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[en] The demand for developing oil detectors is ever increasing since the cleanup and recovery from oil spill usually take long time. Here we propose oil sensors made of polyaniline (PANI) filled poly(styrene–isoprene–styrene) (SIS) block copolymer composite films with good uniformity and dispersion. The changes in resistivity of the samples in presence of both oil and water media reveal the good sensing ability of SIS–PANI films towards oil in water (dual phase). The morphology and chemical composition of the developed products are characterized by scanning electron microscopy and Fourier transformation infrared spectroscopy. Swelling studies are performed to correlate the sensing response to the structural variations and based on it a mechanism is derived for the dual phase sensing. Contact angle measurements confirm the behavior further. The thermal properties and crystallinity of the composites are also addressed by the thermogravimetric and differential scanning calorimetric studies. The developed oil sensor material is able to withstand extreme temperature condition as well. - Highlights: • We model a dual phase sensor capable of detecting oil in water. • A mechanism is proposed to correlate sensing with diffusion. • In situ polymerization helps in the uniform distribution of filler. • Polymer composite sensor could be used as stickers on oil pipelines
[en] The authors decribe an ultra-sensitive, room temperature, flexible transparent LPG sensor based on the use of a CdO/graphene nanocomposite. The graphene prevents the accumulation of CdO, enhances the surface area, and acts as a gas sensing material. FESEM images show a uniform decoration of CdO nanoparticles on graphene. The CdO/graphene composite was deposited as a film on interdigitated electrodes (IDEs) which then were used for chemiresistive sensing of liquid petroleum gas (LPG) by using a four probe technique. A Resistivity decreases significantly upon exposure to a LPG. The electrical resistance measurement at a constant bias voltage of 0.5 V. The sensor of type CdO/graphene (1 wt.%) exhibits a sensitivity of 600 ppm of LPG at 27 °C. It is a highly selective, stable and sensitive to low concentration of LPG even at room temperature. .
[en] Highlights: • Ocimum tenuiflorum leaf extract and silver nitrate were used to prepare Ag NPs. • Structural, optical and morphological properties of Ag NPs were studied. • The GCE modified with Ag NPs showed a sensitivity of 895.8 μAmM−1cm−2. • Bio-mediated synthesized NPs showed sustainable glucose sensing properties.
[en] A nanocomposite consisting of a few layers of graphene (FLG) and tin dioxide (SnO2) was prepared by ultrasound-assisted synthesis. The uniform SnO2 nanoparticles (NPs) on the FLG were characterized by X-ray diffraction in terms of lattice and phase structure. The functional groups present in the composite were analyzed by FTIR. Electron microscopy (HR-TEM and FE-SEM) was used to study the morphology. The effect of the fraction of FLG present in the nanocomposite was investigated. Sensitivity, selectivity and reproducibility towards resistive sensing of liquid propane gas (LPG) was characterized by the I-V method. The sensor with 1% of FLG on SnO2 operated at a typical voltage of 1 V performs best in giving a rapid and sensitive response even at 27 °C. This proves that the operating temperature of such sensors can be drastically decreased which is in contrast to conventional metal oxide LPG sensors. .
[en] The ongoing revolution in touch panel technology and electronics demands the need for thin films, which are flexible, stretchable, conductive, and highly touch responsive. In this regard, conductive elastomer nanocomposites offer potential solutions for these stipulations; however, viability is limited to the poor dispersion of conductive nanomaterials such as graphene into the matrix. Here, we fabricated a reduced graphene oxide (rGO) and poly(dimethylsiloxane) (PDMS) elastomer based transparent and flexible conductive touch responsive film by dispersing rGO honeycombs uniformly into PDMS elastomer through an ionic liquid (IL) modification. Pursuing a simple, scalable, and safe method of solution casting, this provides a versatile and creative design of a transparent and stretchable rGO/IL-PDMS capacitive touch responsive, where rGO acts as a sensing element. This transparent film with ∼70% transmittance exhibits approximately a five times faster response in comparison to rGO/PDMS film, with negligible degradation over time. The performance of this touch screen film is expected to have applications in the emerging field of foldable electronics.
[en] The authors describe the preparation of PVA/WPPy/hBNNP nanocomposite films by solution casting method from poly(vinyl alcohol) (PVA), water soluble polypyrrole (WPPy), and using hexagonal boron nitride nanoparticles (hBNNP) as a reinforcing filler element. The structural, optical and electrical properties of the material are characterized by FTIR, X-ray diffraction, UV-vis spectroscopy, scanning electron microscopy, atomic force microscopy, thermogravimetric analysis, and by electrochemical impedance spectroscopy. The nanocomposite films are shown to be viable chemiresistive sensors for sensitive and selective detection of liquid petroleum gas (LPG). The effect of hBNNP loading on the sensing performance was investigated. The nanocomposite films possess good mechanical flexibility and improved tensile strength. These PVA/WPPy/hBNNP nanocomposite film showed a maximum sensitivity (S, defined as a signal change compared to pure air) to LPG of up to S = 0.25% at a 600 ppm concentration at room temperature with response/recovery times of ~30/32 min for 6 wt% hBNNP loading in a PVA/WPPy matrix. The nanocomposite with 6 wt% filler loading shows good selectivity for LPG over vapors of benzene, chloroform, ethanol and acetone. Therefore, this sensor film is a good candidate for qualitative detection of LPG. .
