An advanced electro-active dry adhesive, which was composed of a mushroom-shaped tibrillar dry adhesive array actuated by an Ionic Polymer Metal Composite （IPMC） artificial muscle reinforced with nitrogen-doped carb...An advanced electro-active dry adhesive, which was composed of a mushroom-shaped tibrillar dry adhesive array actuated by an Ionic Polymer Metal Composite （IPMC） artificial muscle reinforced with nitrogen-doped carbon nanocages （NCNCs）, was developed to imitate the actuation of a gecko＇s toe. The properties of the NCNC-reinforced Nation membrane, the electro- mechanical properties of the NCNC-reinforced IPMC, and the related electro-active adhesion ability were investigated. The NCNCs were uniformly dispersed in the 0.1 wt% NCNC/Nafion membrane, and there was a seamless connection with no clear interface between the dry adhesive and the IPMC. Our 0.1 wt% NCNC/Nation-IPMC actuator shows a displacement and force that are 1.6 - 2 times higher than those of the recast Nafion-IPMC. This is due to the increased water uptake （25.39%） and tensile strength （24.5 MPa） of the specific 3D hollow NCNC-reinforced Nation membrane, as well as interactions between the NCNCs and the sulfonated groups of the Nation. The NCNC/Nation-IPMC was used to effectively actuate the mushroom-shaped dry adhesive. The normal adhesion forces were 7.85 raN, 12.1 mN, and 51.7 mN at sinusoidal voltages of 1.5 V, 2.5 V, and 3.5 V, respectively, at 0.1 Hz. Under the bionic leg trail, the normal and shear forces were approximately 713.5 mN （159 mN·cm^-2） and 1256.6 mN （279 mN·cm^-2）, respectively, which satisfy the required adhesion. This new electro-active dry adhesive can be applied for active, distributed actuation and flexible grip in robots.展开更多
Smart Materials are along with Innovation attributes and Artificial Intelligence among the most used “buzz” words in all media. Central to their practical occurrence, many talents are to be gathered within new conte...Smart Materials are along with Innovation attributes and Artificial Intelligence among the most used “buzz” words in all media. Central to their practical occurrence, many talents are to be gathered within new contextual data influxes. Has this, in the last 20 years, changed some of the essential fundamental dimensions and the required skills of the actors such as providers, users, insiders, etc.? This is a preliminary focus and prelude of this review. As an example, polysaccharide materials are the most abundant macromolecules present as an integral part of the natural system of our planet. They are renewable, biodegradable, carbon neutral with low environmental, health and safety risks and serve as structural materials in the cell walls of plants. Most of them are used, for many years, as engineering materials in many important industrial processes, such as pulp and papermaking and manufacture of synthetic textile fibres. They are also used in other domains such as conversion into biofuels and, more recently, in the design of processes using polysaccharide nanoparticles. The main properties of polysaccharides (e.g. low density, thermal stability, chemical resistance, high mechanical strength…), together with their biocompatibility, biodegradability, functionality, durability and uniformity, allow their use for manufacturing smart materials such as blends and composites, electroactive polymers and hydrogels which can be obtained 1) through direct utilization and/or 2) after chemical or physical modifications of the polysaccharides. This paper reviews recent works developed on polysaccharides, mainly on cellulose, hemicelluloses, chitin, chitosans, alginates, and their by-products (blends and composites), with the objectives of manufacturing smart materials. It is worth noting that, today, the fundamental understanding of the molecular level interactions that confer smartness to polysaccharides remains poor and one can predict that new experimental and theoretical tools will emerge to develop the necessary 展开更多
Organometallic conjugated complexes have become an important type of stimuli-responsive materials because of their appealing electrochemical properties and rich photonic, electronic, and magnetic properties. They are ...Organometallic conjugated complexes have become an important type of stimuli-responsive materials because of their appealing electrochemical properties and rich photonic, electronic, and magnetic properties. They are potentially useful in a wide range of applications such as molecular wires, molecular switches, molecular machines, molecular memory, and optoelectronic detections. This review outlines the recent progress on the molecular design of carbometalated ruthenium and osmium complexes and their applications as redox-responsive materials with visible and near-infrared(NIR) absorptions and electron paramagnetic resonance as readout signals. Three molecule systems are introduced, including the symmetric diruthenium complexes, metal-amine conjugated bi-center system, and multi-center redox-active organometallic compounds. Because of the presence of a metal-carbon bond on each metal component and strong electronic coupling between redox sites, these compounds display multiple reversible redox processes at low potentials and each redox state possesses significantly different physical and chemical properties. Using electrochemical potentials as input signals, these materials show reversible NIR absorption spectral changes, making them potentially useful in NIR electrochromism and information storage.展开更多
