This is a review of the current state of research in the field of the methods of magnetic fluid synthesis. It focuses on analysis of the methods that use magnetic nanoparticles in an inert coating.

Flat surfaces with different patterns of hydrophobic spots were employed for experimental investigation of boiling heat transfer. In one case, hydrophobic spots were created on a smooth copper surface and on a surface coated with arrays of micrococoons from silicon oxide nanowires by vapor deposition of a fluoropolymer. In the second case, a hydrophobic coating was deposited on heater surfaces with cavity microstructures formed by laser ablation and chemisorption of fluorinated methoxysilane. Water under saturation conditions at atmospheric pressure was used as the working liquid. The temperature of the heating surface was varied from 100 to 125 °C, and the maximum value of the heat flux was 160 W/cm². Boiling heat transfer on the test biphilic surfaces was significantly (up to 600%) higher than on non-biphilic surfaces. Surface texture, the shape of hydrophobic regions, and the method of their creation tested in this study did not show a significant effect on heat transfer. The boiling heat transfer rate was found to depend on the size of hydrophobic spots, the distance between them, and hence the number of spots. The highest heat transfer efficiency was detected for the surface with the largest number of hydrophobic spots. After long-term experiments (up to 3 years), the heat transfer coefficient on the obtained surfaces remained higher than on the smooth copper surface. Biphilic surfaces with arrays of cavities formed by laser ablation turned out to be the most stable during prolonged contact with boiling water.

A technology has been developed for the synthesis of arrays of oriented microropes and cocoon-like microstructures consisting of silicon oxide nanowires on a copper substrate with barrier layers of silicon dioxide, molybdenum, and tungsten. In experiments, a copper surface coated with a tungsten layer showed the best stability and technological applicability. Experiments were performed to study pool boiling heat transfer on copper heaters with nanomodified surfaces under saturation conditions. A comparison of the data on heat transfer enhancement on smooth and nanomodified hydrophilic and hydrophobic copper surfaces was made. Relatively high heat transfer coefficients were observed on copper surfaces with a tungsten barrier layer initially coated with microropes and micrococoons. The experiments showed that microropes from nanowires were not resistant to boiling; micrococoons from nanowires were more stable. Superhydrophobic surfaces were produced by hot-wire chemical vapor deposition (HWCVD) of fluoropolymer coatings on micrococoons. In the boiling experiments, the greatest heat transfer enhancement was obtained on such surfaces. The fluoropolymer coating was shown to lose its continuity. As a result, a random biphilic coating was formed and intense bubble boiling occurred in local hydrophobic areas of the fluoropolymer, resulting in heat transfer enhancement.

For the first time, aligned arrays of bundles (“microropes”) of silica nanowires were synthesized from a monosilane-hydrogen mixture by gas-jet electron beam plasma chemical vapor deposition method. The synthesis was performed on single-crystal silicon substrates coated by micron-sized particles of stannic catalyst. A bundle (“microrope”) of silica nanowires each of which is about 15 nm in diameter grows from a catalyst particle. It seems that the synthesis proceeds by the vapor-liquid-solid mechanism, and several nanowires grow synchronously from the surface of one catalyst particle. The “microrope” growth rate was about 25 nm/s at a synthesis temperature of 400°C. A possible growth model was proposed to explain these results.