Pub Date : 2021-07-03DOI: 10.1080/19475411.2021.1973143
Xuyao An, Chunnan Wang, Ruomei Shao, Shuqing Sun
ABSTRACT Self-powered technology is a novel power supply technology. In recent years, self-powered intelligent products have attracted much interests. Triboelectric nanogenerators (TENGs) can convert mechanical energy into electrical energy by contact and relative motion, thus providing the possibility of self-powering for electronic equipments. However, TENG-based self-powered technologies are limited by low power output and poor conversion efficiency. In this review, we present the development of TENG-based self-powered systems, with the emphasis on the output power of TENG and how to improve it. Based on the above applications, we propose the idea of TENG-driven self-powered remote robots, providing promising scenarios of small remote robots for land rescue or underwater detection. Due to the limited power output of the current TENGs, there are still some difficulties in driving the robot. Aiming at the problems of low power supply and poor conversion efficiency, we introduce the current attempts to improve the power generation efficiency from the perspectives of mechanical structure, electrode materials and auxiliary tools. We also outline the applications of TENGs as power supply systems in various fields such as sensing, wearable devices, and collecting Marine energy. Finally, we forecast the development prospect of TENG. Graphical abstract
{"title":"Advances and prospects of triboelectric nanogenerator for self-powered system","authors":"Xuyao An, Chunnan Wang, Ruomei Shao, Shuqing Sun","doi":"10.1080/19475411.2021.1973143","DOIUrl":"https://doi.org/10.1080/19475411.2021.1973143","url":null,"abstract":"ABSTRACT Self-powered technology is a novel power supply technology. In recent years, self-powered intelligent products have attracted much interests. Triboelectric nanogenerators (TENGs) can convert mechanical energy into electrical energy by contact and relative motion, thus providing the possibility of self-powering for electronic equipments. However, TENG-based self-powered technologies are limited by low power output and poor conversion efficiency. In this review, we present the development of TENG-based self-powered systems, with the emphasis on the output power of TENG and how to improve it. Based on the above applications, we propose the idea of TENG-driven self-powered remote robots, providing promising scenarios of small remote robots for land rescue or underwater detection. Due to the limited power output of the current TENGs, there are still some difficulties in driving the robot. Aiming at the problems of low power supply and poor conversion efficiency, we introduce the current attempts to improve the power generation efficiency from the perspectives of mechanical structure, electrode materials and auxiliary tools. We also outline the applications of TENGs as power supply systems in various fields such as sensing, wearable devices, and collecting Marine energy. Finally, we forecast the development prospect of TENG. Graphical abstract","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"233 - 255"},"PeriodicalIF":3.9,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43143004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-03DOI: 10.1080/19475411.2021.1901792
Junya Wu, Sha Yi, Yixuan Wang, Jun Yao, Wei Gao
ABSTRACT Titanium dioxide (TiO2) nanoparticles are efficient photocatalysis for treating organic pollutants in water. Immobilizing TiO2 nanoparticles not only enables the reuse of nanoparticles but also prevents the harmful impact of releasing nanoparticles into the aquatic environment. In this study, a porous composite microfiber membrane based on polyacrylonitrile (PAN) with TiO2 nanoparticles has been synthesized by electrospinning technique. The new membrane system has exhibited excellent adsorptive-photocatalytic property to degrade Methylene blue (MB). Using the nonlinear form of the pseudo-first-order, pseudo-second-order, Elovich, and Intra-particle diffusion models, the adsorption mechanism was analyzed. Coupling with adsorption and photocatalysis, the efficiency of this membrane system was illustrated via the multistage linear form of the pseudo-first-order kinetic; and the electrical energy per order (EEO) confirmed the lowest energy requirements to transfer selected pollutants. Combining the results of SEM, BET, FTIR, XRD and TGA, it revealed the relationship of microstructure, composition, and MB decomposition performance. The finding presents new knowledge for material design and evaluation of polymers/oxides membrane systems for remediating organic pollutants in water. Graphical abstract
