Special Issue "Innovative Processing Routes for Electroactive Materials"

A special issue of Ceramics (ISSN 2571-6131).

Deadline for manuscript submissions: 31 July 2021.

Special Issue Editor

Dr. Giuseppe Viola
E-Mail Website
Guest Editor
University College London, Institute for Materials Discovery, 113 Roberts Building, Malet Place, WC1E 7JE, London
Interests: functional materials; electroceramics; energy storage capacitors; piezoelectric devices

Special Issue Information

Dear Colleagues,

It is our pleasure to open submissions for the present Special Issue dedicated to innovative processing routes for the fabrication of electroactive materials, with specific focus on dielectrics, piezoelectrics, ferroelectrics, multiferroics and thermoelectrics. We invite original research contributions in the form of short communications, full-length articles and reviews to share and disseminate the latest developments on the processing of electroactive materials that enable overcoming the difficulties encountered using conventional methods and identifying appropriate processing schedules for the fabrication of novel materials. Technical manuscripts on powder technologies, synthesis procedures and novel sintering techniques, including cold sintering, flash sintering and current assisted sintering, as well as manufacturing routes for mass production that can support industrial-scale processing of novel materials, are considered particularly appropriate for this Special Issue. The main aim is to compile original and insightful papers that can guide materials scientists to solve major processing issues and obtain high-quality materials with desired properties.

Dr. Giuseppe Viola
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Ceramics is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Electroactive materials
  • Innovative manufacturing
  • Powder processing
  • Synthesis
  • Sintering
  • Microstructure
  • Electrical properties

Published Papers (2 papers)

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Research

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Open AccessArticle
Tunable Magneto-Dielectric Material for Electrically Small and Reconfigurable Antenna Systems at Vhf Band
Ceramics 2020, 3(3), 276-286; https://0-doi-org.brum.beds.ac.uk/10.3390/ceramics3030025 - 06 Jul 2020
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Abstract
The main issue to tune controlled devices by the application of a DC magnetic field comes up against the high value of the field’s intensity required for their implementation. This work presents an implementation of magneto-dielectric materials (MDM) specifically manufactured for their integration [...] Read more.
The main issue to tune controlled devices by the application of a DC magnetic field comes up against the high value of the field’s intensity required for their implementation. This work presents an implementation of magneto-dielectric materials (MDM) specifically manufactured for their integration in antenna devices operating in VHF band. The twofold objective is: (i) reduction in antenna size, (ii) frequency tuning of the antenna using a low intensity magnetic control. A notable permeability variation of MDM samples is observed when the symmetry of the lines of the control field, with an intensity less than 10 Oe, is consistent with the one of the structures in the magnetic domains. The MDM allows a miniaturization of 20% of an inverted-F antenna (IFA) antenna structure, and an agility of about 2.5% for a control field of 1.5 Oe. Full article
(This article belongs to the Special Issue Innovative Processing Routes for Electroactive Materials)
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Review

