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Hiroyuki Ohshima - One of the best experts on this subject based on the ideXlab platform.
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approximate expressions for the Surface Charge Density Surface potential relationship and double layer potential distribution for a spherical or cylindrical colloidal particle based on the modified poisson boltzmann equation
Colloid and Polymer Science, 2018Co-Authors: Hiroyuki OhshimaAbstract:Approximate expressions for the Surface Charge Density/Surface potential relationship and double-layer potential distribution are derived for a spherical or cylindrical colloidal particle in an electrolyte solution. The obtained expressions are based on an approximate form of the modified Poisson-Boltzmann equation taking into account the ion size effects through the Carnahan-Starling activity coefficients of electrolyte ions. We further derive approximate expression for the effective Surface potentials of a spherical or cylindrical particle and for the electrostatic interaction energy between two spherical or cylindrical particles on the basis of the linear superposition approximation.
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Electrophoretic mobility of a colloidal particle with constant Surface Charge Density.
Langmuir, 2010Co-Authors: Kimiko Makino, Hiroyuki OhshimaAbstract:When the electrophoretic mobility of a particle in an electrolyte solution is measured, the obtained electrophoretic mobility values are usually converted to the particle zeta potential with the help of a proper relationship between the electrophoretic mobility and the zeta potential. For a particle with constant Surface Charge Density, however, the Surface Charge Density should be a more characteristic quantity than the zeta potential because for such particles the zeta potential is not a constant quantity but depends on the electrolyte concentration. In this article, a systematic method that does not require numerical computer calculation is proposed to determine the Surface Charge Density of a spherical colloidal particle on the basis of the particle electrophoretic mobility data. This method is based on two analytical equations, that is, the relationship between the electrophoretic mobility and zeta potential of the particle and the relationship between the zeta potential and Surface Charge Density of the particle. The measured mobility values are analyzed with these two equations. As an example, the present method is applied to electrophoretic mobility data on gold nanoparticles (Agnihotri, S. M.; Ohshima, H.; Terada, H.; Tomoda, K.; Makino, K. Langmuir 2009, 25, 4804).
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Surface Charge Density Surface potential relationship for a spherical colloidal particle in a salt free medium
Joint International Conference on Information Sciences, 2002Co-Authors: Hiroyuki OhshimaAbstract:On the basis of a theory of Imai and Oosawa (Busseiron Kenkyu52, 42 (1952); 59, 99 (1953)), approximate analytic expressions for the Surface Charge Density/Surface potential relationship for a spherical colloidal particle in a salt-free (aqueous or nonaqueous) medium containing only counterions are derived. There is a certain critical value of the Surface Charge Density (or the total Surface Charge) separating two distinct cases: low Surface Charge Density case and high Surface Charge Density case. In the latter case counterion condensation occurs in the vicinity of the particle Surface. The results are in excellent agreement with numerical calculations for the case of dilute suspensions.
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double layer potential distribution and Surface Charge Density Surface potential relationship for a nearly spherical spheroid in an electrolyte solution
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2000Co-Authors: Hiroyuki OhshimaAbstract:Abstract A simple approximation method is presented to derive the double layer potential distribution and the Surface Charge Density/Surface potential relationship for a nearly spherical spheroidal colloidal particle immersed in an electrolyte solution on the basis of the linearized Poisson–Boltzmann equation.
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approximate expression for the double layer interaction energy between two parallel plates with constant Surface Charge Density
Joint International Conference on Information Sciences, 1999Co-Authors: Hiroyuki OhshimaAbstract:Abstract An approximate expression for the potential energy of the double-layer interaction between two parallel similar plates with constant Surface Charge Density is derived via a novel linearization method, in which the Poisson–Boltzmann is linearized with respect to the deviation of the electric potential from the Surface potential (which is a function of the interplate separation h ). This approximation works quite well for small plate separations h for all values of the Surface Charge Density (or the unperturbed Surface potential) and gives a correct limiting form of the interaction energy (or the interaction force) as h → 0.
