Harvesting water surface energy: self-jumping nanostructured hydrophobic metals.
Ontology highlight
ABSTRACT:
SUBMITTER: Tsai JY
PROVIDER: S-EPMC8258681 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Humans face a severe shortage of fresh water due to economic growth, climate change, overpopulation, and overutilization. Atmospheric water harvesting (AWH) is a promising solution where clean water is collected from the air through various approaches, including dropwise condensation. However, designing surfaces that balance rapid condensation with efficient water removal is challenging. To address this issue, inspired by the efficient water collection mechanisms in the skin of cold-blooded tree frogs, we propose an eco-friendly approach to collect fresh water from cooled window glass. We fabricated various planar and TiO2 nanostructured surfaces including surfaces mimicking a lotus leaf and a hybrid surface mimicking a desert beetle and a cactus, with different wettability levels such as superhydrophilic, hydrophilic, hydrophobic, superhydrophobic, and biphilic. Sub-cooling of glass substrates between 5 and 15 °C using a Peltier device significantly enhanced the condensation process for all surfaces, with modest dependency on surface properties. This cooling temperature regime could be achieved by geothermal cooling methods that consume little energy. To improve visibility for window applications, we developed hydrophobic polymer nanofilm-modified glass substrates using a simple spin-coating technique, and achieved comparable water harvesting efficiency to that of nanostructured substrates. Our study provides insight into the optimal surface structures and cooling temperature for window glass AWH systems that could be used with an underground cooling system.
| S-EPMC10366654 | biostudies-literature
Project description:Triboelectric nanogenerators (TENG) have shown great potential in harvesting energy from water. For the TENG that harvests water energy, surface hydrophobicity is crucial for its performance. In this paper, we prepare a hydrophobic composite film of Polyvinylidene Fluoride/Polydimethylsiloxane/Polytetrafluoroethylene (PVDF/PDMS/PTFE) and an electrode of Polyaniline/Carbon nanotubes/Silver nanowires (PANI/CNTs/AgNWs) by electrospinning technology and a doping method, respectively, which are served as the friction layer and top electrode of TENG. The contact angle of the hydrophobic film and electrode both reach over 120°, which makes the separation process between water and the interface complete and promotes the output of TENG. The open-circuit voltage (Voc) and short-circuit current (Isc) can reach 150 V and 60 μA approximately. In addition, the composite electrode can be applied in the preparation of complex electrode shapes. Furthermore, the different reactions of TENG to different liquids indicate that it may contribute to liquid-type sensing systems. This work presents an efficient approach to fabricating hydrophobic films and electrodes, laying a foundation for the development of TENG for harvesting water energy.
| S-EPMC10419362 | biostudies-literature
Project description:The need for sustainable technologies to address environmental pollution and energy crisis is paramount. Here we present a novel multifunctional nanocomposite, free standing film by combining piezoelectric molybdenum sulphide (MoS2) nanoflower with poly vinylidene fluoride (PVDF) polymer, which can harness otherwise wasted mechanical energy for useful energy generation and/or water purification. The unique MoS2 nanoflower morphology is exploited to render the whole nanocomposite piezo active. A number of features are demonstrated to establish potential practical usage. Firstly, the nanocomposite is piezoelectric and piezocatalytic simultaneously without requiring any poling step (i.e. self-poled). Secondly, the self-poled piezoelectricity is exploited to make a nanogenerator. The nanogenerator produced >80 V under human finger tapping with a remarkable power density, reaching 47.14 mW cm-3. The nanocomposite film is made by simple solution casting, and the corresponding nanogenerator powers up 25 commercial LEDs by finger tapping. Last but not the least, the developed films show efficient, fast and stable piezocatalytic dye degradation efficiency (>90% within 20 min) against four different toxic and carcinogenic dyes under dark condition. Reusability of at least 10 times is also demonstrated without any loss of catalytic activity. Overall, our nanocomposite has clear potential for use as self-powered sensor and energy harvester, and in water remediation systems. It should potentially also be deployable as a surface mounted film/coating in process engineering, industrial effluent management and healthcare devices systems.
| S-EPMC8417815 | biostudies-literature
Project description:Access to clean water is a global challenge, and fog collectors are a promising solution. Polycarbonate (PC) fibers have been used in fog collectors but with limited efficiency. In this study, we show that controlling voltage polarity and humidity during the electrospinning of PC fibers improves their surface properties for water collection capability. We experimentally measured the effect of both the surface morphology and the chemistry of PC fiber on their surface potential and mechanical properties in relation to the water collection efficiency from fog. PC fibers produced at high humidity and with negative voltage polarity show a superior water collection rate combined with the highest tensile strength. We proved that electric potential on surface and morphology are crucial, as often designed by nature, for enhancing the water collection capabilities via the single-step production of fibers without any postprocessing needs.
