Effect of the fabrication method on the functional properties of BaTiO3: PVDF nanocomposites
TL;DR: In this article, the preparation and characterization of nanocomposite (NC) materials, comparing different technologies for sample fabrication, in view of their possible application as piezoelectric sensors, are investigated.
Abstract: This paper deals with the preparation and characterization of nanocomposite (NC) materials, comparing different technologies for sample fabrication, in view of their possible application as piezoelectric sensors. Those NCs consist on BaTiO3 nanoparticles embedded into a polyvinylidene fluoride matrix, where both the ceramic and the polymeric phases could exhibit ferroelectricity. In particular, we compare the properties of samples prepared through three different methods, i.e., solvent casting, enabling a fast realization, spin-coating, which allows to realize thin flexible films particularly interesting for large area sensors, and hot embossing, which is exploited to modify the residual porosity in the thick films. The influence of the fabrication techniques on the physical and chemical properties is investigated. Different electrode materials have been tested and compared, ranging from sputtered Pt to an engineered thermally evaporated Ti/Au bilayer. Leakage current, polarization, displacement curves, and piezoelectric coefficient d
33 are evaluated by small signal indirect measurements, comparing the properties of different materials and understanding how processing technologies influence the sensor performances by acting on the functional materials.
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TL;DR: In this paper, a fabrication process to enhance homogeneous dispersion of BaTiO3 nanoparticles in polyvinylidene fluoride matrix nanocomposites using fused deposition modeling (FDM) 3D printin...
Abstract: This paper presents a fabrication process to enhance homogeneous dispersion of BaTiO3 nanoparticles in polyvinylidene fluoride matrix nanocomposites using fused deposition modeling (FDM) 3D printin...
113 citations
Cites background or methods from "Effect of the fabrication method on..."
...BaTiO3 (BTO) is preferred as inorganic filler due to its environmentally friendly nature and ease in handling as lead-free material.(4) However, BTO has poor flexibility which limits applications for large scale fabrication....
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...A simple effective way to fabricate the nanocomposites is the solventcasting method.(4) However, this method has a disadvantage in heterogeneous dispersion and agglomeration of BTO nanoparticles within the PVDF matrix....
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TL;DR: The obtained results show the critical role of the bonding layer and piezoelectric layer thickness in the ME performance of laminate composites.
Abstract: The effect of the bonding layer type and piezoelectric layer thickness on the magnetoelectric (ME) response of layered poly(vinylidene fluoride) (PVDF)/epoxy/Vitrovac composites is reported. Three distinct epoxy types were tested, commercially known as M-Bond, Devcon, and Stycast. The main differences among them are their different mechanical characteristics, in particular the value of the Young modulus, and the coupling with the polymer and Vitrovac (Fe39Ni39Mo4Si6B12) layers of the laminate. The laminated composites prepared with M-Bond epoxy exhibit the highest ME coupling. Experimental results also show that the ME response increases with increasing PVDF thickness, the highest ME response of 53 V·cm–1·Oe–1 being obtained for a 110 μm thick PVDF/M-Bond epoxy/Vitrovac laminate. The behavior of the ME laminates with increasing temperatures up to 90 °C shows a decrease of more than 80% in the ME response of the laminate, explained by the deteriorated coupling between the different layers. A two-dimensiona...
78 citations
16 Oct 2017
TL;DR: In this paper, the β-content in polyvinylidene fluoride (PVDF) fibrous mat was found to increase by about 8% for Ag-NPs content of 0.4-0.6%.
Abstract: Poly(vinylidene fluoride) (PVDF) is a piezoelectric material with outstanding physical and mechanical properties. The piezoelectric properties depend on the β-phase content of this polymer, while the physical and mechanical properties depend on the morphology and degree of crystallinity of the material. Silver has antibacterial effects, and silver nanoparticles (Ag-NPs) have large surface areas rich in electrons. In this paper, we produced electrospun PVDF fibrous mats that contained different contents of Ag-NPs between 0% and 1.0%. The β-content in PVDF was found to increase by about 8% for Ag-NPs content of 0.4–0.6%. The electrospun fiber mats had a higher β-crystalline content, nano-pores were visible on the fiber surfaces, and the tensile strength and thermal stability were improved. Dielectric analysis indicated weak interfacial adhesion between the PVDF and Ag-NPs. Good piezoelectric response was observed in the electrospun fibers containing 0.4% AgNPs, which shows a good correlation between the β-crystalline phase content of the composites and its energy-harvesting application.