The development of hydrogen-bonded organic frameworks(HOFs) with predictable topologies and robust structures for targeted functionality was initially hindered by the relatively weak H-bonding interactions as many HOF...The development of hydrogen-bonded organic frameworks(HOFs) with predictable topologies and robust structures for targeted functionality was initially hindered by the relatively weak H-bonding interactions as many HOFs would collapse upon guest solvent removal. Recently, the design of tectons with large π-conjugated systems that form intermolecular shape-fitted π-πstacking interactions has proven to be an effective strategy to create chemically and thermally stable HOFs. More importantly,these HOFs with large π-conjugated tectons exhibit accelerated redox hopping processes due to more favorable through-space orbital overlap interactions. These intrinsic photoelectric properties render HOFs an appealing and unique class of photoactive and electroactive porous materials for catalysis, sensing, and biomedical applications. Based on shape-fitted π-π stacking strategy, various robust photoactive and electroactive HOFs have been built from tectons containing both photosensitive or redox-active organic cores and hydrogen bonding sites. This review summarizes the recent advancements, including synthetic methods and diverse applications, in the development of photo-and electro-active HOFs. Considering the numerous photo-and electro-active organic units available, as well as the virtually unlimited potential combinations of organic cores and hydrogen bonding sites, we anticipate that this review will inspire scientists in a range of disciplines, ranging from porous materials to organic photoelectric materials and catalysis scientists, to further explore functional photo-and electro-active HOF materials.展开更多
Based on the theories of finite deformation elasticity, electromechanical responses and instability of an incompressible electro-active polymer （EAP） cylindrical shell, which is subjected to an internal pressure and...Based on the theories of finite deformation elasticity, electromechanical responses and instability of an incompressible electro-active polymer （EAP） cylindrical shell, which is subjected to an internal pressure and a static electric field, are studied. Deformation curves and distribution of stresses are obtained. It is found that an internal pressure together with an electric field may cause the unstable non-monotonic deforma- tion of the shell. It is also shown that a critical thickness for the shell exists, and the shell may undergo the unstable deformation if its thickness is less than this critical value. In addition, the effects of the electric field, axial stretch, thickness, and internal pressure on the instability of the shell are discussed.展开更多
Direct piezoelectricity of electro-active papers （EAPap） is analysed in this paper. The test setups for direct effect are designed and determined. Different ambient factors impacting the piezoelectricity of EAPap, s...Direct piezoelectricity of electro-active papers （EAPap） is analysed in this paper. The test setups for direct effect are designed and determined. Different ambient factors impacting the piezoelectricity of EAPap, such as temperature, humidity, and strain rate, are applied and analyzed. Strong piezoelectricity of EAPap is found on the basis of the test results and in comparison with polyvinylidene fluoride （PVDF） and lead zirconate titanate （PZT）-5H. The maximum piezoelectric constant is achieved to be 504 pC/N. The reason of strong piezoelectricity of EAPap is discussed in this paper. The potential of EAPap as a biomimetic actuator and sensor is also investigated.展开更多
As a novel piezoelectric material, the mechanical and piezoelectric properties of cellulose electro-active paper (EAPap) were studied. Young's modulus of piezoelectric EAPap was dependant on the material orientati...As a novel piezoelectric material, the mechanical and piezoelectric properties of cellulose electro-active paper (EAPap) were studied. Young's modulus of piezoelectric EAPap was dependant on the material orientation as compared with other EAP materials. The highest Young's modulus was obtained at 0° direction, while the highest direct piezoelectric charge constant was achieved at 45°. By measuring the induced output voltage from the thin piezoelectric cellulose film under the applied impact force, we demonstrate that piezoelectric EAPap film has a potential for sensor applications.展开更多
基金This work was partially supported by the National Natural Science Foundation of China （Grant Nos. 51605220, U1637101, 51435008）, the Natural Science Foundation of Jiangsu Province （Grant No. BK20160793）, the High Level Introduction of Talent Research Start-up Fund in NUAA （Grant No. 1011-YAH16010）, and Open Project Fund in Jiangsu Provincial Key Laboratory for Interventional Medical Devices （Grant No. jr1601）. The authors would very much like to thank Professor Stanislav N. Gorb in the Department of Functional Morphology and Biome- chanics in the Zoological Institute of the University of Kiel, Germany, for his help with the mushroom-shapeddry adhesives, and also thank Dr. Yajun Xue and Miss Yan Ding for help with the SEM observations.