{"title":"Polymer-based TiO2 nanocomposite membrane: synthesis and organic pollutant removal","authors":"Junya Wu, Sha Yi, Yixuan Wang, Jun Yao, Wei Gao","doi":"10.1080/19475411.2021.1901792","DOIUrl":"https://doi.org/10.1080/19475411.2021.1901792","url":null,"abstract":"ABSTRACT Titanium dioxide (TiO2) nanoparticles are efficient photocatalysis for treating organic pollutants in water. Immobilizing TiO2 nanoparticles not only enables the reuse of nanoparticles but also prevents the harmful impact of releasing nanoparticles into the aquatic environment. In this study, a porous composite microfiber membrane based on polyacrylonitrile (PAN) with TiO2 nanoparticles has been synthesized by electrospinning technique. The new membrane system has exhibited excellent adsorptive-photocatalytic property to degrade Methylene blue (MB). Using the nonlinear form of the pseudo-first-order, pseudo-second-order, Elovich, and Intra-particle diffusion models, the adsorption mechanism was analyzed. Coupling with adsorption and photocatalysis, the efficiency of this membrane system was illustrated via the multistage linear form of the pseudo-first-order kinetic; and the electrical energy per order (EEO) confirmed the lowest energy requirements to transfer selected pollutants. Combining the results of SEM, BET, FTIR, XRD and TGA, it revealed the relationship of microstructure, composition, and MB decomposition performance. The finding presents new knowledge for material design and evaluation of polymers/oxides membrane systems for remediating organic pollutants in water. Graphical abstract","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"129 - 145"},"PeriodicalIF":3.9,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1901792","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44423918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT We report the synthesis of cellulose membranes from balsa wood with an exceptionally high responsivity to humidity change by chemical processing and mechanical compression. By varying the ambient humidity, the produced cellulose membranes can provide a variety of predetermined deformations, such as curve, s-like deformation and curl. The high humidity responsivity is originated from a self-maintained moisture gradient induced by an asymmetrical design of membrane surfaces, aided by the hygroscopic swelling of the cellulose. The moisture-driven actuators are then demonstrated as a three-finger gripper that can grab, hold and release objects 40 times the weight of its own. The combination of natural wood and stimuli-responsive behavior open a way to designing smart structures, actuators and soft robots with environmentally friendly, recyclable and biocompatible materials. Graphical abstract
{"title":"Cellulose membranes as moisture-driven actuators with predetermined deformations and high load uptake","authors":"X. Jiang, Bingkun Tian, Xiaoyu Xuan, Wanqi Zhou, Jianxin Zhou, Yaqing Chen, Yang Lu, Zhuhua Zhang","doi":"10.1080/19475411.2021.1906780","DOIUrl":"https://doi.org/10.1080/19475411.2021.1906780","url":null,"abstract":"ABSTRACT We report the synthesis of cellulose membranes from balsa wood with an exceptionally high responsivity to humidity change by chemical processing and mechanical compression. By varying the ambient humidity, the produced cellulose membranes can provide a variety of predetermined deformations, such as curve, s-like deformation and curl. The high humidity responsivity is originated from a self-maintained moisture gradient induced by an asymmetrical design of membrane surfaces, aided by the hygroscopic swelling of the cellulose. The moisture-driven actuators are then demonstrated as a three-finger gripper that can grab, hold and release objects 40 times the weight of its own. The combination of natural wood and stimuli-responsive behavior open a way to designing smart structures, actuators and soft robots with environmentally friendly, recyclable and biocompatible materials. Graphical abstract","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"146 - 156"},"PeriodicalIF":3.9,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1906780","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47751682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT In this work, we printed a Nafion precursor membrane by fused deposition modeling (FDM) rapid prototyping technology and further fabricated IPMCs by electroless plating. The ion-exchange capacity of the Nafion membrane was tested, and the morphology of IPMCs was observed. The electro-mechanical properties of IPMCs under AC voltage inputs were studied, and grasping experiments were performed. The results show that the Nafion membrane after hydrolysis has a good ion-exchange ability and water-holding capacity. SEM observed that the thickness of the IPMC’s electrode layer was about 400 nm, and the platinum layer was tightly combined with the substrate membrane. When using a square wave input of 3.5 V and 0.1 Hz, the maximum current of IPMCs reached 0.30 A, and the displacement and blocking force were 7.57 mm and 10.5 mN, respectively. The new fabrication process ensures the good driving performance of the printed IPMC. And two pieces of IPMCs can capture the irregular objects successfully, indicating the feasibility of printing IPMCs by FDM technology. This paper provides a new and simple method for the fabrication of three-dimensional IPMCs, which can be further applied in flexible grippers and soft robotics. GRAPHICAL ABSTRACT