Zhong Lin Wang - One of the best experts on this subject based on the ideXlab platform.
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scanning triboelectric nanogenerator as a nanoscale probe for measuring local Surface Charge Density on a dielectric film
Applied Physics Letters, 2021Co-Authors: Shiquan Lin, Zhong Lin WangAbstract:Inspired by the contact-separation mode triboelectric nanogenerator (TENG), we propose a technique for local Surface Charge Density measurement based on atomic force microscopy. It is named as scanning TENG, in which a conductive tip tapping above a Charged dielectric Surface produces an AC between the tip and the dielectric bottom electrode due to electrostatic induction. The Fourier analysis shows that the amplitude of the first harmonic of the AC is linearly related to Surface Charge Density. The results demonstrate that the scanning TENG is a powerful tool for probing nanoscale Charge transfer in contact-electrification.
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rationally patterned electrode of direct current triboelectric nanogenerators for ultrahigh effective Surface Charge Density
Nature Communications, 2020Co-Authors: Zhong Lin Wang, Zhihao Zhao, Yejing Dai, Di Liu, Linglin Zhou, Jie WangAbstract:As a new-era of energy harvesting technology, the enhancement of triboelectric Charge Density of triboelectric nanogenerator (TENG) is always crucial for its large-scale application on Internet of Things (IoTs) and artificial intelligence (AI). Here, a microstructure-designed direct-current TENG (MDC-TENG) with rationally patterned electrode structure is presented to enhance its effective Surface Charge Density by increasing the efficiency of contact electrification. Thus, the MDC-TENG achieves a record high Charge Density of ~5.4 mC m−2, which is over 2-fold the state-of-art of AC-TENGs and over 10-fold compared to previous DC-TENGs. The MDC-TENG realizes both the miniaturized device and high output performance. Meanwhile, its effective Charge Density can be further improved as the device size increases. Our work not only provides a miniaturization strategy of TENG for the application in IoTs and AI as energy supply or self-powered sensor, but also presents a paradigm shift for large-scale energy harvesting by TENGs. Low Charge Density is the bottleneck for the applications of triboelectric nanogenerator (TENG). Here, the authors demonstrate a microstructure-designed direct-current TENG with rationally patterned electrode structure to enhance its effective Charge Density to a new milestone.
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rationally patterned electrode of direct current triboelectric nanogenerators for ultrahigh effective Surface Charge Density
Nature Communications, 2020Co-Authors: Zhihao Zhao, Zhong Lin Wang, Yejing Dai, Di Liu, Linglin Zhou, Jie WangAbstract:As a new-era of energy harvesting technology, the enhancement of triboelectric Charge Density of triboelectric nanogenerator (TENG) is always crucial for its large-scale application on Internet of Things (IoTs) and artificial intelligence (AI). Here, a microstructure-designed direct-current TENG (MDC-TENG) with rationally patterned electrode structure is presented to enhance its effective Surface Charge Density by increasing the efficiency of contact electrification. Thus, the MDC-TENG achieves a record high Charge Density of ~5.4 mC m-2, which is over 2-fold the state-of-art of AC-TENGs and over 10-fold compared to previous DC-TENGs. The MDC-TENG realizes both the miniaturized device and high output performance. Meanwhile, its effective Charge Density can be further improved as the device size increases. Our work not only provides a miniaturization strategy of TENG for the application in IoTs and AI as energy supply or self-powered sensor, but also presents a paradigm shift for large-scale energy harvesting by TENGs.