文摘An advanced electro-active dry adhesive, which was composed of a mushroom-shaped tibrillar dry adhesive array actuated by an Ionic Polymer Metal Composite （IPMC） artificial muscle reinforced with nitrogen-doped carbon nanocages （NCNCs）, was developed to imitate the actuation of a gecko＇s toe. The properties of the NCNC-reinforced Nation membrane, the electro- mechanical properties of the NCNC-reinforced IPMC, and the related electro-active adhesion ability were investigated. The NCNCs were uniformly dispersed in the 0.1 wt% NCNC/Nafion membrane, and there was a seamless connection with no clear interface between the dry adhesive and the IPMC. Our 0.1 wt% NCNC/Nation-IPMC actuator shows a displacement and force that are 1.6 - 2 times higher than those of the recast Nafion-IPMC. This is due to the increased water uptake （25.39%） and tensile strength （24.5 MPa） of the specific 3D hollow NCNC-reinforced Nation membrane, as well as interactions between the NCNCs and the sulfonated groups of the Nation. The NCNC/Nation-IPMC was used to effectively actuate the mushroom-shaped dry adhesive. The normal adhesion forces were 7.85 raN, 12.1 mN, and 51.7 mN at sinusoidal voltages of 1.5 V, 2.5 V, and 3.5 V, respectively, at 0.1 Hz. Under the bionic leg trail, the normal and shear forces were approximately 713.5 mN （159 mN·cm^-2） and 1256.6 mN （279 mN·cm^-2）, respectively, which satisfy the required adhesion. This new electro-active dry adhesive can be applied for active, distributed actuation and flexible grip in robots.
文摘Smart Materials are along with Innovation attributes and Artificial Intelligence among the most used “buzz” words in all media. Central to their practical occurrence, many talents are to be gathered within new contextual data influxes. Has this, in the last 20 years, changed some of the essential fundamental dimensions and the required skills of the actors such as providers, users, insiders, etc.? This is a preliminary focus and prelude of this review. As an example, polysaccharide materials are the most abundant macromolecules present as an integral part of the natural system of our planet. They are renewable, biodegradable, carbon neutral with low environmental, health and safety risks and serve as structural materials in the cell walls of plants. Most of them are used, for many years, as engineering materials in many important industrial processes, such as pulp and papermaking and manufacture of synthetic textile fibres. They are also used in other domains such as conversion into biofuels and, more recently, in the design of processes using polysaccharide nanoparticles. The main properties of polysaccharides (e.g. low density, thermal stability, chemical resistance, high mechanical strength…), together with their biocompatibility, biodegradability, functionality, durability and uniformity, allow their use for manufacturing smart materials such as blends and composites, electroactive polymers and hydrogels which can be obtained 1) through direct utilization and/or 2) after chemical or physical modifications of the polysaccharides. This paper reviews recent works developed on polysaccharides, mainly on cellulose, hemicelluloses, chitin, chitosans, alginates, and their by-products (blends and composites), with the objectives of manufacturing smart materials. It is worth noting that, today, the fundamental understanding of the molecular level interactions that confer smartness to polysaccharides remains poor and one can predict that new experimental and theoretical tools will emerge to develop the necessary
基金supported by the National Natural Science Foundation of China(21271176,21472196,21521062,21501183)the Ministry of Science and Technology of China(2012YQ120060)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB 12010400)
文摘Organometallic conjugated complexes have become an important type of stimuli-responsive materials because of their appealing electrochemical properties and rich photonic, electronic, and magnetic properties. They are potentially useful in a wide range of applications such as molecular wires, molecular switches, molecular machines, molecular memory, and optoelectronic detections. This review outlines the recent progress on the molecular design of carbometalated ruthenium and osmium complexes and their applications as redox-responsive materials with visible and near-infrared(NIR) absorptions and electron paramagnetic resonance as readout signals. Three molecule systems are introduced, including the symmetric diruthenium complexes, metal-amine conjugated bi-center system, and multi-center redox-active organometallic compounds. Because of the presence of a metal-carbon bond on each metal component and strong electronic coupling between redox sites, these compounds display multiple reversible redox processes at low potentials and each redox state possesses significantly different physical and chemical properties. Using electrochemical potentials as input signals, these materials show reversible NIR absorption spectral changes, making them potentially useful in NIR electrochromism and information storage.