{"title":"Printing ionic polymer metal composite actuators by fused deposition modeling technology","authors":"Guoxiao Yin, Qing-song He, Xiangman Zhou, Yu-Wang Wu, Hongkai Li, Min Yu","doi":"10.1080/19475411.2021.1914766","DOIUrl":"https://doi.org/10.1080/19475411.2021.1914766","url":null,"abstract":"ABSTRACT In this work, we printed a Nafion precursor membrane by fused deposition modeling (FDM) rapid prototyping technology and further fabricated IPMCs by electroless plating. The ion-exchange capacity of the Nafion membrane was tested, and the morphology of IPMCs was observed. The electro-mechanical properties of IPMCs under AC voltage inputs were studied, and grasping experiments were performed. The results show that the Nafion membrane after hydrolysis has a good ion-exchange ability and water-holding capacity. SEM observed that the thickness of the IPMC’s electrode layer was about 400 nm, and the platinum layer was tightly combined with the substrate membrane. When using a square wave input of 3.5 V and 0.1 Hz, the maximum current of IPMCs reached 0.30 A, and the displacement and blocking force were 7.57 mm and 10.5 mN, respectively. The new fabrication process ensures the good driving performance of the printed IPMC. And two pieces of IPMCs can capture the irregular objects successfully, indicating the feasibility of printing IPMCs by FDM technology. This paper provides a new and simple method for the fabrication of three-dimensional IPMCs, which can be further applied in flexible grippers and soft robotics. GRAPHICAL ABSTRACT","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"218 - 231"},"PeriodicalIF":3.9,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1914766","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45250527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs, thereby greatly improving the photocatalytic hydrogen production performance of the photocatalyst. In this paper, Bi6O6(OH)3(NO3)3 · 1.5H2O (BBN) and ZnO are used to construct and synthesize Bi6O6(OH)3(NO3)3 · 1.5H2O/ZnO (BBN/ZnO) heterojunction photocatalyst. Under UV-vis light irradiation, the BBN/ZnO composite could generate H2 with a rate of 28.66 μmol·g−1·h−1, which is higher than pure BBN (0.92 μmol·g−1·h−1) and ZnO (6.54 μmol·h−1·g−1) at around 31.1 and 4.4 times, respectively. Moreover, the experimental results found that the composite still exhibits excellent photocatalytic activity and maintains a high and stable activity in the 12-hour experiment with 3 cycles. The possible mechanism to enhance the photocatalytic behavior is attributed to the expanded light absorption range, reduced surface migration resistance, and inhibited recombination of photo-generated electron and hole pairs. Graphical abstract
{"title":"Synthesis of Bi6O6(OH)3(NO3)3·1.5H2O/ZnO composite material with excellent photocatalytic hydrogen production performance","authors":"Lingyi Wang, Shichang Sun, Ziqing Zhong, Qingguang Gong, Xingpeng Jiang, Weiming Zhou, Liwei Wang, Ming-Yun Lin, Zhanhui Yuan","doi":"10.1080/19475411.2021.1933251","DOIUrl":"https://doi.org/10.1080/19475411.2021.1933251","url":null,"abstract":"ABSTRACT The heterojunction effect can effectively improve the separation efficiency of the photocatalyst’s photo-generated electron and hole pairs, thereby greatly improving the photocatalytic hydrogen production performance of the photocatalyst. In this paper, Bi6O6(OH)3(NO3)3 · 1.5H2O (BBN) and ZnO are used to construct and synthesize Bi6O6(OH)3(NO3)3 · 1.5H2O/ZnO (BBN/ZnO) heterojunction photocatalyst. Under UV-vis light irradiation, the BBN/ZnO composite could generate H2 with a rate of 28.66 μmol·g−1·h−1, which is higher than pure BBN (0.92 μmol·g−1·h−1) and ZnO (6.54 μmol·h−1·g−1) at around 31.1 and 4.4 times, respectively. Moreover, the experimental results found that the composite still exhibits excellent photocatalytic activity and maintains a high and stable activity in the 12-hour experiment with 3 cycles. The possible mechanism to enhance the photocatalytic behavior is attributed to the expanded light absorption range, reduced surface migration resistance, and inhibited recombination of photo-generated electron and hole pairs. Graphical abstract","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"185 - 197"},"PeriodicalIF":3.9,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1933251","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45765624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-03DOI: 10.1080/19475411.2021.1910874
Xiaowei Jiang, Zhi Wang, Shaowei Lu, Lu Zhang, Xiao Qiang Wang, Hao Zhang, Jian Lu, Bohan Li
