Hanjun Ryu; Sang-Woo Kim
Abstract
Smart sensors and network systems are commonly referred to as Internet of Things (IoT) and are being used to realize a smart society. Although the development of low-power smart systems and large-capacity batteries is increasing the usage time of IoT devices, the time-limited capability of such systems ...
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Smart sensors and network systems are commonly referred to as Internet of Things (IoT) and are being used to realize a smart society. Although the development of low-power smart systems and large-capacity batteries is increasing the usage time of IoT devices, the time-limited capability of such systems reveals a need for self-powered sensors and systems for sustained IoT use. Mechanical energy is easily accessible from the environment to power sensors and systems. The triboelectric nanogenerator (TENG) converts mechanical energy into electric energy was first introduced in January 2012 by Wang et al., and we describe recent developments in the triboelectric properties of the polymers because the contact electrification between the two different materials is a key factor of TENG. This review article discusses the four operating modes of TENG, the working mechanism, the theoretical modelling of the vertical TENG, and the research aspects of the material.
Yanyu Zhang; Palas Baran Pati; Haining Tian
Abstract
Organic semiconducting polymer nano-particles, as nano-photocatalysts for light driven proton reduction, have been prepared by using Triton X-100 as surfactant. The nano-photocatalysts prepared by Triton X-100 showed well dispersibility in water and no precipitation observed after photocatalysis. The ...
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Organic semiconducting polymer nano-particles, as nano-photocatalysts for light driven proton reduction, have been prepared by using Triton X-100 as surfactant. The nano-photocatalysts prepared by Triton X-100 showed well dispersibility in water and no precipitation observed after photocatalysis. The effect of molecular weight and concentration on photocatalysis has been investigated, indicating that the particle size shows significant influence on photocatalytic performance. The sample with 100 µg/ml photocatalysts gave the best hydrogen evolution amount of 0.4 µmol/ml and apparent quantum yield of 1.3% at 450 nm.
R. P. Singh; O. S. Kushwaha
Abstract
Among all renewable sources, solar energy is the crucial zero emission renewable energy and the amount of solar energy impinging upon earth surface in one hour far exceeds the annual global energy demands. Polymer solar cells research exceeds crystalline silicon solar cells due to being inexpensive, ...
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Among all renewable sources, solar energy is the crucial zero emission renewable energy and the amount of solar energy impinging upon earth surface in one hour far exceeds the annual global energy demands. Polymer solar cells research exceeds crystalline silicon solar cells due to being inexpensive, light weight and processable into large area flexible devices. Polymer solar cells also possess high potential for power generation applications in comprehensive non-grid and grid modes. Moreover, the broad installment of polymer solar cells across the globe would certainly help to solve the problems associated with pollution, non-renewable resources, global warming and sustainability. Polymer solar cells being at present the hottest field of interdisciplinary research, there has been remarkable outcome in terms of efficiency of single-junction polymer solar cells, tandem solar cells, polymer-polymer solar cells, triple-junction polymer solar cells and solution-processed polymer solar cells. The present review briefly provides the latest breakthroughs and developments towards the efficiency and commercial aspects of various polymer solar cells.
M. Mzoughi; William. W. Anku; Samuel O. B. Oppong; Sudheesh K. Shukla; Eric S. Agorku; Penny P. Govender
Abstract
Purification of industrial wastewater from dyes receiving increasing attentions. The aim of the present manuscript was to fabricate graphene based nanocomposites using a homogeneous and facile approach. Co-precipitation method was used to synthesize zirconium oxide (ZrO2) and neodymium doped ZrO2-graphene ...
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Purification of industrial wastewater from dyes receiving increasing attentions. The aim of the present manuscript was to fabricate graphene based nanocomposites using a homogeneous and facile approach. Co-precipitation method was used to synthesize zirconium oxide (ZrO2) and neodymium doped ZrO2-graphene oxide (Nd-ZrO2-GO) nanocomposites with varying weight percent concentrations of neodymium to investigate the increasing photocatalytic activity. The Nd-ZrO2-GO catalysts were characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (SEM), and ultra violet-visible (UV-vis)-spectroscopy to evaluate their optical, morphological and structural properties respectively. The photocatalytic degradation potential of the nanocatalyst was assessed by the degradation of Eosin Y dye in aqueous solution under simulated solar light irradiation. The Nd-ZrO2-GO was observed to have higher photocatalytic degradation potential than the bare ZrO2. The most efficient photocatalyst for the degradation of Eosin Y dye was 0.3 % Nd-ZrO2-GO with about 80 % efficiency within 180 min and a Ka value of 4.19 x 10 -3 . Nd-ZrO2-GO catalyst would be considered as efficient photocatalyst to degrade the industrial dyes (Eosin Y) avoiding the dreary filtration steps.
Anuj Gulati; Narayan Agarwal;Sundeep K. Dhawan; Swati Varshney
Abstract
The paper aims to explore the utilization of industrial waste fly ash as a filler material into low density polyethylene (LDPE) polymer matrix with / without expanded graphite to optimize the electrostatic charge dissipative (ESD) properties as injection molded sheets. Homogeneous mixing of composite ...
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The paper aims to explore the utilization of industrial waste fly ash as a filler material into low density polyethylene (LDPE) polymer matrix with / without expanded graphite to optimize the electrostatic charge dissipative (ESD) properties as injection molded sheets. Homogeneous mixing of composite mixture has been carried out in a single screw extruder via melt blending and designed to sheet form by using an injection molding machine. The mechanical and thermal properties of the composite sheet depend on the formulation of composite material. The presence of fly ash particles and fly ash/ expanded graphite in the polymer system allows the composite sheet to acquire good mechanical and electrostatic charge dissipative properties. Static voltage decay rate and decay value measurement were carried out for LDPE and LDPE/fly ash/expanded graphite composite sheet. LDPE/fly ash/expanded graphite composite sheet having high percentage of expanded graphite showed good electrostatic charge dissipative properties. Further, structural analysis, surface morphology, thermal stability and mechanical properties have been explored by XRD, SEM, TGA and tensile testing.
