Condensed Matter Physics, Materials Science, Surfaces, Coatings and Films, Multidisciplinary
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Scopus Publications
Scopus Publications
Structural evolution, charge transport, hopping conduction, and electrochemical response of Co2+ substituted spinel ferrites Jyothi A Goudar, Thrinethra S N, Sharanappa Chapi, Murugendrappa M V Journal of Physics D Applied Physics, 2026 Electrochemical and temperature-dependent transport studies of Co-doped Ni ferrite nanoparticles, Ni 1− x Co x Fe 2 O 4 ( x = 0.1 and 0.9) were prepared using a simple auto-combustion method. FTIR spectra exhibit characteristic tetrahedral and octahedral sites, with an average force constant of 1.910 × 10 5 dyne cm −1 , confirming strong metal-oxygen bonding in the spinel ferrite structure. X-ray diffraction results indicate an average crystallite size of approximately 33–38 nm, consistent with morphological features observed in SEM micrographs. X-ray photoelectron spectroscopy spectra confirm the presence of Ni 2+ , Co 2+ , and Fe 3+ ions in the NC ferrite nanoparticles. Electrical properties were analysed over various frequencies and temperatures. The NC ferrite nanoparticles exhibited frequency-dependent behaviour, relaxation dielectric response and thermally activated characteristics, indicating their semiconducting nature. The frequency dependence of AC conductivity at various temperatures follows Jonscher’s power law, with conductivity 1.003 × 10 −5 S cm −1 at 453 K (NC-1). NC-1 sample exhibited the best dielectric performance and conductivity, likely due to efficient charge transport via polaron hopping between mixed valence states. The electrochemical investigations revealed a reversible and stable capacitive behaviour, as evidenced by quasi-rectangular cyclic voltammetry profiles and consistent impedance response. Overall, the NC ferrite nanoparticles have potential applications in multifunctional electronic applications.
Green Production of Black Pepper Leaves Extract Doped PVA/Guar Gum Blend Films for Promising Sustainable Food Packaging Applications Vanita Ghatti, Shrishail Pattadkal, Sharanappa Chapi, Vidya Gopi, Gangasagara Thimmappa Vidyavathi, et al. Journal of Food Process Engineering, 2026 ABSTRACT This study aims to prepare black pepper leaf extract (BPL)‐doped poly(vinyl alcohol) (PVA) and Guar gum (GG) (PGBPL) blend films via solvent casting technique for active food packaging applications. The prepared blend films were subjected to structural, thermal, morphological, and surface studies using various characterization techniques, including FTIR‐ATR, XRD, TGA, AFM, and WCA. The interaction among the PVA, GG, and BPL was confirmed by FTIR analysis. Adding BPL to the PVA/GG films increased the water contact angle from 66.47° to 89.52°, resulting in amorphous, thermally stable, and hydrophilic blend films. Mechanical testing showed a significant rise in elongation at break from 249.78% to 394.32%, indicating greater flexibility, while the tensile strength and Young's modulus decreased from 21.7 to 7.86 MPa and 24.48 to 23.65 MPa. The results of swelling and chemical resistance demonstrated better barrier qualities than those of clean PVA films. Importantly, migration values confirmed food compatibility and remained well below regulatory limits. The migratory values recorded for the films were lower than the overall migration limit of 10 mg/dm 2 . These findings indicate that PVA/GG/BPL films are promising for biodegradable food packaging and could also have future applications in wound healing.
AmmPatch: A Visual, Flexible, and Reusable Film Sensor for Ammonia Gas Arti Rodge, Niraj Koyalwar, Sushil Jaiswal, Sohel Shaikh, Siddiqui Al Misbah Noori Siddique, Deepa Bogle, Mustafa Attar, Sharanappa Chapi, Kashinath Bogle Advanced Engineering Materials, 2026 Reliable detection of ammonia (NH 3 ) is essential for environmental monitoring, industrial safety, and public health protection. Here, we report a flexible, paper‐based colorimetric NH 3 sensor patch fabricated by deep‐coating bromocresol green (BCG)–polyvinylpyrrolidone (PVP) composite onto a porous Whatman filter paper substrate, named as “AmmPatch” . The sensing mechanism is governed by a reversible protonation–deprotonation equilibrium of BCG, producing a distinct yellow‐to‐blue color transition upon exposure to NH 3 . Quantitative optical response analysis demonstrated a rapid response (<30 ms) , excellent linearity over the 10–100 ppm concentration range, and a limit of detection near 5 ppm, suitable for safe exposure monitoring. The sensor maintained consistent performance across varying temperature (20°C–36°C) and humidity (27%–92%) conditions and exhibited negligible signal drift during 50 days of continuous testing , confirming exceptional stability and reproducibility. Ultraviolet‐visible spectroscopy (UV–Vis) and Fourier transform infrared spectroscopy (FTIR) spectroscopy confirmed that NH 3 induces reversible proton abstraction from the sulfonephthalein groups of BCG, leading to optical switching between protonated‐deprotonated forms. The flexible, adhesive, and low‐cost design of the patch enables on‐site and real‐time monitoring when integrated with digital color analysis or smart device interfaces. This work establishes a scalable, visually intuitive, and environmentally robust colorimetric sensing platform for practical NH 3 detection in industrial, and occupational safety applications.