ABSTRACT Fiber-reinforced resin-based plastics are widely used in structural composites for aerospace and automotive applications, and they often face extreme load conditions in actual working environments. It is challenging to monitor the damage of the structure during the vibration process. This study was aimed at using buckypaper (BP) sensors to monitor the structural health status of composite structures under ambient vibrations. First, the feasibility of flexible printed circuit instead of wire is verified by the tensile experiment. Then the vibration monitoring experiment of the composite cantilever beam is carried out by using BP sensors systematically. The sweep frequency experiment determines the excitation frequency of the cantilever beam. Low-period vibration fatigue cycle and high-period vibration fatigue cycle experiments are designed to verify the vibration monitoring method using BP sensors. Besides, the signal response of BP sensors in the vibration experiment is analyzed, and the relationship between ΔR/R0 and vibration acceleration is obtained. Finally, through the change law of ΔR/R0 of the sensor, the cumulative damage caused by vibration fatigue is visualized. It is demonstrated that the monitoring method based on BP sensors can be applied to study the damage behavior of composite structure under the vibration environment. Abbreviations: FRP, fiber-reinforced resin-based plastics; SHM, structural health monitoring; SEM, scanning electron microscopic; FPC, flexible printed circuit; FBG, Fiber Bragg Grating; AE, acoustic emission. Graphical abstract
{"title":"Vibration monitoring for composite structures using buckypaper sensors arrayed by flexible printed circuit","authors":"Xiaowei Jiang, Zhi Wang, Shaowei Lu, Lu Zhang, Xiao Qiang Wang, Hao Zhang, Jian Lu, Bohan Li","doi":"10.1080/19475411.2021.1910874","DOIUrl":"https://doi.org/10.1080/19475411.2021.1910874","url":null,"abstract":"ABSTRACT Fiber-reinforced resin-based plastics are widely used in structural composites for aerospace and automotive applications, and they often face extreme load conditions in actual working environments. It is challenging to monitor the damage of the structure during the vibration process. This study was aimed at using buckypaper (BP) sensors to monitor the structural health status of composite structures under ambient vibrations. First, the feasibility of flexible printed circuit instead of wire is verified by the tensile experiment. Then the vibration monitoring experiment of the composite cantilever beam is carried out by using BP sensors systematically. The sweep frequency experiment determines the excitation frequency of the cantilever beam. Low-period vibration fatigue cycle and high-period vibration fatigue cycle experiments are designed to verify the vibration monitoring method using BP sensors. Besides, the signal response of BP sensors in the vibration experiment is analyzed, and the relationship between ΔR/R0 and vibration acceleration is obtained. Finally, through the change law of ΔR/R0 of the sensor, the cumulative damage caused by vibration fatigue is visualized. It is demonstrated that the monitoring method based on BP sensors can be applied to study the damage behavior of composite structure under the vibration environment. Abbreviations: FRP, fiber-reinforced resin-based plastics; SHM, structural health monitoring; SEM, scanning electron microscopic; FPC, flexible printed circuit; FBG, Fiber Bragg Grating; AE, acoustic emission. Graphical abstract","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"198 - 217"},"PeriodicalIF":3.9,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1910874","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45025618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-29DOI: 10.1080/19475411.2021.1901791
Zengyao Lv, Xiaoyu Zhang, Honglong Zhang, Zhitao Zhou, Duo Xu, Y. Pei
ABSTRACT As an ideal high-density storage unit, magnetic nanorings have become a research hotspot in recent years. We can both study the evolution of microscopic state of magnetization and acquire macroscopic magnetic properties by micromagnetic simulation, which has thus been widely used. However, traditional micromagnetism cannot simulate complex stress state. Due to the introduction of microelasticity theory, the phase field method for magnetic materials can be used to calculate the coupling effect of stress and magnetic field. However, the computing model usually needs to satisfy periodic boundary condition. In this paper, the phase field simulation combined with the finite element method is employed. By using user defined element, the evolution of magnetic domain structures of the double-hole nanorings has been studied. In different diameter of the holes and external magnetic field direction, we have found seven kinds of magnetic domain evolution mechanism. Among them, the twin-vortex evolution mechanism with high stability and low demagnetization interference characteristics of advantages, has good application prospect in magnetic random-access memory (MRAM) unit. Graphical Abstract