| S-EPMC8158858 | biostudies-literature
Project description:We present the first data on the metabolic costs of horizontal jumping in humans, using this tractable model to explore variations in energy expenditure with substrate properties, and consider these findings in light of kinematic data. Twenty-four participants jumped consistently at the rate of 1 jump per 5?s between opposing springboards separated by either a short (1.2?m) or long (1.8?m) gap. Springboards were either 'firm' or 'compliant'. Respiratory gas exchange was measured using a back-mounted portable respiratory gas analyser to represent rate of energy expenditure, which was converted to energy expenditure per metre jumped. Video data were recorded to interpret kinematic information. Horizontal jumping was found to be between around 10 and 20 times the energy cost of cursorial locomotion per unit distance moved. There is considerable evidence from the data that jumping 1.8?m from a compliant springboard (134.9?mL O2?m(-1)) is less costly energetically than jumping that distance from a firm springboard (141.6?mL O2 m(-1)), albeit the effect size is quite small within the range of compliances tested in this study. However, there was no evidence of an effect of springboard type for jumps of 1.2 m. The kinematic analyses indicate possible explanations for these findings. Firstly, the calf muscle is likely used more, and the thigh muscles less, to take-off from a firm springboard during 1.8 m jumps, which may result in the power required to take-off being produced less efficiently. Secondly, the angle of take-off from the compliant surface during 1.8 m jumps is closer to the optimal for energetic efficiency (45°), possible due to the impulse provided by the surface as it returns stored energy during the final stages of the take-off. The theoretical effect on energy costs due to a different take-off angle for jumps of only 1.2 m is close to negligible.
| S-EPMC4163658 | biostudies-literature
Project description:A variety of autonomous oscillations in nature such as heartbeats and some biochemical reactions have been widely studied and utilized for applications in the fields of bioscience and engineering. Here, we report a unique phenomenon of moisture-induced electrical potential oscillations on polymers, poly([2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide-co-acrylic acid), during the diffusion of water molecules. Chemical reactions are modeled by kinetic simulations while system dynamic equations and the stability matrix are analyzed to show the chaotic nature of the system which oscillates with hidden attractors to induce the autonomous surface potential oscillation. Using moisture in the ambient environment as the activation source, this self-excited chemoelectrical reaction could have broad influences and usages in surface-reaction based devices and systems. As a proof-of-concept demonstration, an energy harvester is constructed and achieved the continuous energy production for more than 15,000 seconds with an energy density of 16.8 mJ/cm2. A 2-Volts output voltage has been produced to power a liquid crystal display toward practical applications with five energy harvesters connected in series.
| S-EPMC8421362 | biostudies-literature
Project description:Reversed-electrowetting based droplet electricity generator (REWOD-DEG) shows merits in high power densities, tunable output formats, and wide adaptability to diverse mechanical energies. However, the surface charge trapping and dielectric failure, which are also common challenges for electrowetting system, hinders the development of reliable REWOD-DEGs for long-term running. We innovatively introduce a slippery lubricant-infused porous surface (SLIPS) into REWOD-DEG. Benefits from the significant inhibitory effect for surface charge trapping and ambient contamination, self-healing characteristic given by SLIPS, and robust reversed-electrowetting based energy harvesting were achieved. The SLIPS enhanced REWOD-DEG experienced 100 days of intermittent energy harvesting without deterioration. In addition, the device shows robust performances when exposed to a variety of extreme working conditions, like low temperature, pH, humidity, fouling, and even scratching. This work may address the core application challenges of REWOD based devices, and inspire the development of other robust droplet-based electricity generators.
| S-EPMC10613949 | biostudies-literature
Project description:Previous studies have shown that copolymer compositions can significantly impact self-healing properties. This was accomplished by enhancement of van der Waals (vdW) forces which facilitate self-healing in relatively narrow copolymer compositional range. In this work we report the acceleration of self-healing in alternating/random hydrophobic acrylic-based copolymers in the presence of confined water molecules. Under these conditions competing vdW interactions do not allow H2O-diester H-bonding, thus forcing nBA side groups to adapt L-shape conformations, generating stronger dipole-dipole interactions resulting in shorter inter-chain distances compared to 'key-and-lock' associations without water. The perturbation of vdW forces upon mechanical damage in the presence of controllable amount of confined water is energetically unfavorable leading the enhancement of self-healing efficiency of hydrophobic copolymers by a factor of three. The concept may be applicable to other self-healing mechanisms involving reversible covalent bonding, supramolecular chemistry, or polymers with phase-separated morphologies.
| S-EPMC7665198 | biostudies-literature
Project description:The dynamic motion of a water droplet on an inclined hydrophobic surface is analyzed with and without environmental dust particles on the surface. Solution crystallization of a polycarbonate surface is carried out to generate a hydrophobic surface with hierarchical texture composed of micro/nanosize spheroids and fibrils. Functionalized nanosize silica particles are deposited on the textured surface to reduce contact angle hysteresis. Environmental dust particles are collected and characterized using analytical tools prior to the experiments. The droplet motion on the hydrophobic surface is assessed using high-speed camera data, and then, the motion characteristics are compared with the corresponding analytical results. The influence of dust particles on the water droplet motion and the amount of dust particles picked up from the hydrophobic surface by the moving droplet is evaluated experimentally. A 40 ?L droplet was observed to roll on the hydrophobic surface with and without dust particles, and the droplet slip velocity was lower than the rotational velocity. The rolling droplet removes almost all dust particles from the surface, and the mechanism for the removal of dust particles from the surface was determined to be water cloaking of the dust particles.
| S-EPMC5813023 | biostudies-literature
Project description:We report the experimental observation of energetically confined self-accelerating optical beams propagating along various convex trajectories. We show that, under an appropriate transverse compression of their spatial spectra, these self-accelerating beams can exhibit a dramatic enhancement of their peak intensity and a significant decrease of their transverse expansion, yet retaining both the expected acceleration profile and the intrinsic self-healing properties. We found our experimental results to be in excellent agreement with the numerical simulations. We expect further applications in such contexts where power budget and optimal spatial confinement can be important limiting factors.
| S-EPMC4547394 | biostudies-other