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Open AccessReview
The Role of Sacrificial and/or Protective Layers to Improve the Sintering of Electroactive Ceramics: Application to Piezoelectric PZT-Printed Thick Films for MEMS
Ceramics 2020, 3(4), 453-475; https://0-doi-org.brum.beds.ac.uk/10.3390/ceramics3040038 - 16 Nov 2020
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Abstract
Piezoelectric thick films are of real interest for devices such as ceramic Micro-ElectroMechanical Systems (MEMS) because they bridge the gap between thin films and bulk ceramics. The basic design of MEMS includes electrodes, a functional material, and a substrate, and efforts are currently [...] Read more.
Piezoelectric thick films are of real interest for devices such as ceramic Micro-ElectroMechanical Systems (MEMS) because they bridge the gap between thin films and bulk ceramics. The basic design of MEMS includes electrodes, a functional material, and a substrate, and efforts are currently focused on simplified processes. In this respect, screen-printing combined with a sacrificial layer approach is attractive due to its low cost and the wide range of targeted materials. Both the role and the nature of the sacrificial layer, usually a carbon or mineral type, depend on the process and the final device. First, a sacrificial layer method dedicated to screen-printed thick-film ceramic and LTCC MEMS is presented. Second, the recent processing of piezoelectric thick-film ceramic MEMS using spark plasma sintering combined with a protective layer approach is introduced. Whatever the approach, the focus is on the interdependent effects of the microstructure, chemistry, and strain/stress, which need to be controlled to ensure reliable and performant properties of the multilayer electroceramics. Here the goal is to highlight the benefits and the large perspectives of using sacrificial/protective layers, with an emphasis on the pros and cons of such a strategy when targeting a complex piezoelectric MEMS design. Full article
(This article belongs to the Special Issue Innovative Processing Routes for Electroactive Materials)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Synthesis and Pressure-assisted Sintering of CaCu3Ti4O12 Dielectrics
Authors: Jan PETRÁŠEK, Pavel CTIBOR and Josef SEDLÁČEK
Abstract: In this paper we examine dielectric properties of CaCu3Ti4O12 fired by spark plasma sintering (SPS) and attempt to discuss the most important conditions affecting its dielectric behavior. At first, we give a quick description of its structure and synthesis. In the experimental part we describe a molten salt-based synthesis route of the feedstock powder that showed however contradictory results. Annealing of the SPS bulk samples was carried out in air in a laboratory furnace using various regimes. Next and most promising samples were obtained by high-pressure applied before conventional sintering. At the dielectric measurements the electric field was applied along the pressure direction (i.e., perpendicular to the substrate face). The relative permittivity was calculated from measured capacitances for a wide frequency window and the loss tangent was measured simultaneously. Phase composition and lattice parameters were evaluated by means of X-ray diffraction (XRD). Porosity of the coatings was measured by image analysis of cross-sectional micrographs. Finally, we compared our results with some remarkable achievements found in literature. We are drawing several relations between the processing, microstructure and electrical properties. The results show that sintering temperature just below or equal to 1000 °C should be set at SPS process. Longer dwell time at the maximum temperature is more efficient for receiving defect-free compacts than high sintering temperature.

Title:Recent progress on the synthesis, characteristics, and tribology of electroactive polymers
Authors: Md Hafizur Rahman*, Ashish Kasar, Harmony Werth, Alexander Goldman, Court Diesnerale, Yuki Hida, Logan Lane, Pradeep L. Menezes
Abstract: Electroactive polymers (EAPs) are an advanced family of polymers that change their shape through electric stimulation and have been a point of interest since inception. This unique functionality has helped EAPs to contribute in versatile fields, such as electrical, biomedical, robotics, to name a few. The synthesis of the EAPs follows different routes based on available resources. Ionic EAPs have a significant advantage over electronic EAPs. For example, Ionic EAPs require a lower voltage to activate than electronic EAPs. On the other hand, electronic EAPs could generate a relatively larger actuation force. Therefore efforts have been focused to improve both kinds to achieve superior properties.  In this research, the synthesis routes of different EAPs would be investigated and summarized, and their properties would be discussed based on the literature. Moreover, their mechanical interactions will be investigated from a tribological perspective as all these EAPs interact with some surfaces. Such interactions could reduce their useful life and need significant research attention to getting improved. The current study would help the researchers learn about the tribological behavior of recently developed EAPs to achieve their increased utilization life. The underlying mechanisms and applications of these EAPs in various sectors are discussed.

Titile: Piezoelectrets for smart self-sensing and structural health monitoring of composite materials
Authors: Relebohile George Qhobosheane, Monjur Morshed Rabby, Vamsee Vadlamudi, Kenneth Reifsnider, Rassel Raihan
Abstract: The use of fiber-reinforced composite materials has widely spread in various sectors, including aerospace, defense, civil industry, etc. The assessment of these heterogeneous material systems is important for safer and risk-free applications and has contributed to the need for self-sensing composites. This work is focused on the development of piezoelectrets for the performance prediction and structural health monitoring (SHM) of smart self-sensing composites. Additionally, this work unpacks the complexity of carbon nanotubes (CNTs) micro-fabrication and the development of piezoelectric and electromagnetic (EM) waves detection electrodes. A nickel (Ni) film was used as catalyst for growing single-walled (SWCNTs) and multi-walled (MWCNTs) carbon nanotubes. Scanning electron microscopy (SEM) was used to characterize the CNTs structure and morphologies. The manufactured CNTs were incorporated in epoxy systems to fabricate glass fiber reinforced polymer (GFRP)-CNTs smart composites with piezoelectric properties. The detection of micro-damage onset and its progression was carried out in mode I and mode II, to evaluate the sensitivity of the smart composites to damage development. The change in electrical conductivity of the nanotubes-reinforced composite material systems due to localized mechanical strains enabled crack propagation detection. The relationship between crack propagation, fracture toughness, and piezoelectric response of the smart composite was analyzed.

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