Energy harvesting performance of an EDLC power generator based on pure water and glycerol mixture: analytical modeling and experimental validation

AbstractA liquid droplet oscillating between two plane electrodes was visualized, and the electrical power generation based on the reverse-electrowetting-on-dielectric (REWOD) phenomenon was measured. For the upper plate, a hydrophobic surface treated by PTFE was used, and the lower plate was tested using the hydrophilic surface properties of ITO glass. To analyze the dynamic behavior of an oscillating liquid bridge, a modeling study was carried out using the phase field method based on the finite element method. The dynamic contact angle of the oscillating liquid bridge was modeled based on advancing and receding contact angles. The variable interfacial areas between the liquid and solid surfaces were calculated and agreed well with the experimental results within a 10% error band. Furthermore, experimental and analytical studies were carried out to examine the REWOD energy harvesting characteristics of the glycerol-water mixtures in various concentrations. As a result, the peak voltage output was obtained at a specific concentration of the glycerol mixture, and the power density of the oscillating liquid bridge at this point was up to 2.23 times higher than that of pure water.

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Capillary-Based Liquid Micro/Nano Deposition

Volume 6: Fluids and Thermal Systems; Advances for Process Industries, Parts A and B ◽

10.1115/imece2011-62939 ◽

2011 ◽

Author(s):

Artur Lutfurakhmanov ◽

Yechun Wang ◽

Douglas L. Schulz ◽

Iskander S. Akhatov

Keyword(s):

Liquid Bridge ◽

Liquid Droplet ◽

Applied Pressure ◽

Deposition Process ◽

Contact Angles ◽

Liquid Pressure ◽

Bridge Formation ◽

Non Invasive ◽

Two Parameters ◽

Nano Imprint

Micro/Nanolithography is a creation of micro/nano features on the substrate. Several lithography techniques have been recently developed, including dip-pen nanolithography, nano-imprint lithography, electron-beam lithography, and photolithography. However, all these techniques possess some limitations because of a direct contact with the substrate. This paper proposes a new method that is non-invasive both to the substrate and to the writing tip. The method is based on hollow capillary filled with liquid to be deposited. The application of pressure from one side of capillary causes the liquid meniscus to form at the capillary outlet. Touching the substrate with the meniscus only leads to the liquid bridge formation between the capillary and the substrate. Withdrawing the capillary away from the substrate causes deposition of liquid droplet on the substrate. Theoretical modeling reveals two possible regimes of the liquid bridge formation: stable — “good” bridge and unstable — “bad” bridge. Liquid bridge stability map was created based on two parameters: liquid pressure and the capillary-substrate distance. It was found that the main parameter responsible for the deposition process is the applied pressure. Three pressure ranges were identified with different deposition scenarios. The influence of liquid-capillary and liquid-substrate equilibrium contact angles along with the capillary wall thickness on the liquid bridge stability is discussed.

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Electrode and electrolyte configurations for low frequency motion energy harvesting based on reverse electrowetting

Scientific Reports ◽

10.1038/s41598-021-84414-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Pashupati R. Adhikari ◽

Nishat T. Tasneem ◽

Russell C. Reid ◽

Ifana Mahbub

Keyword(s):

Energy Harvesting ◽

Bias Voltage ◽

Energy Harvester ◽

Superior Performance ◽

Maximum Output ◽

Electrowetting On Dielectric ◽

External Bias ◽

Motion Energy ◽

Ac Current ◽

Self Powered

AbstractIncreasing demand for self-powered wearable sensors has spurred an urgent need to develop energy harvesting systems that can reliably and sufficiently power these devices. Within the last decade, reverse electrowetting-on-dielectric (REWOD)-based mechanical motion energy harvesting has been developed, where an electrolyte is modulated (repeatedly squeezed) between two dissimilar electrodes under an externally applied mechanical force to generate an AC current. In this work, we explored various combinations of electrolyte concentrations, dielectrics, and dielectric thicknesses to generate maximum output power employing REWOD energy harvester. With the objective of implementing a fully self-powered wearable sensor, a “zero applied-bias-voltage” approach was adopted. Three different concentrations of sodium chloride aqueous solutions (NaCl-0.1 M, NaCl-0.5 M, and NaCl-1.0 M) were used as electrolytes. Likewise, electrodes were fabricated with three different dielectric thicknesses (100 nm, 150 nm, and 200 nm) of Al2O3 and SiO2 with an additional layer of CYTOP for surface hydrophobicity. The REWOD energy harvester and its electrode–electrolyte layers were modeled using lumped components that include a resistor, a capacitor, and a current source representing the harvester. Without using any external bias voltage, AC current generation with a power density of 53.3 nW/cm2 was demonstrated at an external excitation frequency of 3 Hz with an optimal external load. The experimental results were analytically verified using the derived theoretical model. Superior performance of the harvester in terms of the figure-of-merit comparing previously reported works is demonstrated. The novelty of this work lies in the combination of an analytical modeling method and experimental validation that together can be used to increase the REWOD harvested power extensively without requiring any external bias voltage.

