The renewability and ecofriendly nature of vegetable oils make them a competitive candidate to replace depleting petroleum-based mineral oils. However, the poor antiwear properties of vegetable oils restrict them from many industrial applications as lubricants. In the present work, the synergic effect of SiO2 nanoparticles with ionic liquids 1-butyl-3- methylimidazolium tetrafluoroborate and 1-hexyl-3-methylimidazolium tetrafluoroborate as hybrid antiwear additives in enhancing the tribological properties of sesame oil is studied for steel on steel contacts. Morphologies of the worn surfaces and possibilities of tribofilm formation are examined using a field-emission scanning electron microscope and energy-dispersive spectroscopy analysis. A density functional theory analysis is performed to study the existence of intermolecular forces of attraction between ionic liquid and triglyceride molecules. Rheological properties of the blends are evaluated using Anton Paar MCR10 rheometer. Corrosive properties of the oil blends are studied using copper strip corrosion test (ASTM D130).

The limited viscosity range of vegetable oils restricts their effectiveness as a lubricant in numerous applications. In this work, the viscosity improvement with styrene butadiene rubber as an additive in sesame oil is studied and the results are compared with those of the commonly used viscosity improver, ethyl vinyl acetate, using a rheometer. Sesame oil/styrene butadiene rubber blends show higher increment in viscosity than sesame oil/ethyl vinyl acetate blends. The viscosity variations are further validated using Arrhenius model. A computational quantum chemical software, Gaussian 09, is used to evaluate the binding energies between molecules. Ground state electronic structures of molecules are modeled with density functional theory. Thermal properties such as flash, fire, and pour points have also been evaluated for sesame oil/styrene butadiene rubber blends. Chemical oxygen demand and biological oxygen demand are the parameters chosen to evaluate the biodegradability of sesame oil/styrene butadiene rubber blend.

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The manuscript introduces the use of non-electrically polled spin-coated thin polyvinylidene fluoride (PVDF) films as the active layers in a contact electrification-based nanoenergy harvester. The four-layered device utilizes both piezo and triboelectric effect coupled with electrostatic induction. The elucidation of potential generation during contact between crystalline phases ( α and β) of PVDF layer material is investigated in the manuscript. Fourier transform infrared–attenuated total reflectance spectroscopy is carried out to illustrate the α- and β-phases in PVDF pellet, prepared film as well as the film after contact. Dynamic contact mode electrostatic force microscopy (DC-EFM) along with atomic force microscopy is used for the evaluation of reverse piezoelectric, local ferroelectric, triboelectric voltage and adhesive energy of the PVDF films before–after contact process. Quantum chemical calculation is performed using density functional theory to explain possible electron transitions in the active layers between the cylindrically symmetric α-phase and electrical double layer charges in the β-phase of PVDF. The interface study of the film is also carried out both experimentally using DC-EFM and through quantum chemical calculations. The fabricated device with the hybrid piezo-tribo layer promises to be a simple and low-cost energy source for the next-generation self-powered electronic devices. The device can also be used as knock sensor in engines as well as a capacitor.

Depleting resources and increasing environmental pollution caused by the petroleum products made researchers to think about its biodegradable counterparts. Vegetable oils due to its characteristics such as availability, renewability, eco‐friendliness, and biodegradability are progressively encouraged as a replacement for mineral oils in lubricant industry, while enhancement of few properties like the oxidative stability aids in the efficient use of them as the base stock. A generous amount of unsaturation in vegetable oils decreases oxidative stability and improves the pour point. Hence, a compromise between these two properties (pour point and oxidative stability) is critical in vegetable oil‐based lubricant. In this regard, sesame oil (SESO) possesses high pour point, and presence of natural antioxidants in it imparts superior oxidative stability than any other vegetable oils with a higher level of unsaturation. The addition of certain synthetic antioxidants to the SESO helps in the further improvisation of its oxidative stability to suit it for lubricant purpose. In the present work, the oxidative stability of SESO blended with octyl gallate (OG), salicyl hydroxamic acid, 2,5‐di‐tert‐butyl hydroquinone (DTBHQ), and tertbutyl hydroquinone (TBHQ) are assessed using hot oil oxidation test (HOOT) and differential scanning calorimetry (DSC, ASTM E2009‐08). The results are further compared with commercially available mineral oil‐based lubricant, SAE20W40. HOOT results show that a blend of SESO + 1.5%DTBHQ + 0.5%OG possesses higher oxidative stability than other antioxidant blends with SESO. In addition, from the DSC results, it is observed that the oxidative onset temperature (OOT) for abovementioned combination (268.10°C) shows an increase of 46.6% than the value of neat SESO (182.79°C) and is nearer to SAE20W40 (277.38°C). Fourier‐transform infrared spectroscopy results show that SESO + 1.5%DTBHQ + 0.5%OG combination subjected to HOOT hampers oxidation and hence increases the oxidative stability. The tribological properties of neat and antioxidant added SESO are studied using a four‐ball tester. Quantum chemical studies are also performed for antioxidant molecules on the basis of bond dissociation energies, ionisation potential, and HOMO‐LUMO energy gap to identify the dominant antioxidant mechanisms.