Natural dye cyanidin extracted from red cabbage and adsorbed on the surface of polyacrylonitrile (PAN) in the presence of epichlorohydrin coupling agent to form transparent environmental-friendly thin-film sensor was achieved. The potential thin film showed successful sensor behavior and demonstrated gradual and reversible sensing change in the pH range of 2.0-11.0. Visual and Lucid color change of the thin film was observed at inclined pH value; fuchsia color at pH 1-3, purple color at pH 6-8, and blue color at pH 10-11. Structural identification of the thin-film sensor provided evidence of physical adsorption of cyanidin on the surface of PAN via epichlorohydrin coupling agent as prevailed by FTIR spectroscopy. Moreover, the thin-film sensor demonstrated thermal stability up to 105°C, as onset degradation temperature, as verified by thermogravimetric analysis (TGA) and its first derivative (DTG) techniques. Moreover, the pH-sensing change of the 1-mm-thick thin film was checked by UV-Vis technique. The oligomer formation of cyanidin, mediated by epichlorohydrin, lead to the formation of stable and successful adsorption on the surface of PAN with uniform and soft appearance. The concept of the reversible stability and response time of the thin film sensor were also proved. The cyanidin-based PAN conjugate sensor act as a novel environmental-friendly sensor with the following specifications: low cost, easy fabrication, high sensing capacity, appropriate reversible stability, and response time specifications. Such exquisite specifications of the thin-film sensor adapt it to put into service in optoelectronics and microelectronic devices.

No abstract

Bolaamphiphilic polyphenol flavonoids were successfully revealed as a sustainable coating at the solid/liquid interface of an aluminium surface in an aqueous solution. Polyphenol flavonoids extracted from brown onions demonstrated the presence of bolaamphiphiles above 600 ppm. Characterization of the polyphenol flavonoids coating was performed using spectroscopic 1 H-nuclear magnetic resonance and attenuated total reflectance Fourier-transform infrared techniques for chemical identification, UV-vis and optical microscopy techniques were used for bolaamphiphilic microstructures assessment, and a scanning electron microscope was used for the assessment of surface morphology. Variant operating conditions used to show best coating efficacy were as follows: concentration = 600 ppm, solution pH = 10 in the presence of PO 4 3À ion crosslinker, operating temperature = 10 C, microwave pre-irradiation time = 5 s, and turbulent flow of the solution = 300 rpm. Maximum coating efficacy showed a coating efficacy of 97%. The suitability of several adsorption isotherms, like Langmuir, Temkin, and Freundlich, was tested to fit our data. Equilibrium constant values were in favour of successful coating, especially at lower temperatures (20 C). Spontaneous (negative ΔG ) and high affinities of coating material to the surface were revealed from thermodynamic parameters (ΔH and ΔS ). Conclusively, such research is meant to emphasize our continuous support for the use of plant waste in artificial sectors such as coating of metals, and for their economic feasibility and low cost as high efficacy renewable materials.

No abstract