Energy harvesting using air bubbles on hydrophobic surfaces containing embedded charges

Wijewardhana, K. Rohana; Shen, Tong; Song, Jang‐Kun

doi:10.1016/j.apenergy.2017.08.211

Cited by 36 publications

(22 citation statements)

References 29 publications

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“…The energy harvester with superhydrophobic coating adopted liquid itself as a triboelectric material, and show the spotlight to overcome the inevitable friction wear between two solid materials in conventional TENGs (triboelectric nanogenerator) [ 15 , 16 ]. Jihoon Chung et al developed a sprayed-on TENG using a commercial hydrophobic spray that can easily create a superhydrophobic surface.…”

Section: Introductionmentioning

confidence: 99%

Triboelectric Energy Harvesting of the Superhydrophobic Coating from Dropping Water

Niu

Tian

et al. 2020

Polymers

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In this paper, the superhydrophobic coating was prepared by spraying the composites of fluorocarbon emulsion and nanosized silica on the conductive glass sheet for the triboelectric energy harvesting from water droplets. The low surface energy of fluorine in the fluorocarbon emulsion and nanosilica renders the coating with the static contact angle and sliding angle of 156.2° and 6.74°, respectively. The conductive aluminum tape was attached on the surface of the superhydrophobic coating to complete the circuit constituted with the aluminum electrode, charged superhydrophobic coating, and the conductive glass sheet. During the contact electrification with the bouncing water droplet, the superhydrophobic coating with the aluminum electrode can obtain the electric energy with an open-circuit voltage of 20 V and short-circuit current of 4.5 μA, respectively. While the control device only produced an open-circuit voltage of 0.2 V. The generated power by one drop was enough to light up 16 commercial LEDs. Results demonstrate that the fluorocarbon/silica composite superhydrophobic coating is potentially a strong candidate for scavenging energy in sliding mode from raindrops.

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Section: Introductionmentioning

confidence: 99%

Triboelectric Energy Harvesting of the Superhydrophobic Coating from Dropping Water

Niu

Tian

et al. 2020

Polymers

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“…Lab-on-a-chip devices have been using EWOD digital microfluidics for more than a decade to manipulate individual droplets (Fair 2007;Samiei et al 2016) and to control liquid in channels or pores (Prins et al 2001). EWOD is also used in other applications: liquid lenses (Mishra et al 2014(Mishra et al , 2016, screen displays (Charipar et al 2015;You and Steckl 2010), power conversion from electric to hydraulic (Kedzierski et al 2016) and mechanical to electric (Krupenkin and Taylor 2011;Wijewardhana et al 2017), liquid-metal antennas (Diebold et al 2017), and active surface roughness control (Merrill et al 2014;Reid et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Stick–slip behavior during electrowetting-on-dielectric: polarization and substrate effects

Reid

Merrill

Thomas

2020

Microfluid Nanofluid

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A novel triple-line stick–slip behavior, manifested by “sawtooth oscillations” of the contact angle (CA), was observed during sessile droplet advance by electrowetting-on-dielectric (EWOD) for DC voltages and during droplet retreat for AC voltages. The onset of stick–slip occurred on polished substrate surfaces when the applied potential approached the EWOD saturation voltage and at lower voltages on rougher surfaces. Stick–slip was reduced at higher AC frequencies (> 1 kHz), not significantly influenced by pH or voltage polarity and did not occur with AC polarization on substrates with a Parylene coating but no hydrophobic top-layer. The different triple-line pinning behaviors under DC and AC polarization are shown to be consistent with heterogeneous wetting associated with immobilization of charged species—referred to as charge trapping—near the triple-line at saturation. These experiments and insights offer a new approach for understanding and addressing EWOD device limitations related to CA saturation and charged species trapping leading to improved performance in micro-/nanofluidic pumps, digital microfluidic chips, and electret devices. Graphical Abstract

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Section: Extended Abstractmentioning

confidence: 99%

“…Energy conversion efficiency of BMAT is remarkably higher compared to WMAT. WMAT converts about seven time larger energy than water droplet due to the differences in contact area, moving speed, deformation of the bubble and multiple peak outputs from a single bubble [6].Surface charge density on the hydrophobic surface is a critical factor for energy conversion. In this experiment we increased the surface charge density by exposing the surface to argon plasma.…”

mentioning

confidence: 99%

Electrical Energy form Rising Air Bubbles

Wijewardhana¹,

Shahzad²,

Jayaweera³

et al. 2018

International Conference of Energy Harvesting, Storage, and Transfer

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Extended AbstractTechnologies to harvest electrical energy from waste micro mechanical energy sources have gained considerable attention due to self-powered technology. Different energy sources and energy conversion methods are essential not only for large scale but also for micro/nano scale for self-powered sensors, wearable devices and wireless networks. A few methods have been developed in last decades for conversion of ambient energy to electrical energy such as piezoelectric, photovoltaics and triboelectric methods [1][2][3]. Moreover, contact electrification of liquid-solid interface has become a promising energy harvesting method due to its simple fabrication steps, durability and capability to operate without external bias energy.In this study, we demonstrate a rising air bubble converts its energy to electrical energy while rising beneath a hydrophobic strip shaped electrodes. The two electrode system under water can be represented as two serially connected electrical double layer (EDL) capacitors [4]. Adsorption and desorption of the ions take place when a bubble rises beneath the hydrophobic surface due to formation of three phase contact line. As a result, EDL capacitors asymmetrically charge and discharge producing voltage deference between two electrodes.We compared the output energy of this bubble motion active transducer (BMAT) with the similar system using a descending water droplet called water motion active transducer (WMAT) [5]. Energy conversion efficiency of BMAT is remarkably higher compared to WMAT. WMAT converts about seven time larger energy than water droplet due to the differences in contact area, moving speed, deformation of the bubble and multiple peak outputs from a single bubble [6].Surface charge density on the hydrophobic surface is a critical factor for energy conversion. In this experiment we increased the surface charge density by exposing the surface to argon plasma. Enhancement of surface charge density takes place due to braking bonds and formation of free radicals on the surface. This is confirmed by measuring the water contact angle and electrostatic potential on the hydrophobic surface. The contact angle decreases from the initial value of 119.7° to 108.2° and the surface potential from -2.4 V to -4.3 V. After the plasma treatment, BMAT converted 70 nJ from a single air bubble, which is about 18 times higher than the fresh surface.Finally, we demonstrated the multi-electrodes based BMAT for effective harvesting of energy from rising air bubbles. Multiple current outputs produced by a single air bubble results in higher energy conversion efficiencies. The output energy strongly depends on the way of end connection of the multi-electrodes system. Interdigital electrodes (IDEs) based BMAT and individual rectified multi-electrodes (IRMEs) based BMAT are remarkably different in terms of their energy output. Even though both the systems produce multiple current outputs, energy converted by IDEs based BMAT decreases with the increasing the number of electrodes due to the effec...

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Energy harvesting using air bubbles on hydrophobic surfaces containing embedded charges

Cited by 36 publications

References 29 publications

Triboelectric Energy Harvesting of the Superhydrophobic Coating from Dropping Water

Triboelectric Energy Harvesting of the Superhydrophobic Coating from Dropping Water

Stick–slip behavior during electrowetting-on-dielectric: polarization and substrate effects

Electrical Energy form Rising Air Bubbles

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