Browsing by Author "Ramanuj N."

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    Salt spray resistance of superhydrophobic waterborne polyurethane/carbon dots nanocomposites
    (Journal of Materials and Environmental Science, 2022) Bankole-Ojo Olufunso Samuel; Oyedeji Folashade Olatunbosun; Raju K.V.S.N.; Ramanuj N.
    In this study, novel carbon quantum dots (cqds) has been synthesized through the thermal decomposition of the aqueous extract of Phoenix dactylifera fruit pulp. Silane functionalized carbon quantum dots (Scqds) were prepared through the attachment of silane derivatives from tridecafluorooctyltriethoxysilane to the surface of the cqds. Results obtained from FTIR spectroscopy, DLS and TGA studies reveal that silane compounds adhered to the cqds to give Scqds. Silane modification of the cqds changed the wettability from hydrophilicity to hydrophobicity from contact angle measurements. WPU/cqds and WPU/Scqds showed excellent thermal stability from TGA and DTA and exhibited hydrophilicity and superhydrophobicity respectively. Steel substrates coated with WPU/Scqds exhibited superior anti-corrosion properties when compared with steel substrates coated with WPU/cqds. Less than 5% corroded area was obtained for steel substrates coated with WPU/Scqds 0.2% and WPU/Scqds 0.25% after 96 hours when subjected to salt spray test. The intrinsic hydrophobicity of WPU/Scqds appear beneficial to inhibit the permeation of corrosive medium and consequently slow down the corrosion rate.
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    Superhydrophobic siloxane functionalized zirconia, stannia and ceria nanoparticles synthesized through a phyto-mediated route
    (Journal of Applied Surfaces and Interfaces, 2021) Bankole-Ojo Olufunso Samuel; Oyedeji Folashade Olatunbosun; Ramanuj N.
    The suitability of phyto-synthesized metal oxide nanoparticles for producing super-hydrophobic coatings for potential biomedical, agricultural and industrial applications was studied for the first time. ZrO2, CeO2 and SnO2 nanoparticles were synthesized through a green and facile method by using the aqueous leaf extract of the widely distributed Azadirachta indica as capping agent with over 60 % percentage mass yield. Organic groups acting as capping/stabilizing agents and siloxane attachments were identified using Fourier transform infra-red (FTIR). Tiny spherical ZrO2 nanoparticles, angular shaped CeO2 particles and a bed of tiny SnO2 particles with overall predominant particle sizes less than 15 nm were observed using field emission scanning electron microscope (FESEM). As expected, non-wettability of surfaces generally increased with increasing siloxane coupling of the nanoparticles. At a nanoparticle to fluoroalkylsilane mole ratio of 1:1, non-wettable, highly non-wettable and super-hydrophobic surfaces were obtained for CeO2, SnO2 and ZrO2 nanoparticles, respectively. The extent of initial phytochemical adsorption, size of the nanoparticles and extent of agglomeration are major factors that influence the coupling of fluoroalkylsilanes and consequently, the wettability of surfaces produced.