{"title":"Phase-field simulation of magnetic double-hole nanoring and its application in random storage","authors":"Zengyao Lv, Xiaoyu Zhang, Honglong Zhang, Zhitao Zhou, Duo Xu, Y. Pei","doi":"10.1080/19475411.2021.1901791","DOIUrl":"https://doi.org/10.1080/19475411.2021.1901791","url":null,"abstract":"ABSTRACT As an ideal high-density storage unit, magnetic nanorings have become a research hotspot in recent years. We can both study the evolution of microscopic state of magnetization and acquire macroscopic magnetic properties by micromagnetic simulation, which has thus been widely used. However, traditional micromagnetism cannot simulate complex stress state. Due to the introduction of microelasticity theory, the phase field method for magnetic materials can be used to calculate the coupling effect of stress and magnetic field. However, the computing model usually needs to satisfy periodic boundary condition. In this paper, the phase field simulation combined with the finite element method is employed. By using user defined element, the evolution of magnetic domain structures of the double-hole nanorings has been studied. In different diameter of the holes and external magnetic field direction, we have found seven kinds of magnetic domain evolution mechanism. Among them, the twin-vortex evolution mechanism with high stability and low demagnetization interference characteristics of advantages, has good application prospect in magnetic random-access memory (MRAM) unit. Graphical Abstract","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"157 - 184"},"PeriodicalIF":3.9,"publicationDate":"2021-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1901791","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44692153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/19475411.2021.1880491
Saurav Sharma, Rajeev Kumar, R. Vaish
ABSTRACT Flexoelectricity is a symmetry independent electromechanical coupling phenomenon that outperforms piezoelectricity at micro and nanoscales due to its size-dependent behavior arising from gradient terms in its constitutive relations. However, due to this gradient term flexoelectricity, to exhibit itself, requires specially designed geometry or material composition of the dielectric material. First of its kind, the present study put forward a novel strategy of achieving electric field gradient and thereby converse flexoelectricity, independent of geometry and material composition of the material. The spatial variation of the electric field is established inside the dielectric material, Ba0.67Sr0.33TiO3 (BST), by manipulating electrical boundary conditions. Three unique patterns of electrode placement are suggested to achieve this spatial variation. This varying direction of electric field gives rise to electric field gradient, the prerequisite of converse flexoelectricity. A multi-physics coupling based theoretical framework is established to solve the flexoelectric actuation by employing isogeometric analysis (IGA). Electromechanically coupled equations of flexoelectricity are solved to obtain the electric field distribution and the resulting displacements thereby. The maximum displacements of 0.2 nm and 2.36 nm are obtained with patterns I and II, respectively, while pattern III can yield up to 85 nm of maximum displacement. Graphical abstarct
{"title":"Universal converse flexoelectricity in dielectric materials via varying electric field direction","authors":"Saurav Sharma, Rajeev Kumar, R. Vaish","doi":"10.1080/19475411.2021.1880491","DOIUrl":"https://doi.org/10.1080/19475411.2021.1880491","url":null,"abstract":"ABSTRACT Flexoelectricity is a symmetry independent electromechanical coupling phenomenon that outperforms piezoelectricity at micro and nanoscales due to its size-dependent behavior arising from gradient terms in its constitutive relations. However, due to this gradient term flexoelectricity, to exhibit itself, requires specially designed geometry or material composition of the dielectric material. First of its kind, the present study put forward a novel strategy of achieving electric field gradient and thereby converse flexoelectricity, independent of geometry and material composition of the material. The spatial variation of the electric field is established inside the dielectric material, Ba0.67Sr0.33TiO3 (BST), by manipulating electrical boundary conditions. Three unique patterns of electrode placement are suggested to achieve this spatial variation. This varying direction of electric field gives rise to electric field gradient, the prerequisite of converse flexoelectricity. A multi-physics coupling based theoretical framework is established to solve the flexoelectric actuation by employing isogeometric analysis (IGA). Electromechanically coupled equations of flexoelectricity are solved to obtain the electric field distribution and the resulting displacements thereby. The maximum displacements of 0.2 nm and 2.36 nm are obtained with patterns I and II, respectively, while pattern III can yield up to 85 nm of maximum displacement. Graphical abstarct","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"107 - 128"},"PeriodicalIF":3.9,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1880491","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45469987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/19475411.2021.1885081