[en] Solar energy is conceivably the largest source of renewable energy at our disposal, but vital advances are expected to make solar cells economically viable. Biodegradable and flexible solar cells are currently under extensive investigation for environmentally-friendly electronic applications. Biomaterials based solar cell is emerging due to their sustainable, scalable, abundant, renewable, and environmentally-friendly energy production. This review highlights recent research progress in the emerging group of biomaterials and their integration for flexible solar cell devices. The more emphasis is given to the absolute recyclable solar cell technology, processing conditions and optimized processing conditions to produce a high amount of energy. This review briefly describes the recent progress in these classes of material, covering substrates and semiconductors. A prominent demand still exists for a next-generation of flexible, biodegradable and biocompatible solar cell substrate for ultimate energy generation application.
[en] In this study, zinc sulphide nanoparticles (ZnS NPs) have been synthesized by green synthesis approach. These ZnS NPs were used as nanofiller to fabricate polyvinyl alcohol (PVA) based nanocomposite films via solution casting method. The PVA/ZnS nanocomposite films have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, atomic force microscopy and thermogravimetric analysis. The results from these characterization techniques evidenced the improvement in structural, morphological and thermal properties of PVA/ZnS nanocomposite films and also confirmed the incorporation of ZnS NPs in the PVA matrix. In addition to that, the dielectric properties of the PVA/ZnS nanocomposite films were investigated for different frequencies (50 Hz–1 MHz) and temperatures (40–140 °C) using an impedance analyzer. The values of dielectric constant and dielectric loss of PVA/ZnS nanocomposite films were observed to be 328.93 (50 Hz, 140 °C) and 6.02 (50 Hz, 140 °C) with 3 wt% ZnS NPs content. This enhancement in dielectric properties demonstrated the good interaction between ZnS NPs and PVA matrix. The aforementioned results evidenced that the ZnS NPs were homogeneously distributed within the PVA matrix.
[en] The use of MgO and TiO2 nanofluids at different concentrations was investigated annually to evaluate the distillate output of stepped solar stills. Nanofluids concentrations ranged from 0.1 to 0.2% in the present research work. Results confirm that the stepped solar still distillate output is increased by 45.8%, 33.33%, 20.4% and 4.1% with use of MgO nanofluids (0.2% and 0.1% concentrations) and TiO2 nanofluids (0.2% and 0.1% concentrations). The reason for higher distillate output of MgO nanofluid over TiO2 in stepped solar still is lower specific heat capacity and higher thermal conductivity. Finally, the energy payback time was also calculated, and it was still only 3 months for stepped solar stills with the use of 0.2% nanofluid concentration.
[en] In this work, Graphene Oxide (GO) reinforced novel polymer composites comprising of poly (4-styrenesulfonic acid) (PSSA) and polyvinyl alcohol (PVA) blend matrix have been developed using colloidal processing technique. The properties and the structure of prepared composites were investigated using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), UV–vis spectroscopy (UV), Thermogravimetric analysis (TGA), Polarized optical microscopy (POM), Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The FTIR and Raman spectroscopy analysis indicate the strong interfacial interaction between GO and PSSA/PVA blend matrix. The XRD and SEM analysis confirm that GO was fully exfoliated into individual graphene sheets and dispersed homogeneously within the polymer matrix. The effective reinforcement of GO into PSSA/PVA blend matrix has resulted in the enhancement of dielectric constant. The dielectric constant has increased from 82.67 (50 Hz, 150 °C) for PSSA/PVA (50/50) blend to 297.91 (50 Hz, 150 °C) for PSSA/PVA/GO composites with 3 wt % GO loading. The dielectric loss (tan δ) has increased from 1.56 (50 KHz, 140 °C) for PSSA/PVA (50/50) blend to 2.64 (50 KHz, 140 °C) for PSSA/PVA/GO composites with 3 wt % GO loading. These findings provide a new insight to fabricate flexible, high-k dielectric composite as a promising material for energy storage applications. - Highlights: • Graphene Oxide was prepared from natural graphite using modified Hummers method. • Novel PSSA/PVA/GO composites were prepared by reinforcing GO into PSSA/PVA blend matrix. • Molecular level dispersion of GO in PSSA/PVA blend matrix was successfully achieved. • Enhancement in the dielectric constant was observed due to effective reinforcement of GO in PSSA/PVA blend matrix. • PSSA/PVA/GO composites with high dielectric performances can be considered for energy storage applications.