Mechanical and Electrostrictive Effects in Anodic Films

Proost, Joris

doi:10.1016/b978-0-12-409547-2.13403-1

Cited by 3 publications

(7 citation statements)

References 78 publications

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“…Therefore, we showed in Figure b the electric fields that produce up to the maximum bending angle, which does not mean that this is the value of breakdown strength in this case. When applying an electric field through the thickness of a highly polar elastomer, two forces were generated due to the electrostriction effect. − The first one is due to the columbic attraction between the opposite charges on both sides of the elastomer film, Columbic forces. The second is the force due to the alignment of the dipoles in the opposite direction of the respective electrodes.…”

Section: Resultsmentioning

confidence: 91%

“…The resultant force, in the case of our elastomers, leads to a novel out-of-plane bending behavior without the need to prestretch the elastomer film or without attaching a passive layer to the elastomer surface, , as shown in Figure b. Although, in the literature, actuation without prestretch has been referred to the suppression of the electromechanical instability due to the mechanical behavior of the elastomers, , the investigated theoretical models regarding the dielectrics with high permittivity could help here to explain our deformation mechanism. ,, …”

Section: Resultsmentioning

confidence: 91%

“…Summary of the Dielectric and Mechanical Properties of the Investigated Elastomers with high permittivity could help here to explain our deformation mechanism. 64,65,67 Furthermore, we have designed an experiment to understand the full phenomena of this novel bending without prestretching and without attaching a passive layer. First, we noted that the elastomers always bend to the side of the positive electrode.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…However, the full understanding of this phenomenon is still not fully investigated. Some models in the literature showed that under the electric field, dielectrics with high density of dipoles have a complex induced stress due to the Maxwell effect and the dipole alignment, which may result in out-of-plane deformation to a certain side in soft dielectric elastomers. − …”

Section: Resultsmentioning

confidence: 99%

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Programmable, UV-Printable Dielectric Elastomers Actuate at Low Voltage without Prestretch and Supporting Frames

Borayek

Zhang

Willy

et al. 2020

ACS Appl. Electron. Mater.

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Dielectric elastomers are soft and perfect insulator polymers able to produce large strains with high energy density under the effect of applied high voltage. However, their use in practical applications is hindered by the need for high voltage to actuate. Also, they need prestretching between rigid frames to produce out-of-plane shape changes, which may reduce their lifetime. Here, we synthesized a set of elastomers with high permittivity (from 20 to reach 60 at 10 3 Hz), controllable thermal properties (T g vary from −15 to −50 °C), and good mechanical properties (Young's modulus values between 0.48 and 0.2 MPa at 20% strain). Due to the high permittivity, an actuator made of the material was able to respond to a low voltage of 700 V and produce a 6.5% area strain for more than 10 000 cycles. Moreover, the elastomers were found to produce giant free-end bending displacements with prespecified bending direction (bend to the side of the positive electrode) under a low electric field, which we called programmable dielectric elastomers (PDE). Besides the aforementioned characteristics and performance, the formulated elastomers are suitable for UV-based three-dimensional (3D) printing. The printability of the elastomers allows fabricating programmable complex geometries to produce high deformations under relatively low electric fields.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 91%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Programmable, UV-Printable Dielectric Elastomers Actuate at Low Voltage without Prestretch and Supporting Frames

Borayek

Zhang

Willy

et al. 2020

ACS Appl. Electron. Mater.

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“…They also concluded that a larger accumulated negative charge results in a higher rate of anodic oxide growth. These negative charges are likely electrons trapped by structural defects created by mechanical stress induced by the incorporation of impurities during film growth [ 8 , 38 , 45 ], as well as the ionisation of water molecules, yielding electrons, protons, and gaseous oxygen [ 46 ].…”

Section: Resultsmentioning

confidence: 99%

Isotopic Tracer Study of Initiation of Porosity in Anodic Alumina Formed in Chromic Acid

Baron-Wiechec,

Lin

2023

Nanomaterials

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In this paper, we focused on the initiation of porosity in the anodic alumina under galvanostatic conditions in chromic acid, using an 18O isotope tracer. The general concept of the initiation and growth of porous anodic oxide films on metals has undergone constant development over many years. A mechanism of viscous flow of the oxide from the barrier layer to the pore walls has recently been proposed. In this work, two types of pre-formed oxide films were analysed: pure Al2O3 formed in chromic acid, and a film containing As ions formed in a sodium arsenate solution. Both were anodized in chromic acid for several different time durations. Both pre-formed films contained the oxygen isotope 18O. The locations and quantities of 18O and As were analysed by means of ion accelerator-based methods supported by transmission electron microscopy. The significant difference observed between the two oxide films is in the 18O distribution following the second step of anodization, when compared with galvanostatic anodization in phosphoric or sulfuric acid reported in previous works. From the current experiment, it is evident that a small amount of As in the pre-formed barrier layer appears to alter the ionic conductivity of the film; thus, somehow, it inhibits the movement of oxygen ions ahead of advancing pores during anodization in chromic acid. However, anodising pure alumina film under these conditions does not enhance oxygen movement within the oxide layer. In addition, the tracer stays in the outer part of the growing porous oxide film. A lower-than-expected value for pure alumina enrichment in 18O in the pre-formed films suggests, indirectly, that the pre-formed film may contain hydrogen species, as well as trapped electrons, since no Cr is detected. This may lead to the presence of space charge distribution, which has a dual effect: it both retards the ejection of Al3+ ions and prevents O2− ions from migrating inward. Thus, the negative- and positive-charge distributions might play a role in the initiation of pores via a flow mechanism.

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Wear and micromechanical performance of novel mono/bi-layered PVD-coated WC tools in high-speed turning of Ti-5Al-5V-5Mo-3Cr alloy

Syed,

De Paiva,

Veldhuis

2024

Int J Adv Manuf Technol

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Mechanical and Electrostrictive Effects in Anodic Films

Cited by 3 publications

References 78 publications

Programmable, UV-Printable Dielectric Elastomers Actuate at Low Voltage without Prestretch and Supporting Frames

Programmable, UV-Printable Dielectric Elastomers Actuate at Low Voltage without Prestretch and Supporting Frames

Isotopic Tracer Study of Initiation of Porosity in Anodic Alumina Formed in Chromic Acid

Wear and micromechanical performance of novel mono/bi-layered PVD-coated WC tools in high-speed turning of Ti-5Al-5V-5Mo-3Cr alloy

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