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manipulating the triboelectric Surface Charge Density of polymers by low energy helium ion irradiation implantation
Energy and Environmental Science, 2020Co-Authors: Yong Fan, H. Chen, Jinhui Nie, Yanxia Liang, Xinglin Tao, Jian Zhang, Xiangyu Chen, Zhong Lin WangAbstract:Triboelectric materials and their modification methods are the cornerstones for fabricating triboelectric nanogenerators (TENGs). Numerous modification methods have been proposed for TENGs, while a highly effective and long-term stable method is still under exploration. Here, a Surface modification method using low-energy ion irradiation has been proposed for tuning the chemical structures and functional groups of triboelectric polymers at the molecular level. The low-energy ion irradiation brings negligible change to the Surface roughness at the micro-scale and mechanical flexibility of the target polymer, while it can provide a stable modification of the electrification performance. Systematic studies about the chemical structure changes in four different polymers induced by ion irradiation can bring insight into the interaction between different chemical groups and electrification performance. A Kapton film modified by ion irradiation shows several unprecedented characteristics, such as high Surface Charge Density, excellent stability and ultrahigh electron-donating capability, and not only creates a new record in the tribo series, but also provides a good demonstration for regulating electrification behavior based on controllable chemical structure change. This study can open up a series of possible breakthroughs in the production of triboelectric materials with diversified properties, which can promote the study of TENGs from a very fundamental level.
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Surface Charge Density of triboelectric nanogenerators theoretical boundary and optimization methodology
Applied Materials Today, 2020Co-Authors: Chunlei Zhang, Zhong Lin Wang, Di Liu, Linglin Zhou, Ping Cheng, Xing Yin, Hengyu Guo, Jie WangAbstract:Abstract Although high Charge densities of triboelectric nanogenerators (TENG) were achieved by working in high vacuum or Charge pumping techniques in atmosphere, owing to their complex structure and/or stability issues, it still remains a great challenge and necessity to directly obtain the high Charge Density directly through triboelectrification effect in atmosphere. Here, a basic theory about the limitation factors of Surface Charge Density is comprehensively rebuilt through analytical mathematical derivation of the limitation equation. As a result, high Surface Charge Density can be obtained directly by a new optimization methodology, i.e. using thin dielectric layer, which is demonstrated by the designed contact-separation model TENG and sliding model TENG. In addition, the theoretical models of Charge decay and Charge accumulation during triboelectrification process were built. This work provides not only a new facile and universal optimization methodology for TENG, but also a new insight in the triboelectrification process, both of which will prompt the applications of TENG ranging from powering electronic devices to harvesting large-scale blue energy.
Jyhping Hsu - One of the best experts on this subject based on the ideXlab platform.
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ultrashort nanopores of large radius can generate anomalously high salinity gradient power
Electrochimica Acta, 2020Co-Authors: Weicheng Huang, Jyhping HsuAbstract:Abstract Using ultrashort nanopores in salinity gradient power seems promising, however, their poor ion selectivity is disadvantageous. We show that this difficulty can be circumvented by adopting a two-dimensional material having a high Surface Charge Density. Through raising the Surface Charge Density, both the electric power and the transference number can both be enhanced effectively. For example, for a cylindrical nanopore having length 2 nm, radius 2 nm and Surface Charge Density -1000 mC/m2, the transference number can approach ca. 0.97 and the electric power ca. 200 pW if the salt concentration ratio across the nanopore is (1000/1), much higher than previous reported values of 3.13 pW in similar systems having longer pores (∼1000 nm) and lower Surface Charge Density (∼-60 mC/m2). The underlying mechanisms of the present novel salinity gradient power system are investigated in detail for the first time. In particular, the profiles for the concentration of ions and its flux inside the nanopore are examined to explain the ion transport phenomena observed. Anomalously, if the Surface Charge Density is sufficiently high (e.g., -1000 mC/m2), a nanopore of radius as large as 50 nm can still generate appreciable electric power (ca. 45 pW).
