English Ukrainian Russian

Navigation

Links

ISP NAS of Ukraine

Content

Technological methods
1 2 3 4 5 6 7

International projectsSTCU 6362Technological methods

Synthesis of carbon fluoroxide NPs by electrochemical etching and surface modification of NPs by various functional groups to stabilize their properties

Synthesis of NPs was performed by electrochemical etching of polycrystalline SiC substrates. After the etching, the porous layers formed on the top of the SiC wafers were rinsed with DI water, dried and collected by mechanical scratching leading to a brownish powder. To separate the por-SiC and NPs, the powders were rinsed with EtOH under centrifugation. As the SiC wafers were used for several times, the residues of por-SiC were thoroughly removed from the wafer under mechanical scraping and EtOH rinse steps.

Fig.1. Scheme of the samples preparation

A

B

C

D

Fig. 2. Carbon fluorooxide (CFO):A. Electrochemical cell (60 cm2);
B. Ethanolic solution of the CFO (1 mg/ml);
Solid powders of the CFO (C) and por-SiC (D) (Table 1.1).

Synthesis of carbonised fumed silica

Nanodispersed fumed silica powder with a specific surface area of 295 m2 /g was used as a nanostructured silica matrix. It was dispersed in toluene solution of phenyltrimethoxysilane (PhTMS, 1.73 ml of PhTMS per 10 ml of toluene) at a temperature of 70°C for 4 h in the presence of triethylamine as a catalyst. PhTMS reacted with the silica surface through the reaction of electrophilic substitution of proton in the silanol groups present at the surface. This resulted in the formation of ≡Si-O-Si≡ bonds and in the elimination of methanol:

≡Si-OH + (H3CO)3SiC6H5 → ≡Si-O-Si(OCH3)2C6H5 + CH3OH

Phenyl containing groups -Si(OCH3)2C6H5 appeared to be covalently bonded to silica surface through Si-O-Si bonding bridge. Obtained products – phenylsilicas, were washed out with the dissolvent and dried at 80 - 100°C.

Fabrication of nanoporous graphitic carbon films by magnetron plasma enhanced chemical vapour deposition (MgPECVD)

Thin carbonized films were deposited by the low-temperature (150°C) magnetron deposition technique in RF plasma from the gas mixture CH4+Ar or C2H2+Ar using two types of targets (Si or SiC). The films were deposited onto single-crystalline silicon substrate and on the dielectric layer of SiO2-Si structures at very low RF power. Then these samples will be thermally annealed to graphitized of the carbon film.


Back to Top