reported recently [144]. PS-PANI composite particles with core-shell structure were prepared by chemical oxidative polymerization of anihne monomer in the presence of a PVP-stabilized PS latex suspension. The reduced form of the particle was obtained by adding hydrazine mono hydrate to the suspension. Both oxidized and reduced PANI-PS particles were used to obtain a PANI-PS-coated iron electrode (PANl-PS-Fe). Pure PANI... [Pg.214]

Similarly, Pd, Ag, and Pd-Ag nanoclusters on alumina have been prepared by the polyol method [230]. Dend-rimer encapsulated metal nanoclusters can be obtained by the thermal degradation of the organic dendrimers [368]. If salts of different metals are reduced one after the other in the presence of a support, core-shell type metallic particles are produced. In this case the presence of the support is vital for the success of the preparation. For example, the stepwise reduction of Cu and Pt salts in the presence of a conductive carbon support (Vulcan XC 72) generates copper nanoparticles (6-8 nm) that are coated with smaller particles of Pt (1-2 nm). This system has been found to be a powerful electrocatalyst which exhibits improved CO tolerance combined with high electrocatalytic efficiency. For details see Section 3.7 [53,369]. [Pg.36]

It is frequently desirable to cover a given particle with a layer of different chemical composition. In doing so, one can alter the surface reaction sites, as well as optical, magnetic, conductive, and other properties of the dispersed matter. Finally, if a material of a given particle shape is needed, but cannot be obtained directly, it is possible to use cores of a different composition but of the desired morphology and coat them with a shell of the chemical compound of interest. This approach combines the needed overall morphology with the surface reactive sites of choice. [Pg.392]

Unlike the porous membrane, colloidal particles (such as PS or silica particle) are another type of template for the preparation of CPCs (Figure 11.10c). In previous work, core/shell PS/PANI composite particles were prepared by chemical oxidative seeded dispersion polymerization. A conventional coating protocol was employed as follows. The aniline monomer was dissolved in a strongly acidic solution in the presence of the PS seed latex (an alternative method involves using a miscible aniline hydrochloride monomer without external acid). Then polymerization was initiated by the addition of oxidant aqueous solution. The suspended PS particles were coated with PANI by in situ deposition of the formed conducting polymer or oligomer from the aqueous phase. [Pg.480]

Different from the PANI-coated composite particle, microcapsules or core/shell-structured particles containing PANI with low pH or high conductivity as the core material are interesting because they do not need to additional dedoping treatment. [Pg.743]

Sapurina et al. have reported the synthesis of PANI-coated waterborne polyurethane latexes in the presence of a polymeric stabihzer, polyvinylpyrrolidone (PVP). The composite particles showed a conductivity of 10 S cm i, with good colloidal and mechanical properties [73]. Recently, Huang et al. synthesized a series of PPy-coated styrene-butyl acrylate (SBA) core-shell latex particles [74], The Tg of the composite particles was shown to be determined mainly by the core material. It was reported that the conductivity of the hybrid particles could be tuned by varying the butyl acrylate content in the SBA copolymer. The composite particles showed a conductivity of 0.17 S cm Composite particles having a photochromic dye as the core and ICP as shell, and possessing properties of photoluminescence, have been studied by Jang etal. [75]. Thin PEDOT-coated PS particles (Fig. 6.14) were reported for self-assembled crystalline coUoidal arrays with a stop band in the visible regime by Han and coworkers [76]. [Pg.200]

It is possible to enhance the conductivity of polymeric composites by the formation of a core-sheU fillers, where the core could be either conductor or dielectric and the shell is a conductor. This is of practical interest in the technology of the production of glues and varnishes. For example, the conductivity of dielectric Sn02 particles coated with a silver layer (8 vol%) is substantially increased to a = 1 X 10 S m ), versus only o = 2xl0 Sm for a mechanical mixture of Sn02 and 16 vol% of Ag powders. The silver layer was prepared by thermally treating an Ag(I)-containing polymer. [Pg.190]

Numerous researches have been conducted to modify abrasive particles for scratch reduction. Mixed abrasive slurry and various dispersants were used for the development of hne slurries [44,45] slurries made of abrasives with soft polymer coating are also proposed [46] polymer-core silica-shell composite abrasives were reported too [47]. However, most of these modified/composite abrasive slurries remain experimental and have not received wide industrial acceptance yet, because of challenges in particle control and difficulty in cleaning the residual abrasives. [Pg.452]


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Coatings conductivity

Conducting coat

Conductive coatings

Conductive particles

Core-shell

Particle coating

Particle conductivity

Particle with shell

Particles, conduction

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