基金the financial support from the start-up fund of Fudan Universitythe Northwestern University International Institute for Nanotechnology。
文摘The development of hydrogen-bonded organic frameworks(HOFs) with predictable topologies and robust structures for targeted functionality was initially hindered by the relatively weak H-bonding interactions as many HOFs would collapse upon guest solvent removal. Recently, the design of tectons with large π-conjugated systems that form intermolecular shape-fitted π-πstacking interactions has proven to be an effective strategy to create chemically and thermally stable HOFs. More importantly,these HOFs with large π-conjugated tectons exhibit accelerated redox hopping processes due to more favorable through-space orbital overlap interactions. These intrinsic photoelectric properties render HOFs an appealing and unique class of photoactive and electroactive porous materials for catalysis, sensing, and biomedical applications. Based on shape-fitted π-π stacking strategy, various robust photoactive and electroactive HOFs have been built from tectons containing both photosensitive or redox-active organic cores and hydrogen bonding sites. This review summarizes the recent advancements, including synthetic methods and diverse applications, in the development of photo-and electro-active HOFs. Considering the numerous photo-and electro-active organic units available, as well as the virtually unlimited potential combinations of organic cores and hydrogen bonding sites, we anticipate that this review will inspire scientists in a range of disciplines, ranging from porous materials to organic photoelectric materials and catalysis scientists, to further explore functional photo-and electro-active HOF materials.
基金Project supported by the National Natural Science Foundation of China(No.10772104)the Shanghai Leading Academic Discipline Project(No.S30106)
文摘Based on the theories of finite deformation elasticity, electromechanical responses and instability of an incompressible electro-active polymer （EAP） cylindrical shell, which is subjected to an internal pressure and a static electric field, are studied. Deformation curves and distribution of stresses are obtained. It is found that an internal pressure together with an electric field may cause the unstable non-monotonic deforma- tion of the shell. It is also shown that a critical thickness for the shell exists, and the shell may undergo the unstable deformation if its thickness is less than this critical value. In addition, the effects of the electric field, axial stretch, thickness, and internal pressure on the instability of the shell are discussed.
文摘Direct piezoelectricity of electro-active papers （EAPap） is analysed in this paper. The test setups for direct effect are designed and determined. Different ambient factors impacting the piezoelectricity of EAPap, such as temperature, humidity, and strain rate, are applied and analyzed. Strong piezoelectricity of EAPap is found on the basis of the test results and in comparison with polyvinylidene fluoride （PVDF） and lead zirconate titanate （PZT）-5H. The maximum piezoelectric constant is achieved to be 504 pC/N. The reason of strong piezoelectricity of EAPap is discussed in this paper. The potential of EAPap as a biomimetic actuator and sensor is also investigated.
基金Supported by the Korea Research Foundation Grant (KRF-2008-314-D00009)Creative Research Initiative (EAPap Actuator) of KOSEF/MEST in South Korea
文摘As a novel piezoelectric material, the mechanical and piezoelectric properties of cellulose electro-active paper (EAPap) were studied. Young's modulus of piezoelectric EAPap was dependant on the material orientation as compared with other EAP materials. The highest Young's modulus was obtained at 0° direction, while the highest direct piezoelectric charge constant was achieved at 45°. By measuring the induced output voltage from the thin piezoelectric cellulose film under the applied impact force, we demonstrate that piezoelectric EAPap film has a potential for sensor applications.