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approximate analytical expression for Surface potential as a function of Surface Charge Density
Journal of Colloid and Interface Science, 1995Co-Authors: Jyhping Hsu, Yungchih KuoAbstract:Abstract The Surface potential is derived as a function of Surface Charge Density for a nonplanar solid Surface immersed in an arbitrary a:b electrolyte solution. This relation is essential to the evaluation of the basic thermodynamic properties of an electrical double layer. The approximate analytical expression is based on a perturbation method characterized by the following ratio: radius of a Surface/thickness of a double layer. An attempt is also made to take the inverse of the Surface-Charge Density-Surface potential relation for a spherical Surface immersed in both 1:1 and 1:2 electrolyte solutions as reported by H. Ohshima, T. W. Healy, and L. R. White (J. Colloid Interface Sci.90, 17, 1982). For a 1:1 electrolyte solution, the maximum deviation from the exact value is on the order of 3% for a double layer of thickness smaller than one half the radius of a Surface, and this is almost independent of the magnitude of Surface Charge Density. For a 1:2 electrolyte solution, the maximal deviation appears to increase slightly with Surface Charge Density. At a relatively low Surface Charge Density, the deviation is on the order of 3% for a double layer having thickness less than one-half the radius of a sphere, and it is on the order of 5% at a relatively high Surface Charge Density.
Zhengfei Kuang - One of the best experts on this subject based on the ideXlab platform.
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reverse electrodialysis in bilayer nanochannels salinity gradient driven power generation
Physical Chemistry Chemical Physics, 2018Co-Authors: Rui Long, Zhengfei KuangAbstract:To evaluate the possibility of nano-fluidic reverse electrodialysis (RED) for salinity gradient energy harvesting, we consider the behavior of ion transportation in a bilayer cylindrical nanochannel consisting of different sized nanopores connecting two large reservoirs at different NaCl concentrations. Numerical simulations to illustrate the electrokinetic behavior at asymmetric sub-pore length and Surface Charge Density are conducted, the impacts of which on transference number, osmotic current, diffusive voltage, maximum power and maximum power efficiency are systematically investigated. The results reveal that the transference number in Config. I (where high NaCl concentration is applied at the larger nanopore) is always larger than that in the opposite configuration (Config. II). At low concentration ratios, the osmotic current and maximum power have maximum values, while the maximum power efficiency decreases consistently. For Config. II, the ion transportation is impacted by the Surface Charge Density at both sub-nanopores, while for Config. I, it is determined by the Surface Charge Density at the downstream small nanopore. When large Surface Charge Density is applied at the downstream small nanopore in contact with a very low concentration reservoir, there exists an interesting phenomenon: the larger Surface Charge Density at the large nanopore induces a slight performance drop due to the impact of upstream EDL overlap.
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reverse electrodialysis in bilayer nanochannels salinity gradient driven power generation
Physical Chemistry Chemical Physics, 2018Co-Authors: Rui Long, Zhengfei Kuang, Zhichun Liu, Wei LiuAbstract:To evaluate the possibility of nano-fluidic reverse electrodialysis (RED) for salinity gradient energy harvesting, we consider the behavior of ion transportation in a bilayer cylindrical nanochannel consisting of different sized nanopores connecting two large reservoirs at different NaCl concentrations. Numerical simulations to illustrate the electrokinetic behavior at asymmetric sub-pore length and Surface Charge Density are conducted, the impacts of which on transference number, osmotic current, diffusive voltage, maximum power and maximum power efficiency are systematically investigated. The results reveal that the transference number in Config. I (where high NaCl concentration is applied at the larger nanopore) is always larger than that in the opposite configuration (Config. II). At low concentration ratios, the osmotic current and maximum power have maximum values, while the maximum power efficiency decreases consistently. For Config. II, the ion transportation is impacted by the Surface Charge Density at both sub-nanopores, while for Config. I, it is determined by the Surface Charge Density at the downstream small nanopore. When large Surface Charge Density is applied at the downstream small nanopore in contact with a very low concentration reservoir, there exists an interesting phenomenon: the larger Surface Charge Density at the large nanopore induces a slight performance drop due to the impact of upstream EDL overlap.