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Design and Analysis of a While-Drilling Energy-Harvesting Device Based on Piezoelectric Effect

Energies ◽

10.3390/en14051266 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1266

Author(s):

Jun Zheng ◽

Bin Dou ◽

Zilong Li ◽

Tianyu Wu ◽

Hong Tian ◽

...

Keyword(s):

Energy Harvesting ◽

Piezoelectric Material ◽

Longitudinal Vibration ◽

Coupling Model ◽

Energy Harvest ◽

Peak Voltage ◽

Piezoelectric Patch ◽

Theoretical Support ◽

Piezoelectric Coupling ◽

Continuous Power

A while-drilling energy harvesting device is designed in this paper to recovery energy along with the longitudinal vibration of the drill pipes, aiming to serve as a continuous power supply for downhole instruments during the drilling procedure. Radial size of the energy harvesting device is determined through the drilling engineering field experience and geological survey reports. A piezoelectric coupling model based on the selected piezoelectric material was established via COMSOL Multiphysics numerical simulation. The forced vibration was analyzed to determine the piezoelectric patch length range and their best installation positions. Modal analysis and frequency response research indicate that the natural frequency of the piezoelectric cantilever beam increased monotonously with the increase of the piezoelectric patch’ thickness before reaching an inflection point. Moreover, the simulation results imply that the peak voltage of the harvested energy varied in a regional manner with the increase of the piezoelectric patches. When the thickness of the piezoelectric patches was 1.2–1.4 mm, the designed device gained the best energy harvest performance with a peak voltage of 15–40 V. Works in this paper provide theoretical support and design reference for the application of the piezoelectric material in the drilling field.

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P4VP Modified Zwitterionic Polymer for the Preparation of Antifouling Functionalized Surfaces

Nanomaterials ◽

10.3390/nano9050706 ◽

2019 ◽

Vol 9 (5) ◽

pp. 706 ◽

Cited By ~ 5

Author(s):

Chaoqun Wu ◽

Yudan Zhou ◽

Haitao Wang ◽

Jianhua Hu

Keyword(s):

Photoelectron Spectroscopy ◽

Cell Attachment ◽

Raft Polymerization ◽

Polymer Brush ◽

Contact Angles ◽

Polymerization Process ◽

Water Contact ◽

Zwitterionic Polymers ◽

Ito Glass ◽

Zwitterionic Polymer

Zwitterionic polymers are suitable for replacing poly(ethylene glycol) (PEG) polymers because of their better antifouling properties, but zwitterionic polymers have poor mechanical properties, strong water absorption, and their homopolymers should not be used directly. To solve these problems, a reversible-addition fragmentation chain transfer (RAFT) polymerization process was used to prepare copolymers comprised of zwitterionic side chains that were attached to an ITO glass substrate using spin-casting. The presence of 4-vinylpyridine (4VP) and zwitterion chains on these polymer-coated ITO surfaces was confirmed using 1H NMR, FTIR, and GPC analyses, with successful surface functionalization confirmed using water contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) studies. Changes in water contact angles and C/O ratios (XPS) analysis demonstrated that the functionalization of these polymers with β-propiolactone resulted in hydrophilic mixed 4VP/zwitterionic polymers. Protein adsorption and cell attachment assays were used to optimize the ratio of the zwitterionic component to maximize the antifouling properties of the polymer brush surface. This work demonstrated that the antifouling surface coatings could be readily prepared using a “P4VP-modified” method, that is, the functionality of P4VP to modify the prepared zwitterionic polymer. We believe these materials are likely to be useful for the preparation of biomaterials for biosensing and diagnostic applications.

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Flexible Carbon-Based Nanogenerators

MRS Proceedings ◽

10.1557/opl.2015.640 ◽

2015 ◽

Vol 1782 ◽

pp. 1-8

Author(s):

Ning-Qin Deng ◽

He Tian ◽

Qing-Tang Xue ◽

Zhe Wang ◽

Hai-Ming Zhao ◽

...

