Rani P. George

Bio: Rani P. George is an academic researcher from Indira Gandhi Centre for Atomic Research. The author has contributed to research in topics: Corrosion & Coating. The author has an hindex of 21, co-authored 50 publications receiving 934 citations. Previous affiliations of Rani P. George include Homi Bhabha National Institute.

Photocatalytic inhibition of microbial adhesion by anodized titanium.

Abstract: Biofouling is one of the concerns in the use of titanium for seawater cooled condensers of power plants. Earlier studies have shown that anodized titanium and its alloys with a thin film of anatase (TiO(2)) on its surface can inhibit attachment of Pseudomonas sp. when illuminated with near-UV light (350 - 380 nm). In the present study, a comparison of the photocatalytic inhibition of microbial attachment on titanium surfaces anodized at different voltages was carried out. Thin films of anatase of varying thickness were produced on titanium grade-2 by anodizing in dilute orthophosphoric acid solution at 30 V, 50 V and 100 V. The photocatalytic efficiency of these anodized surfaces was measured by the methylene blue degradation method. The anodised surfaces were exposed to liquid cultures of Gram-negative Pseudomonas sp., Gram-positive Micrococcus sp. and to a mixed algal culture. Photocatalytic inhibition of microbial attachment was maximum on the titanium surface anodized at 30 V, followed by the surface anodized at 50 V and then at 100 V. The photocatalytic inhibition of microbial attachment was also found to be dependent on the cell wall characteristics of the organism. The Gram-negative Pseudomonas sp. with a lipoproteinaceous outer membrane was the most susceptible to the photocatalytic effect, while the Gram-positive Micrococcus sp. with peptidoglycan cell wall showed moderate susceptibility and the algae with siliceous cell wall showed no susceptibility at all.

Robust nickel-reduced graphene oxide-myristic acid superhydrophobic coating on carbon steel using electrochemical codeposition and its corrosion resistance

Abstract: We report a facile approach to fabricate superhydrophobic (SHP) coating of nickel (Ni)–reduced graphene oxide (rGO)-myristic acid on carbon steel (CS) surface with superior corrosion resistance and self-cleaning ability, using electro-codeposition. The electro-deposition current density and electrolyte bath temperature are optimized to obtain the desired hierarchical surface textures with very high water contact angle (WCA). The microstructure, chemical compositions, surface roughness, and self-cleaning properties were examined using FESEM, XRD, XPS, EDX, AFM, water bouncing etc. A WCA of 174 ± 1.5°, with a sliding angle (SA) of ~1°, was obtained at 60 mA·cm−2 and 45 °C. The FESEM surface morphology showed a hierarchical pinecone structured Ni–rGO composite film. The good adhesion and mechanical stability of SHP coating is achieved by phosphating the surface prior to deposition. The SHP surface showed a two order reduction in the corrosion current density and ~3 orders higher impedance, as compared to uncoated surface. This study demonstrates a new approach for fabricating mechanically and chemically durable SHP coating on CS specimens.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Advanced micro/nanocapsules for self-healing smart anticorrosion coatings

Abstract: Smart self-healing coatings for corrosion protection of metallic substrates (steel, magnesium, and aluminium, and their alloys) have attracted tremendous interest due to their capability to prevent crack propagation in the protective coatings by releasing active agents from micro/nanocapsules, that is, micro/nano particles consisting of a coating layer or a shell (micro/nanocontainers) and core material (solids, droplets of liquids or gases), in a controllable manner. This paper aims to give a concise review on the most recent advances in preparing micro/nanocapsules based on different types of micro/nanocontainers, i.e., organic polymer coatings, inorganic clays, mesoporous silica nanoparticles, polyelectrolyte multilayers, etc. for smart coatings with self-healing properties. The state-of-the-art design and preparation of micro/nanocapsules are highlighted with detailed examples.

Organic–inorganic hybrid sol–gel coatings for metal corrosion protection: a review of recent progress

Abstract: This paper is a review of the most recent and relevant achievements (from 2001 to 2013) on the development of organic–inorganic hybrid (OIH) coatings produced by sol–gel-derived methods to improve resistance to oxidation/corrosion of different metallic substrates and their alloys. This review is focused on the research of OIH coatings based on siloxanes using the sol–gel process conducted at an academic level and aims to summarize the materials developed and identify perspectives for further research. The fundamentals of sol–gel are described, including OIH classification, the interaction with the substrate, their advantages, and limitations. The main precursors used in the synthesis of OIH sol–gel coatings for corrosion protection are also discussed, according to the metallic substrate used. Finally, a multilayer system to improve the resistance to corrosion is proposed, based on OIH coatings produced by the sol–gel process, and the future research challenges are debated.