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1

Zinc oxide nanoparticles as photo-catalytic and anti-bacterial pigment for alkyd resin based coating

Kavitha Sri A., Sivaraj M., Rajkumar S., Ruby Shelin A., Sajitha L.P., Jeyasubramanian K., Jeen Robert R.B., Hikku G.S.

Archives of Materials Science and Engineering

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2022

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Vol. 118, nr 1

29--35

EN

Purpose: Recently, there has been an upsurge among people around the world in maintaining a sustainable and hygienic environment. This is due to the over-exploitation of recourses causing environmental pollution and spreading bacterial infections. In this regard, scientists are motivated to develop smart coatings where environmental pollutants and bacterial cells are degraded when in contact with their surfaces. Design/methodology/approach: In our previous report, ZnO nanoparticles (NPs) were prepared using the precipitation technique, showing good photocatalytic and antibacterial activity [1]. In this context, the present study details the use of ZnO NPs as pigment for the fabrication of alkyd resin-based self-cleaning coating. The coating was developed by mixing ZnO NPs and alkyd resin along with the additives using the ball milling technique. The developed coating was characterized using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, and water contact angle measurements. Findings: To elucidate the self-cleaning and hygienic behaviour of the ZnO/alkyd resin coating, the dried coating was exposed to crystal violet (CV) solution as a model dye pollutant and bacterial strains to assess its photocatalytic and antibacterial activity. The droplets of CV solution placed over the coating almost degraded after 360 min of exposure to sunlight owing to the presence of ZnO NPs in the coating. Further, the coating exhibits reasonable antibacterial activity against E. coli and P. aeruginosa whereas it displays low antibacterial activity against S. aureus. Research limitations/implications: Even though, the self-cleaning coating shows promising results, tuning the activity of the photo-catalytic pigment can improve the pollutant degradation efficiency and elevate bactericidal activity. Originality/value: ZnO NPs-impregnated alkyd resin coating for self-cleaning applications is novel.

2

Fabrication of dye sensitized solar cell using chemically tuned CuO nanoparticles prepared by sol-gel method

Prabhin V. S., Jeyasubramanian K., Romulus N. R., Singh N. N.

Archives of Materials Science and Engineering

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2017

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Vol. 83, nr 1

5--9

EN

This work details about the isolation of CuO nanoflakes by a simple precipitation technique. Further it is coated over ITO substrate using spin coating technique. DSS cell capabilities were checked by placing a drop of plant dye derived from pomegranate. Design/methodology/approach: CuO nano flakes, a novel Nano sized metal oxide have been synthesized by sol-gel method. The synthesised flakes were characterized by using XRD (X-ray diffraction), FESEM, UV-VIS and PL measurements techniques. XRD studies show that, the copper oxide formed has monoclinic structure. Findings: The grain size of the synthesized copper oxide nanoflakes were measured from FESEM and found that the size was around 200 nm. The UV-VIS measurement show that the band gap of CuO nanoflakes were found to be 3.03 eV, which is in the range of a good semiconductor. Finally, the dye sensitized solar cell was fabricated and its power conversion efficiency η (PCE) was determined. Practical implications: The search for green sources or generators of energy is considered as one of the priorities in today's society and occupies many policy maker’s agenda. It is believed that nanocrystalline photovoltaic devices are becoming viable contender for large scale future solar energy converters.

3

Starch bioplastic film as an alternative food-packaging material

Jeyasubramanian K., Balachander R.

Journal of Achievements in Materials and Manufacturing Engineering

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2016

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Vol. 75, nr 2

78--84

EN

Purpose: To synthesize bioplastics on a small scale from starch available in potato and to study the characteristics of the same when pectin is blended with it. Design/methodology/approach: The bioplastics are fabricated manually using starch extracted from potato and glycerol. Pectin was blended to this combination to synthesize another set of bioplastic films. The characterization of the obtained films were done by FTIR spectroscopy, SEM analysis, water solubility test, water absorption test and biodegradability test. Findings: The synthesized films were found to be physically similar to the commercially available films. However on further study, it was found that the former could not provide adequate strength as compared to the latter though the former could still be used for light duty purposes. The advantage of the former over the latter was that it was found to be degradable. Research limitations/implications: Environment-friendly manufacture of the films on a large scale is yet to be studied upon. Economic and eco-friendly methods to improve the tensile strength of the bioplastics to bring it at par with the commercial plastic films are to be found out. Practical implications: The starch and starch-pectin blend films were found to be water soluble. However, they were also found to absorb water which could be implied as a disadvantage. The main objective of biodegradability was achieved. Originality/value: Though researches are going on in the field of biodegradable films, the addition of pectin to starch to improve the characteristics of degradable films is an area where more research has to be done. This paper inculcates the study of adding pectin to starch and the resulting changes in the characteristics of the starch film.

4

Surface morphology and topographical studies of fluorine doped tin oxide as transparent conducting film

Jeyasubramanian K., Gokul Raja T. S.

Archives of Materials Science and Engineering

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2016

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Vol. 78, nr 2

66--70

EN

Purpose: This paper deals about the preparation and characterization of transparent conducting metal oxide doped with fluorine for superhydrophobic applications. Design/methodology/approach: Fluorine doped tin oxide(FTO) have been deposited on glass substrate employing an inexpensive spray pyrolysis route. Uniform coating of thin film was controlled by the parameters like flow rate, exposure duration, temperature of pyrolysis process etc. Findings: Fluorine doped SnO2 was confirmed from FTIR studies. Transparent nature of the coating was evaluated through UV-vis. spectroscopy. Electrical resistivity of the deposited film measured using source meter showed a least resistance of 13 Ω. AFM & SEM analysis revealed the texture of nano SnO2 in the range of 100-300 nm. Unevenness is one of the prerequisite for achieving superhydrophobic nature, which has been explored through AFM results. Practical implications: An attempt has been done to fabricate fluorine doped tin oxide thin film using spray pyrolysis technique may be used for developing super hydrophobic coating application. Originality/value: This study aims to reduce the cost of forming superhydrophobic surfaces on comparison with the process like plasma etching and sensitizing with nanoparticles, etc.

5

Synthesis, Structural Characterization, Redox and Antimicrobial Studies of Schiff Base Copper(II), Nickel(II), Cobalt(II), Manganese(ii), Zinc(II) and Oxovanadium(ii) Complexes derived from benzil and 2-Aminobenzyl Alcohol

Raman N., Kulandaisamy A., Jeyasubramanian K.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 8

1085-1094

EN

Neutral complexes of Cu(II), Ni(II), Co(II), Mn(II), VO(II) and Zn(II) have been synthesized from the Schiff base derived from benzil and 2-aminobenzyl alcohol. The structural features have been arrived from their microanalytical, IR, UV-Vis, 1H NMR, Mass and ESR spectral data. All of the complexes exhibit square-planar geometry except the Mn(II) and VO(II) complexes. The Mn(II) chelate shows an octahedral environment and the VO(II) chelate exists in a square-pyramidal geometry. The monomeric and non-electrolytic nature of the complexes is evidenced by their magnetic susceptibility and low conductance data. The cyclic voltammogram of copper complex in acetonitrile solution shows two quasi reversible peaks for the Cu(II)/Cu(III) and Cu(II)/Cu(I) couples. The X-band ESR spectra of the Cu(II) and VO(II) complexes in DMSO at 300 and 77 K were recorded and their salient features are reported. The biological activity of the metal chelates against the bacteria Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa and Shigella flexneri are also reported. Most of the complexes have higher activity than that of the free Schiff base and the control.