Keyword(s):

Carbon Nanotubes ◽

Graphene Oxide ◽

Energy Harvesting ◽

Zno Nanoparticles ◽

Output Voltage ◽

Multiwall Carbon Nanotubes ◽

The Other ◽

Peak Voltage ◽

Energy Depletion ◽

Multiwall Carbon

ABSTRACTNanogenerators (NGs) have great potential to solve the problems of energy depletion and environmental pollution. Here, two types of flexible nanogenerators (FNGs) based on graphene oxide (GO) and multiwall carbon nanotubes (MW-CNTs) are presented. The peak output voltage and current of GO based FNG reached up to 2 V and 30 nA, respectively, under 15 N force at 1 Hz. Moreover, the output voltage could be improved to 34.4 V when the frequency was increased to 10 Hz. It was also found the output voltage increased from 0.1 V to 2.0 V using a released GO structure. The other FNG was made by MW-CNTs mixed with ZnO nanoparticles (NPs). Its output voltage and power reached up to 7.5 V and 18.75 mW, respectively, which is much larger than that of bare ZnO based FNG. Furthermore, a peak voltage of 30 V could be gained by stamping one’s foot on the FNG. Finally, a modified NG was fabricated using four springs and two flexible layers. As a result, the voltage and power reached up to 9 V and 27mW, respectively. These works may bring out broad applications in energy harvesting.

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Sessile droplets on deformable substrates

10.20944/preprints201809.0416.v1 ◽

2018 ◽

Author(s):

Gulraiz Ahmed ◽

Nektaria Koursari ◽

Anna Trybala ◽

Victor M. Starov

Keyword(s):

Liquid Droplet ◽

Contact Angles ◽

Surface Forces ◽

Interfacial Behavior ◽

Equilibrium Conditions ◽

The Past ◽

Technological Advances ◽

Three Phase ◽

Significant Interest ◽

Receding Contact

Wetting of deformable substrates has gained significant interest over the past decade due to its extensive applications and uses. This interest has developed due to technological advances which are able to capture interfacial behavior taking place when a liquid droplet is placed on a deformable substrate. Researchers have developed different theories to explain processes taking place in the process of wetting of deformable/soft substrates. For the scope of this review, we will consider the fluid to be Newtonian, partially wetting, and surface forces are incorporated with the help of disjoining/conjoining pressure acting in the vicinity of the apparent, three-phase contact line. The following subjects are briefly reviewed: (i) Equilibrium of droplets on soft substrates. It is shown that properties of the disjoining/conjoining pressure isotherm and properties of the deformable substrate determine both the shape of the liquid droplet and deformation of the substrate; (ii) Equilibrium conditions of droplets on deformable substrates. It is shown that for a droplet to be at equilibrium on a deformable substrate under consideration, Jacobi’s sufficient condition is satisfied; (iii) Hysteresis of contact angle of sessile droplets on deformable substrates. It is shown that as the elasticity of the deformable substrate is increased, both advancing and receding contact angles are reduced.

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Molecular Dynamics Simulation of Wetting Behavior: Contact Angle Dependency on Water Potential Models

ICS Physical Chemistry ◽

10.34311/icspc.2021.1.1.10 ◽

2021 ◽

Vol 1 (1) ◽

pp. 10

Author(s):

Lukman Hakim ◽

Irsandi Dwi Oka Kurniawan ◽

Ellya Indahyanti ◽

Irwansyah Putra Pradana

Keyword(s):

Molecular Dynamics ◽

Contact Angle ◽

Liquid Droplet ◽

Center Of Mass ◽

Contact Angles ◽

Surface Wettability ◽

Dynamics Simulation ◽

Potential Models ◽

Surface Hydrophilicity ◽

Dynamics Simulations

The underlying principle of surface wettability has obtained great attentions for the development of novel functional surfaces. Molecular dynamics simulations has been widely utilized to obtain molecular-level details of surface wettability that is commonly quantified in term of contact angle of a liquid droplet on the surface. In this work, the sensitivity of contact angle calculation at various degrees of surface hydrophilicity to the adopted potential models of water: SPC/E, TIP4P, and TIP5P, is investigated. The simulation cell consists of a water droplet on a structureless surface whose hydrophilicity is modified by introducing a scaling factor to the water-surface interaction parameter. The simulation shows that the differences in contact angle described by the potential models are systematic and become more visible with the increase of the surface hydrophilicity. An alternative method to compute a contact angle based on the height of center-of-mass of the droplet is also evaluated, and the resulting contact angles are generally larger than those determined from the liquid-gas interfacial line.

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Novel Flexible Triboelectric Nanogenerator based on Metallized Porous PDMS and Parylene C

Energies ◽

10.3390/en13071625 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1625 ◽

Cited By ~ 2

Author(s):

Massimo Mariello ◽

Elisa Scarpa ◽

Luciana Algieri ◽

Francesco Guido ◽

Vincenzo Mariano Mastronardi ◽

...

