scholarly journals Generating Electricity from Natural Evaporation Using PVDF Thin Films Incorporating Nanocomposite Materials

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 585
Author(s):  
Ariel Ma ◽  
Jian Yu ◽  
William Uspal
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Capillary Flow ◽  
Short Circuit ◽  
Current Source ◽  
Nanocomposite Materials ◽  
The Other ◽  
Pvdf Film ◽  
Ambient Conditions

Natural evaporation has recently come under consideration as a viable source of renewable energy. Demonstrations of the validity of the concept have been reported for devices incorporating carbon-based nanocomposite materials. In this study, we investigated the possibility of using polymer thin films to generate electricity from natural evaporation. We considered a polymeric system based on polyvinylidene fluoride (PVDF). Porous PVDF films were created by incorporating a variety of nanocomposite materials into the polymer structure through a simple mixing procedure. Three nanocomposite materials were considered: carbon nanotubes, graphene oxide, and silica. The evaporation-induced electricity generation was confirmed experimentally under various ambient conditions. Among the nanocomposite materials considered, mesoporous silica (SBA-15) was found to outperform the other two materials in terms of open-circuit voltage, and graphene oxide generated the highest short-circuit current. It was found that the nanocomposite material content in the PVDF film plays an important role: on the one hand, if particles are too few in number, the number of channels will be insufficient to support a strong capillary flow; on the other hand, an excessive number of particles will suppress the flow due to excessive water absorption underneath the surface. We show that the device can be modeled as a simple circuit powered by a current source with excellent agreement between the theoretical predictions and experimental data.

scholarly journals Preparation of PVDF-CNT composite

2021 ◽  
Vol 270 ◽  
pp. 01012
Author(s):  
Denis Misiurev ◽  
Ştefan Ţălu ◽  
Rashid Dallaev ◽  
Dinara Sobola ◽  
Mariya Goncharova
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Metal Nanoparticles ◽  
Polyvinylidene Fluoride ◽  
Mechanical Stability ◽  
Ceramic Particles ◽  
Piezoelectric Polymers ◽  
Chemical Inertness ◽  
High Flexibility

Limitations of ceramic piezomaterials (brittleness, toxicity of lead-containing samples, difficulties of complicated shapes preparations, etc.) call for the research in the field of piezoelectric polymers. One of them is polyvinylidene fluoride (PVDF). It could be prepared in various forms: thin films, bulk samples, fibers. PVDF fibers attract the most attention because of high flexibility, lightweight, mechanical stability, chemical inertness. Properties of PVDF fibers can be tuned using dopant material: ceramic particles, metal nanoparticles, graphite materials as graphene oxide or carbon nanotubes (CNT).

Enhanced piezo-electric property induced in graphene oxide/polyvinylidene fluoride composite flexible thin films

2017 ◽  
Vol 39 (11) ◽  
pp. 4205-4216 ◽  
Author(s):  
Ritamay Bhunia ◽  
Rajkumar Dey ◽  
Shirsendu Das ◽  
Shamima Hussain ◽  
Radhaballav Bhar ◽  
...  
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Electric Property ◽  
Piezo Electric

Studies of the effect of temperature on charge accumulation in PVDF-PMMA double-layered thin films based on depolarization current measurements

2021 ◽  
pp. 009524432199640
Author(s):  
Pooja Saxena ◽  
Prashant Shukla
Keyword(s):  
Thin Films ◽  
Polyvinylidene Fluoride ◽  
Short Circuit ◽  
Charge Trapping ◽  
Opposite Polarity ◽  
Air Gap ◽  
Excess Charge ◽  
Polarization Current ◽  
Surface Charges ◽  
Depolarization Current

In this paper, we have reported the interpretation of air gap (Thermally Stimulated Depolarization Current) of surface charges in PVDF-PMMA (Polyvinylidene fluoride (PVDF)–Polymethyl methacrylate (PMMA)) double-layered polymer thin films whose decay could not be observed in metalized electrets with short-circuit TSDC. Since short-circuit TSDC is caused by the relaxations of homo- and hetero-charge flow in one direction and thus makes it difficult to identify, separate, and characterize its components, therefore, an air gap was introduced to the short-circuit TSDC technique to carry out air-gap TSDC. This technique enables one to observe the orientation of dipoles, excess charge decay by ohmic conduction, and decay of surface charge. When a dielectric is charged by an application of an external field, two charges with opposite polarity and different nature can be found. Air-gap TSDC’s of double-layer samples revealed the presence of homo charge; charges trapped at the surface are due to dissipation of space charges thus, the depolarization current is observed to have the same polarity as that of the polarization current. Hetero-charge persists at high temperatures due to the bulk polarization formed because of the electric field created by the homo-charge. Hence, the depolarization current observed in the present study was observed to be of opposite polarity as that of polarization current. The above discussed polymeric layered structure was found to be a source of charge trapping which was identified and confirmed by various calculated parameters.