Exploring Structural and Electrical Behavior of Nanostructured Polypyrrole/Strontium Titanate Composites for CO2 Sensor S. Mytreyi, Sharanappa Chapi, Sutar Rani Ananda, Nagaraj Nandihalli, M. V. Murugendrappa Micro, 2025 The current research presents the synthesis, characterization, and application of a novel gas sensor based on polypyrrole/strontium titanate (PPy/STO) nanocomposites for the selective detection of CO2. Utilizing chemical oxidative polymerization, PPy and PPy/STO nanocomposites with varying STO (10–50) wt.% were synthesized and characterized. The structural and morphological analysis confirms the formation of spherical structure and well-dispersed PPy nanoparticles with increasing crystallinity and interaction of STO in PPy chain particle compactness as the STO content increases. The integration of perovskite STO within the conducting polymer matrix enhances the electronic structure, porosity, and surface area of the composite, promoting improved gas sensing performance. Electrical impedance spectroscopy reveals that the composites exhibit a frequency-dependent dielectric response and conduction attributed to charge carrier mobility and interfacial polarization effects. PPy/STO 20% exhibits highest conductivity and dielectric constants of 0.03604 Scm−1 and 1.074 × 104, respectively. Real-time CO2 sensing experiments conducted at 50 °C demonstrate good sensitivity, stability, and rapid response/recovery characteristics, particularly for the PPy/STO 10% and 40% composites. These findings highlight the potential of PPy/STO nanocomposites as flexible, lightweight, and efficient materials for portable CO2 gas sensors, addressing the growing needs for environmental and health monitoring.
Protan triggered colorimetric and fluorometric responsive coumarin coupled imidazole as Co2+ sensor, DFT and zebrafish bioimaging studies Aravind R. Nesaragi, Jyoti Nagalik, Sharanappa Chapi, Sharanakumar T. M., Venuprasad K. D., Naveen Kumar Kalagatur, Sudhakar Poda, Sanjeev R. Inamdar, Shivarudrappa H. P., Rafa Almeer Scientific Reports, 2025 This study elucidates a novel Co 2+ ion fluorescence chemosensor 6-bromo-3-(2-(2-(4-nitrophenyl)-4,5-diphenyl-1 H -imidazol-1-yl)thiazol-4-yl)-2 H -chromen-2-one (NIC), which integrates imidazole and coumarin-thiazole moiety evolved over other frequently occurring metal ions. Fluorescence spectra are specifically used to study the complexation of NIC with different metal ions in an acetonotrile: water mixture (8:2) at room temperature. When Co 2+ was present, NIC shows a notable quenching of fluorescence at 450 nm as a result of a complex forming which was accompanied by the emergence of a new band at 515 nm in the uv visible spectrum. Also, the colour of NIC was changed from yellow to brown which was evident from naked eyes. The sensor NIC demonstrated its high sensitivity towards Co 2+ ions with a limit of detection (LOD) of 7 µM. The Job’s plot validates the 1:1 binding stoichiometry between Co 2+ and NIC. The chemosensor NIC also exhibited colorimetric and fluorometric sensing ability with a visible colorimetric response to Trifluoroacetic acid (TFA). Further, the study was also validated with zebrafish bioimaging studies.
Acid Vapor Responsive Coumarin Coupled Imidazole as Colorimetric and Fluorometric Co2+ Sensor, DFT, and Zebrafish Bioimaging Studies Aravind R. Nesaragi, Jyoti Nagalik, Sharanappa Chapi, Nisha Bansal, Thakur Gurjeet Singh, Venuprasad K. D., Naveen Kumar Kalagatur, Sanjeev R. Inamdar, Shivarudrappa H. P., Nabil Al‐Zaqri Luminescence, 2025 This work describes a novel Co 2+ ion sensor 3‐(2‐(2‐(4‐nitrophenyl)‐4,5‐diphenyl‐1 H ‐imidazol‐1‐yl)thiazol‐4‐yl)‐2 H ‐chromen‐2‐one ( NBIC ) comprising imidazole and a coumarin‐thiazole moiety. When Co 2+ is present, NBIC shows a notable quenching of fluorescence at 450 nm as a result of complex formation. The limit of detection was found to be 7 μM under optimal conditions. It was discovered that the sensor was quite selective for Co 2+ ions despite many competing ions. The chemosensor NBIC also exhibited colorimetric and fluorometric sensing ability with a visible colorimetric response to trifluoroacetic acid (TFA). The Job's plot validates the 1:1 binding stoichiometry between Co 2+ and NBIC . Further, the study was also validated with zebrafish bioimaging studies.
Stimuli-responsive delivery systems using carbohydrate polymers: A review Hossein Madineh, Fatemeh Mansourinia, Payam Zarrintaj, Maryam Poostchi, Przemysław Gnatowski, Justyna Kucinska-Lipka, Mehdi Ghaffari, Mohamed S. Hasanin, Sharanappa Chapi, Mohsen Khodadadi Yazdi, Milad Ashrafizadeh, Tomasz Bączek, Mohammad Reza Saeb, Guizhen Wang International Journal of Biological Macromolecules, 2025
Studying the effect of KCl addition on the optical properties and morphological of the solid polymer electrolyte film International Journal of Chemtech Research, 2014