Keyword(s):

Energy Harvesting ◽

Power Density ◽

Open Circuit ◽

Triboelectric Nanogenerator ◽

Steam Curing ◽

Density Peak ◽

Peak Voltage ◽

Parylene C ◽

Pdms Surface ◽

Wide Range

Triboelectric nanogenerators (TENGs) have recently become a powerful technology for energy harvesting and self-powered sensor networks. One of their main advantages is the possibility to employ a wide range of materials, especially for fabricating inexpensive and easy-to-use devices. This paper reports the fabrication and preliminary characterization of a novel flexible triboelectric nanogenerator which could be employed for driving future low power consumption wearable devices. The proposed TENG is a single-electrode device operating in contact-separation mode for applications in low-frequency energy harvesting from intermittent tapping loads involving the human body, such as finger or hand tapping. The novelty of the device lies in the choice of materials: it is based on a combination of a polysiloxane elastomer and a poly (para-xylylene). In particular, the TENG is composed, sequentially, of a poly (dimethylsiloxane) (PDMS) substrate which was made porous and rough with a steam-curing step; then, a metallization layer with titanium and gold, deposited on the PDMS surface with an optimal substrate–electrode adhesion. Finally, the metallized structure was coated with a thin film of parylene C serving as friction layer. This material provides excellent conformability and high charge-retaining capability, playing a crucial role in the triboelectric process; it also makes the device suitable for employment in harsh, wet environments owing to its inertness and barrier properties. Preliminary performance tests were conducted by measuring the open-circuit voltage and power density under finger tapping (~2 N) at ~5 Hz. The device exhibited a peak-to-peak voltage of 1.6 V and power density peak of 2.24 mW/m2 at ~0.4 MΩ. The proposed TENG demonstrated ease of process, simplicity, cost-effectiveness, and flexibility.

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Designing Splicing Digital Microfluidics Chips Based on Polytetrafluoroethylene Membrane

Micromachines ◽

10.3390/mi11121067 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1067

Author(s):

Haoqiang Feng ◽

Zichuan Yi ◽

Ruizhi Yang ◽

Xiaofeng Qin ◽

Shitao Shen ◽

...

Keyword(s):

Indium Tin Oxide ◽

Silicone Oil ◽

Digital Microfluidics ◽

Simultaneous Detection ◽

Driving Voltage ◽

Electrowetting On Dielectric ◽

Practical Applications ◽

Multiple Components ◽

Ito Glass ◽

Off Time

As a laboratory-on-a-chip application tool, digital microfluidics (DMF) technology is widely used in DNA-based applications, clinical diagnosis, chemical synthesis, and other fields. Additional components (such as heaters, centrifuges, mixers, etc.) are required in practical applications on DMF devices. In this paper, a DMF chip interconnection method based on electrowetting-on-dielectric (EWOD) was proposed. An open modified slippery liquid-infused porous surface (SLIPS) membrane was used as the dielectric-hydrophobic layer material, which consisted of polytetrafluoroethylene (PTFE) membrane and silicone oil. Indium tin oxide (ITO) glass was used to manufacture the DMF chip. In order to test the relationship between the splicing gap and droplet moving, the effect of the different electrodes on/off time on the minimum driving voltage when the droplet crossed a splicing gap was investigated. Then, the effects of splicing gaps of different widths, splicing heights, and electrode misalignments were investigated, respectively. The experimental results showed that a driving voltage of 119 V was required for a droplet to cross a splicing gap width of 300 μm when the droplet volume was 10 μL and the electrode on/off time was 600 ms. At the same time, the droplet could climb a height difference of 150 μm with 145 V, and 141 V was required when the electrode misalignment was 1000 μm. Finally, the minimum voltage was not obviously changed, when the same volume droplet with different aqueous solutions crossed the splicing gap, and the droplet could cross different chip types. These splicing solutions show high potential for simultaneous detection of multiple components in human body fluids.

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Solvothermal Preparation of Nano-Sized CaWO4 Particles

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.1265 ◽

2007 ◽

Vol 124-126 ◽

pp. 1265-1268 ◽

Cited By ~ 3

Author(s):

Sulawan Kaowphong ◽

Titipun Thongtem ◽

Somchai Thongtem

Keyword(s):

Pure Water ◽

Solvothermal Reaction ◽

Hrtem Image ◽

Scheelite Structure ◽

Glycerol Water ◽

Calcium Salts ◽

Solvothermal Preparation

CaWO4 was prepared by solvothermal reaction of Na2WO4.2H2O and calcium salts (CaCl2.2H2O, Ca(NO3)2.4H2O and Ca(CH3COO)2) in solvent containing a variety of glycerol/water ratios at 160 oC for 6 h. By using XRD, SEM, TEM and ED, the products compose of nano-sized CaWO4 particles with scheelite structure but different morphologies. Interplanar spaces between (101) planes were determined from HRTEM image, ED patterns and XRD spectra are 0.424, 0.474 and 0.476 nm, respectively. Luminescent intensities of the products prepared in pure water are the highest and their central peaks are the same at 444 nm. In addition, Ca, W and O were detected using EDX.

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