Jie Wang - One of the best experts on this subject based on the ideXlab platform.
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rationally patterned electrode of direct current triboelectric nanogenerators for ultrahigh effective Surface Charge Density
Nature Communications, 2020Co-Authors: Zhong Lin Wang, Zhihao Zhao, Yejing Dai, Di Liu, Linglin Zhou, Jie WangAbstract:As a new-era of energy harvesting technology, the enhancement of triboelectric Charge Density of triboelectric nanogenerator (TENG) is always crucial for its large-scale application on Internet of Things (IoTs) and artificial intelligence (AI). Here, a microstructure-designed direct-current TENG (MDC-TENG) with rationally patterned electrode structure is presented to enhance its effective Surface Charge Density by increasing the efficiency of contact electrification. Thus, the MDC-TENG achieves a record high Charge Density of ~5.4 mC m−2, which is over 2-fold the state-of-art of AC-TENGs and over 10-fold compared to previous DC-TENGs. The MDC-TENG realizes both the miniaturized device and high output performance. Meanwhile, its effective Charge Density can be further improved as the device size increases. Our work not only provides a miniaturization strategy of TENG for the application in IoTs and AI as energy supply or self-powered sensor, but also presents a paradigm shift for large-scale energy harvesting by TENGs. Low Charge Density is the bottleneck for the applications of triboelectric nanogenerator (TENG). Here, the authors demonstrate a microstructure-designed direct-current TENG with rationally patterned electrode structure to enhance its effective Charge Density to a new milestone.
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rationally patterned electrode of direct current triboelectric nanogenerators for ultrahigh effective Surface Charge Density
Nature Communications, 2020Co-Authors: Zhihao Zhao, Zhong Lin Wang, Yejing Dai, Di Liu, Linglin Zhou, Jie WangAbstract:As a new-era of energy harvesting technology, the enhancement of triboelectric Charge Density of triboelectric nanogenerator (TENG) is always crucial for its large-scale application on Internet of Things (IoTs) and artificial intelligence (AI). Here, a microstructure-designed direct-current TENG (MDC-TENG) with rationally patterned electrode structure is presented to enhance its effective Surface Charge Density by increasing the efficiency of contact electrification. Thus, the MDC-TENG achieves a record high Charge Density of ~5.4 mC m-2, which is over 2-fold the state-of-art of AC-TENGs and over 10-fold compared to previous DC-TENGs. The MDC-TENG realizes both the miniaturized device and high output performance. Meanwhile, its effective Charge Density can be further improved as the device size increases. Our work not only provides a miniaturization strategy of TENG for the application in IoTs and AI as energy supply or self-powered sensor, but also presents a paradigm shift for large-scale energy harvesting by TENGs.
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Surface Charge Density of triboelectric nanogenerators theoretical boundary and optimization methodology
Applied Materials Today, 2020Co-Authors: Chunlei Zhang, Zhong Lin Wang, Di Liu, Linglin Zhou, Ping Cheng, Xing Yin, Hengyu Guo, Jie WangAbstract:Abstract Although high Charge densities of triboelectric nanogenerators (TENG) were achieved by working in high vacuum or Charge pumping techniques in atmosphere, owing to their complex structure and/or stability issues, it still remains a great challenge and necessity to directly obtain the high Charge Density directly through triboelectrification effect in atmosphere. Here, a basic theory about the limitation factors of Surface Charge Density is comprehensively rebuilt through analytical mathematical derivation of the limitation equation. As a result, high Surface Charge Density can be obtained directly by a new optimization methodology, i.e. using thin dielectric layer, which is demonstrated by the designed contact-separation model TENG and sliding model TENG. In addition, the theoretical models of Charge decay and Charge accumulation during triboelectrification process were built. This work provides not only a new facile and universal optimization methodology for TENG, but also a new insight in the triboelectrification process, both of which will prompt the applications of TENG ranging from powering electronic devices to harvesting large-scale blue energy.
