24 research outputs found
Construction of a Fish-like Robot Based on High Performance Graphene/PVDF Bimorph Actuation Materials.
Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish-like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene-PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene-based materials at a macro scale
Highly Reusable and Environmentally Friendly Solid Fuel Material Based on Three-Dimensional Graphene Foam
It
is a great challenge to find a reusable solid fuel material
with both high absorption capability for organic liquids and clean
use. In this work, a highly reusable and environmentally friendly
solid fuel material based on three-dimensional graphene foam (3D-GF)
was prepared, with high absorption capability for organic liquid fuels
up to over 900 times its own weight and outstanding fire resistance.
This 3D-GF shows high combustion efficiency, exceeding 99%. A rather
clean burning was observed without toxic gases and soot particles
released, as in the case of the conventional solid fuel materials.
More importantly, the reusability and mechanical stability of the
material are kept almost unchanged after 10 cycles of adsorption–combustion
with organic liquid fuels
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Construction of a Fish-like Robot Based on High Performance Graphene/PVDF Bimorph Actuation Materials.
Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish-like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene-PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene-based materials at a macro scale
Construction of a Fish‐like Robot Based on High Performance Graphene/PVDF Bimorph Actuation Materials
Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish‐like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene‐PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene‐based materials at a macro scale
Facile Fabrication of Binary Nanoscale Interface for No-Loss Microdroplet Transportation
Binary
nanoscale interfacial materials are fundamental issues in
many applications for smart surfaces. A binary nanoscale interface
with binary surface morphology and binary wetting behaviors has been
prepared by a facile wet-chemical method. The prepared surface presents
superhydrophobicity and high adhesion with the droplet at the same
time. The composition, surface morphology, and wetting behaviors of
the prepared surface have been systematic studied. The special wetting
behaviors can be contributed to the binary nanoscale effect. The stability
of the prepared surface was also investigated. As a primary application,
a facile device based on the prepared binary nanoscale interface with
superhydrophobicity and high adhesion was constructed for microdroplet
transportation
Bioinspired Composite Coating with Extreme Underwater Superoleophobicity and Good Stability for Wax Prevention in the Petroleum Industry
Wax deposition is a detrimental problem
that happens during crude oil production and transportation, which
greatly reduces transport efficiency and causes huge economic losses.
To avoid wax deposition, a bioinspired composite coating with excellent
wax prevention and anticorrosion properties is developed in this study.
The prepared coating is composed of three films, including an electrodeposited
Zn film for improving corrosion resistance, a phosphating film for
constructing fish-scale morphology, and a silicon dioxide film modified
by a simple spin-coating method for endowing the surface with superhydrophilicity.
Good wax prevention performance has been investigated in a wax deposition
test. The surface morphology, composition, wetting behaviors, and
stability are systematically studied, and a wax prevention mechanism
is proposed, which can be calculated from water film theory. This
composite coating strategy which shows excellent properties in both
wax prevention and stability is expected to be widely applied in the
petroleum industry
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Super-elasticity of three-dimensionally cross-linked graphene materials all the way to deep cryogenic temperatures.
Until now, materials with high elasticity at deep cryogenic temperatures have not been observed. Previous reports indicated that graphene and carbon nanotube-based porous materials can exhibit reversible mechano-elastic behavior from liquid nitrogen temperature up to nearly a thousand degrees Celsius. Here, we report wide temperature-invariant large-strain super-elastic behavior in three-dimensionally cross-linked graphene materials that persists even to a liquid helium temperature of 4 K, a property not previously observed for any other material. To understand the mechanical properties of these graphene materials, we show by in situ experiments and modeling results that these remarkable properties are the synergetic results of the unique architecture and intrinsic elastic/flexibility properties of individual graphene sheets and the covalent junctions between the sheets that persist even at harsh temperatures. These results suggest possible applications for such materials at extremely low temperature environments such as those in outer space
Preparation of Ultra-Smooth Cu Surface for High-Quality Graphene Synthesis
Abstract As grown graphene by chemical vapor deposition typically degrades greatly due to the presence of grain boundaries, which limit graphene’s excellent properties and integration into advanced applications. It has been demonstrated that there is a strong correlation between substrate morphology and graphene domain density. Here, we investigate how thermal annealing and electro-polishing affects the morphology of Cu foils. Ultra-smooth Cu surfaces can be achieved and maintained at elevated temperatures by electro-polishing after a pre-annealing treatment. This technique has shown to be more effective than just electro-polishing the Cu substrate without pre-annealing. This may be due to the remaining dislocations and point defects within the Cu bulk material moving to the surface when the Cu is heated. Likewise, a pre-annealing step may release them. Graphene grown on annealed electro-polished Cu substrates show a better quality in terms of lower domain density and higher layer uniformity than those grown on Cu substrates with only annealing or only electro-polishing treatment
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Super-elasticity of three-dimensionally cross-linked graphene materials all the way to deep cryogenic temperatures.
Until now, materials with high elasticity at deep cryogenic temperatures have not been observed. Previous reports indicated that graphene and carbon nanotube-based porous materials can exhibit reversible mechano-elastic behavior from liquid nitrogen temperature up to nearly a thousand degrees Celsius. Here, we report wide temperature-invariant large-strain super-elastic behavior in three-dimensionally cross-linked graphene materials that persists even to a liquid helium temperature of 4 K, a property not previously observed for any other material. To understand the mechanical properties of these graphene materials, we show by in situ experiments and modeling results that these remarkable properties are the synergetic results of the unique architecture and intrinsic elastic/flexibility properties of individual graphene sheets and the covalent junctions between the sheets that persist even at harsh temperatures. These results suggest possible applications for such materials at extremely low temperature environments such as those in outer space