R. K. Goyal; R. Sulakhe
Abstract
The preparation, electrical and thermal properties of nickel (Ni) particles filled poly(vinylidene fluoride) (PVDF) composites were discussed in this paper. The experimental density of the composites was close to that of theoretical density. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy ...
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The preparation, electrical and thermal properties of nickel (Ni) particles filled poly(vinylidene fluoride) (PVDF) composites were discussed in this paper. The experimental density of the composites was close to that of theoretical density. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that PVDF has primarily α-phase. The coefficient of thermal expansion of the composites decreased approximately 30 % compared to pure PVDF. The percolation threshold of the composite is about 5 vol% Ni, which is less than one-third of the value reported for metal filled polymer composites in the literature. The significantly lower percolation was attributed to the increased crystallinity and the better processing method which results in an easy formation of 3-dimensional network of Ni particles in the matrix, as confirmed by scanning electron microscopy (SEM). The electrical conductivity of these composites increased from 6.3×10 -13 S/cm to 2.6×10 -1 S/cm which is better and comparable than those of required for antistatic (10 -4 -10 -8 S/cm) and electromagnetic interference (EMI) shielding applications. The significant increase in electrical and thermal properties showed that these composites might be potential candidates for the EMI shielding and antistatic devices.
M. G. Kulthe;R. K. Goyal
Abstract
Polymer matrix composites filled with metals are widely studied for the applications in electrostatic dissipation (ESD) and electromagnetic interference (EMI) shielding. In view of this, the electrical conductivity and the microhardness of the polymer matrix composites based on poly(vinyl chloride) (PVC) ...
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Polymer matrix composites filled with metals are widely studied for the applications in electrostatic dissipation (ESD) and electromagnetic interference (EMI) shielding. In view of this, the electrical conductivity and the microhardness of the polymer matrix composites based on poly(vinyl chloride) (PVC) as matrix and copper (Cu) as reinforcement were determined. The composites were prepared using ball milling followed by hot pressing. Both constituents PVC and Cu were mixed together in a dry condition at room temperature for 12 h, 24 h and 36 h and then blended powder was hot pressed at 175 °C and 50 MPa. The Cu content was varied from 0 to 40 wt% (9.3 vol%) in the matrix. Optical microscope showed good dispersion of Cu particles in the matrix and the degree of Cu dispersion increased with increasing ball milling time. The electrical conductivity of the composites increased approximately six orders of magnitude for 9.3 vol% Cu composite. A percolation threshold was obtained at 3.7 vol% Cu. The microhardness increased by more than 18 % compared to the pure matrix. For a given loading of Cu, the electrical conductivity and the microhardness of the composites increased with increasing ball-milling time. This was attributed to the better and uniform dispersion of the Cu particles in the matrix at higher ball milling time.
R. K. Goyal; J.N. Sahu
Abstract
High performance polymer nanocomposites based on poly(etheretherketone) (PEEK) as matrix and modified clay as reinforcement were fabricated using hot pressing at 380 °C and 45 MPa. The clay was varied from 0 to 5 wt%. Nanocomposites were characterized by X-ray diffraction (XRD), Vickers hardness ...
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High performance polymer nanocomposites based on poly(etheretherketone) (PEEK) as matrix and modified clay as reinforcement were fabricated using hot pressing at 380 °C and 45 MPa. The clay was varied from 0 to 5 wt%. Nanocomposites were characterized by X-ray diffraction (XRD), Vickers hardness tester, high resistivity meter, and impedance analyzer to get information about morphology, microhardness, electrical conductivity and dielectric properties of nanocomposites, respectively. The experimental density was very close to the theoretical density. XRD showed exfoliation of clay up to 3 wt% and intercalation for 5 wt% nanocomposite. The water absorption decreased by 38 % at 1 wt% clay content. The microhardness increased up to 12 % for 2 wt% clay nanocomposite. Electrical conductivity was increased two orders of magnitude higher than pure PEEK. Dielectric constant was increased slightly with increasing clay content. The significant improvement in properties at lower clay loading might be attributed to the exfoliation of clay in the matrix.
Rajendra Kumar Goyal;Amol Kadam
Abstract
Electrical properties of graphite flake (GF) filled polyphenylene sulphide (PPS) composites prepared by hot pressing was investigated to be used for electromagnetic interference (EMI) shielding applications. Composites exhibited an electrical conductivity percolation threshold of 5 wt%. The electrical ...
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Electrical properties of graphite flake (GF) filled polyphenylene sulphide (PPS) composites prepared by hot pressing was investigated to be used for electromagnetic interference (EMI) shielding applications. Composites exhibited an electrical conductivity percolation threshold of 5 wt%. The electrical conductivity of composites was increased fourteen orders of magnitude higher than that of pure PPS. The dielectric constants and dissipation factor of composites were measured in a frequency range of 100 KHz to 15 MHz. The dielectric constant of the composites increased several orders of magnitude and showed a strong dependence on frequencies. For example, dielectric constant of 8 wt% composite measured at 1 MHz was increased by five orders of magnitude compared to pure PPS. Similarly, dissipation factor was increased significantly. Scanning electron microscopy showed 3-dimensional conducting network of GF across the PPS matrix. Significant improvement in electrical properties shows that these composites may be useful for EMI shielding particularly at high temperature applications.
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