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The influence of substrate temperature and film thickness on the nanostructure of titanium (HCP) and silver (FCC) thin films deposited on glass substrates under UHV conditions by electron beam evaporation is investigated. The preferred orientation, nanostrain and stacking and twin fault probabilities in Ag and Ti films are determined as a function of film thickness and substrate temperature. A (111) preferred orientation is observed for silver films, which is dependent on both the film thickness and substrate temperature, with the highest value at a substrate temperature of 500 K. Ti/glass films showed a (002) preferred orientation. Nanostructural parameters such as the crystallite size (size of coherently diffracting domains) and nanostrain are evaluated using the Scherrer and Stocks–Wilson relations, the Williamson–Hall plot, and the single-Voigt (SV), double-Voigt (DV) and Warren–Averbach (WA) methods. Analysis of the results obtained using these methods showed that the most suitable approaches to x-ray diffraction line broadening analysis, applicable to both FCC and HCP polycrystalline thin film structures, are SV, DV and WA. The results show that the crystallite sizes increase with substrate temperature and film thickness, while the nanostrain and lattice constants decrease with thickness. The crystallite size distribution function was obtained from the size broadened part of the DV function, and the results show a shift in the maximum to larger sizes with increasing temperature and thickness. [ABSTRACT FROM AUTHOR]

A biopolymer coating on copper was prepared based on chitosan nanocomposite and its corrosion inhibition efficiency was investigated. Inclusion of silica nanoparticles substantially reduces swelling ratio of chitosan coating while enhancing its thermal stability. The corrosion resistance of chitosan-based coatings is improved by introducing 2-mercaptobenzothiazole and silica in the matrix. It is found that upon crosslinking the chitosan coatings, a higher corrosion resistance could be achieved and the highest inhibition efficiency for chitosan nanocomposite coatings is calculated as 85%. The corrosion mechanism is found closely related to mass transition and diffusion process, and also the polarization resistance contributes to the impedance. Calculated impedance using Kramers-Kronig transformation shows good agreement with experimental values, thus validating the impedance measurements. This study exhibits the enhanced efficiency of nanocomposite and potential of chitosan coatings in corrosion prevention for copper., Competing Interests: Declaration of competing interest The authors confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

A novel and facile method is developed for rapid estimation of lactic acid bacterial concentration in fermented milk. Growth of bacteria in a liquid changes physicochemical property of the medium and its behavior at solid-liquid interface. Wettability determines characteristic of solid-liquid interface. Nano-rod, helical tetragonal and L-shaped morphologies were designed and fabricated. Hydrophobicity and zeta potential were measured for dried surfaces of 5 dairy bacterial strains. Relationship between microbial population and changes in solid-liquid interface was studied by wettability and surface free energy measurements. Due to hydrophobic surface property of conventional dairy strains, they strongly affect solid-liquid and liquid-vapor surface tensions when dispersed in a liquid, which are dependent on the bacterial concentration. Response surface methodology results showed that type and concentration of bacteria, droplet volume and solid-surface morphology affect wettability significantly. Higher hydrophobicity resulted in higher ∆θ (absolute value of the difference between the pure physiological saline and the bacterial suspension contact angles) dependence on the bacterial concentration. Probiotic bacteria concentration in fermented milk was estimated using the proposed method. A direct relationship was obtained between milk contact angle and bacterial concentration. Results show that this physical method can be applied for rapid estimation of bacterial concentration., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this work, the surface engineering method is used to produce Mn helical star-shaped (pine-tree-like) nanosculptured thin films with three-, four-, and fivefold symmetries on Cu substrates using an oblique angle deposition technique together with rotation of the sample holder at certain angles. Nano structure and morphologies of the produced samples were obtained by means of atomic force microscope and field emission scanning electron microscope. Raman spectroscopy of the Mn/Cu samples impregnated by 4,4'-bipyridine (C 10 H 8 N 2 ) solution with different concentrations, zidovudine (C 10 H 13 N 5 O 4 ), and L-histidine (C 6 H 9 N 3 O 2 ) was performed using 532 nm laser wavelength. A high degree of enhancement is achieved on Raman spectroscopy of all of these specimens. Comparison of the surface-enhanced Raman spectroscopy (SERS) results for 4,4' bipyridine (bipy) obtained in this work with the published literature using Ag and Au substrates in different shapes showed a significant enhancement improvement by using Mn sculptured structures. Reduction of the bipy concentration changed the enhancement factor. Enhancement factors of 10 7 and 10 5 were obtained for threefold symmetry sample using 2.885 × 10 -2 and 10 -3  mol L -1 bipy concentrations, respectively. Surface-enhanced Raman spectroscopy results of this work show that Mn nanostructures designed and engineered in this work can not only replace Ag and Au materials, but also provide a much higher enhancement factor.