• REZA RASULI

Articles written in Bulletin of Materials Science

• Superhydrophobic and low-hysteresis coating based on rubber-modified TiO$_2$/SiO$_2$ nanoparticles

In this article, the wettability of a superhydrophobic layer from rubber-modified TiO$_2$/SiO$_2$ nanocomposite is studied. The nanocomposites were prepared with various ratios of TiO$_2$ and SiO$_2$ nanoparticles (NPs) and then studied the effect of annealing, UV irradiation and aging after coating on a substrate. Results show that the average contact angle of deionized water droplets on the most hydrophobic coating is $129.5^\circ$, which increases up to $151.0^\circ$ by UV irradiation. In addition, the lowest surface energy of the prepared layers was measured as 29.61 mJ m$^{–2}$. The hydrophobicity of the coating surface was investigated after annealing (at temperatures up to $300^\circ$C), and results show that the maximum contact angle is about $150^\circ$. The dynamics of water droplets on the most hydrophobic coating were investigated by rapid imaging, and results show no hysteresis for surface wetting. Fourier transform infrared spectroscopy shows that UV irradiation causes the formation of C–H functional groups on the surface without considerable change in the hydrophobicity, while the annealing process has no significant effects on the functional groups. The morphology of the coatings was investigated by scanning electron microscopy, and results reveal that the roughness of surfaces increases due to annealing and UV radiation. In addition, a minimum increase in the roughness coefficient is estimated as 73% of the initial value after annealing, which is in agreement with atomic force microscopy results.

• SiO$_2$–TiO$_2$@polyvinylidene fluoride nanocomposite: the icephobicity and wettability

Fabrication of icephobic and hydrophobic coating is a challenge of recent researches. In this article, we study the icephobicity and hydrophobicity of a nanocomposite from silica-titanium oxide nanoparticles in the polyvinylidenefluoride matrix. The surface energy of the prepared nanocomposites was tested by measuring the contact angle of different liquid droplets. Results show that the wettability is dependent on the concentration of nanoparticles, and the minimum surface energy of the prepared surface is 22.6 mJm$^{-2}$. In addition, icephobicity tests for cooled substrate show that the contact angle of the water droplet reduces to about 115° after freezing. Moreover, the icing test in the freezer shows a decrease in humidity freezing on the surface down to 25 g m$^{–2}$. Finally, stability tests in harsh environmental conditions such as UV radiation and heating indicate that the surface is substantially stable.

• # Bulletin of Materials Science

Volume 46, 2023
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020