Wentao Su, Chunhua Zhu, Anping Hua, Shanchen Li, Junhua Zhao
ABSTRACT Nanoscale defects, including cracks, circular holes, and the triangular-shaped defects, often occur in the growth of boron nitride nanosheets (BNNS). In this study, the fracture behavior of chiral BNNS with different crack-tip shapes and the interactions of nanoscale crack-defects are studied using molecular dynamics (MD) simulations and finite element (FE) analysis. Both MD and FE results indicate that the fracture strength of BNNS with two crack tips (t = 2) is significantly higher than that with one crack tip (t = 1), in which the difference in zigzag (ZZ) direction is more obvious than that in armchair (AC) direction, mainly due to the fact that the change of bond angles near the crack tips is more substantial in the ZZ direction than those in the AC direction. Our results show that the fracture strength of BNNS strongly depends on crack-tip shapes, chiral angles, the defect-to-crack tip spacing and deflection angles. Checking against the current MD simulations and FE analysis shows the present results are reasonable. This study should be of great importance for enhancing the fracture performance of BNNS by modulating their crack-tip shapes and the interactions of nanoscale crack-defects. Graphical abstract
{"title":"Fracture behavior dependent on crack-tip shapes in nanoscale crack-defect monolayer boron nitride sheets","authors":"Wentao Su, Chunhua Zhu, Anping Hua, Shanchen Li, Junhua Zhao","doi":"10.1080/19475411.2021.1885081","DOIUrl":"https://doi.org/10.1080/19475411.2021.1885081","url":null,"abstract":"ABSTRACT Nanoscale defects, including cracks, circular holes, and the triangular-shaped defects, often occur in the growth of boron nitride nanosheets (BNNS). In this study, the fracture behavior of chiral BNNS with different crack-tip shapes and the interactions of nanoscale crack-defects are studied using molecular dynamics (MD) simulations and finite element (FE) analysis. Both MD and FE results indicate that the fracture strength of BNNS with two crack tips (t = 2) is significantly higher than that with one crack tip (t = 1), in which the difference in zigzag (ZZ) direction is more obvious than that in armchair (AC) direction, mainly due to the fact that the change of bond angles near the crack tips is more substantial in the ZZ direction than those in the AC direction. Our results show that the fracture strength of BNNS strongly depends on crack-tip shapes, chiral angles, the defect-to-crack tip spacing and deflection angles. Checking against the current MD simulations and FE analysis shows the present results are reasonable. This study should be of great importance for enhancing the fracture performance of BNNS by modulating their crack-tip shapes and the interactions of nanoscale crack-defects. Graphical abstract","PeriodicalId":48516,"journal":{"name":"International Journal of Smart and Nano Materials","volume":"12 1","pages":"36 - 48"},"PeriodicalIF":3.9,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/19475411.2021.1885081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48088604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/19475411.2021.1887396
J. Regis, Sebastian Vargas, Andrea Irigoyen, Elsa Bramasco-Rivera, J. Bañuelos, Luis Delfin, A. Renteria, Ulises Martinez, T. Rockward, Yirong Lin
ABSTRACT Recent studies have highlighted the effects of various stimuli on the chemical reduction of graphene oxide (GO) through green reductant L-ascorbic acid (L-AA); however, the combination of near ultraviolet (NUV) light to increase the reduction rate has yet to be thoroughly explored. In this study, drop-casted GO films were subjected to chemical reduction through L-AA with various levels of exposure under 405 nm NUV radiation. The structure and uniformity of GO stackings that form the film were characterized through scanning electron microscopy (SEM) and wide-angle x-ray scattering (WAXS). Additionally, WAXS was used to track the removal of oxygen-containing functional groups along with Fourier-transform infrared (FT-IR) spectroscopy and x-ray photoelectron spectroscopy (XPS) as a function of L-AA and NUV light exposure times. XPS results demonstrated that the interaction between L-AA and NUV exposure has a significant effect on the reduction of films. Furthermore, the results that yielded the highest reduction (C-C bond concentration of 60.7%) were the longest L-AA and NUV light exposure times (48 hours and 3 hours, respectively). This report provides a study on the effects of NUV on the green reduction of GO films through L-AA with potential application in solar energy and chemical sensing applications. Graphical abstract
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