scholarly journals Rapid synchronized fabrication of vascularized thermosets and composites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mayank Garg ◽  
Jia En Aw ◽  
Xiang Zhang ◽  
Polette J. Centellas ◽  
Leon M. Dean ◽  
...  
Keyword(s):  
Large Scale ◽  
Capillary Flow ◽  
External Heat ◽  
Frontal Polymerization ◽  
Self Healing ◽  
Vascular Networks ◽  
Ambient Conditions ◽  
External Energy ◽  
Imaging Phantoms ◽  
Vascular Structures

AbstractBioinspired vascular networks transport heat and mass in hydrogels, microfluidic devices, self-healing and self-cooling structures, filters, and flow batteries. Lengthy, multistep fabrication processes involving solvents, external heat, and vacuum hinder large-scale application of vascular networks in structural materials. Here, we report the rapid (seconds to minutes), scalable, and synchronized fabrication of vascular thermosets and fiber-reinforced composites under ambient conditions. The exothermic frontal polymerization (FP) of a liquid or gelled resin facilitates coordinated depolymerization of an embedded sacrificial template to create host structures with high-fidelity interconnected microchannels. The chemical energy released during matrix polymerization eliminates the need for a sustained external heat source and greatly reduces external energy consumption for processing. Programming the rate of depolymerization of the sacrificial thermoplastic to match the kinetics of FP has the potential to significantly expedite the fabrication of vascular structures with extended lifetimes, microreactors, and imaging phantoms for understanding capillary flow in biological systems.

scholarly journals X-ray Photoelectron Spectroscopy Analysis of Chitosan–Graphene Oxide-Based Composite Thin Films for Potential Optical Sensing Applications

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 478
Author(s):  
Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽  
Yap Wing Fen ◽  
Silvan Saleviter ◽  
Narong Chanlek ◽  
Hideki Nakajima ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Functional Group ◽  
Optical Sensing ◽  
Composite Thin Films ◽  
Cobalt Ions ◽  
X Ray ◽  
Sensing Applications

In this study, X-ray photoelectron spectroscopy (XPS) was used to study chitosan–graphene oxide (chitosan–GO) incorporated with 4-(2-pyridylazo)resorcinol (PAR) and cadmium sulfide quantum dot (CdS QD) composite thin films for the potential optical sensing of cobalt ions (Co2+). From the XPS results, it was confirmed that carbon, oxygen, and nitrogen elements existed on the PAR–chitosan–GO thin film, while for CdS QD–chitosan–GO, the existence of carbon, oxygen, cadmium, nitrogen, and sulfur were confirmed. Further deconvolution of each element using the Gaussian–Lorentzian curve fitting program revealed the sub-peak component of each element and hence the corresponding functional group was identified. Next, investigation using surface plasmon resonance (SPR) optical sensor proved that both chitosan–GO-based thin films were able to detect Co2+ as low as 0.01 ppm for both composite thin films, while the PAR had the higher binding affinity. The interaction of the Co2+ with the thin films was characterized again using XPS to confirm the functional group involved during the reaction. The XPS results proved that primary amino in the PAR–chitosan–GO thin film contributed more important role for the reaction with Co2+, as in agreement with the SPR results.

scholarly journals Graphene oxide-based rechargeable respiratory masks

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Stelbin Peter Figerez ◽  
Sudeshna Patra ◽  
G Rajalakshmi ◽  
Tharangattu N Narayanan
Keyword(s):  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Occupational Safety ◽  
Low Cost ◽  
Triboelectric Nanogenerator ◽  
Layer System ◽  
Retention Capacity ◽  
Simple Modification ◽  
Nonwoven Fabrics ◽  
Mask Design

Abstract Respiratory masks having similar standards of ‘N95’, defined by the US National Institute for Occupational Safety and Health, will be highly sought after, post the current COVID-19 pandemic. Here, such a low-cost (∼$1/mask) mask design having electrostatic rechargeability and filtration efficiency of >95% with a quality factor of ∼20 kPa−1 is demonstrated. This filtration efficacy is for particles of size 300 nm. The tri-layer mask, named PPDFGO tri, contains nylon, modified polypropylene (PPY), and cotton nonwoven fabrics as three layers. The melt-spun PPY, available in a conventional N95 mask, modified with graphene oxide and polyvinylidene fluoride mixture containing paste using a simple solution casting method acts as active filtration layer. The efficacy of this tri-layer system toward triboelectric rechargeability using small mechanical agitations is demonstrated here. These triboelectric nanogenerator (TENG)-assisted membranes have high electrostatic charge retention capacity (∼1 nC/cm2 after 5 days in ambient condition) and high rechargeability even in very humid conditions (>80% RH). A simple but robust permeability measurement set up is also constructed to test these TENG-based membranes, where a flow rate of 30–35 L/min is maintained during the testing. Such a simple modification to the existing mask designs enabling their rechargeability via external mechanical disturbances, with enhanced usability for single use as well as for reuse with decontantamination, will be highly beneficial in the realm of indispensable personal protective equipment.

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