73 citations
Cites methods from "Effect of the fabrication method on..."
...Finally, ferroelectric materials such as barium titanate were used to enhance the β-phase content as the ceramic nanoparticles act as nucleating agent for the crystallization of the PVDF matrix [13]....
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TL;DR: In this paper, a review of the nanostructured polymers can be obtained and discuss reports on the ferroelectric and piezoelectric properties of the poly(vinylidene fluoride) and trifluoride-trifluoroethylene (TrFE) materials.
Abstract: Among the wide variety of piezoelectric materials available, polymers offer an interesting solution because of their high mechanical flexibility, easy processing, and conformable features; they maintain good ferroelectric and piezoelectric properties. The most prominent examples of these are poly(vinylidene fluoride) (PVDF) and its copolymer, poly(vinylidene difluoride–trifluoroethylene) [P(VDF–TrFE)]. An attractive prospective consists of the preparation of nanostructured polymers. It has been shown that the dimensional confinement of such macromolecules down to the nanoscale can improve their piezoelectric properties because the tailoring of the chemical structure is performed at the molecular level. In this review, we show how nanostructured polymers can be obtained and discuss reports on the ferroelectric and piezoelectric properties of nanostructured PVDF and P(VDF–TrFE) materials. In particular, we show how dimensional confinement leads to piezoelectric nanostructures with relevant performances, with a focus on the macromolecular structural arrangement that enhances their behavior. Experimental results and applications are also reported to compare the performances of different nanostructuration processes and the polymer efficiencies as piezoelectric materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41667.
56 citations
TL;DR: In this paper, the morphology and structure of solvent cast and compression-molded films, and their thermal, viscoelastic, and dielectric properties were investigated, and surface modified BaTiO3 particles were incorporated in poly(vinylidene fluoride-trifluoroethylene) to fabricate composites with up to 60 vol% of ceramic phase.
Abstract: Micron- and submicron-sized barium titanate (BaTiO3) particles, untreated and surface modified with aminopropyl triethoxy silane, were incorporated in poly(vinylidene fluoride–trifluoroethylene) to fabricate composites with up to 60 vol% of ceramic phase. The morphology and structure of solvent cast and compression-molded films, and their thermal, viscoelastic, and dielectric properties were investigated. When surface-modified BaTiO3 was used, it was possible to decrease both the viscoelastic and the dielectric losses of highly filled solvent cast films, while their storage modulus and relative permittivity either increased or remained equal, owing to reduced porosity and improved matrix-filler compatibility. The effect of BaTiO3 surface modification on the morphology of compression-molded films was less marked, leading to unchanged viscoelastic properties, and lower permittivity and dielectric losses. For all composites the frequency dependency of the dielectric properties at low frequencies was suppressed with modified BaTiO3.
54 citations
References
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TL;DR: In this article, a series and parallel model for composite piezoelectric and pyroelectrics is presented, which leads to several interesting results, such as a diphasic pyroelectric in which neither phase is pyrocharged.
1,706 citations
TL;DR: In this article, hot embossing is used as a flexible, low-cost microfabrication method for polymer microstructures, which uses the replication of a micromachined emplossing master to generate micro-structures on a polymer substrate.
Abstract: Polymer microfabrication methods are becoming increasingly important as low-cost alternatives to the silicon or glass-based MEMS technologies We present in this paper the technology of hot embossing as a flexible, low-cost microfabrication method for polymer microstructures, which uses the replication of a micromachined embossing master to generate microstructures on a polymer substrate With this fabrication technology high aspect ratio structures can be fabricated over large surface areas, which allows a commercially successful manufacturing of polymer microcomponents
686 citations
552 citations
TL;DR: This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5TiO 3, Na 0.5Bi0.4NbO3 and their solid solutions.
Abstract: Piezoelectrics have widespread use in today’s sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1-x] O3 (PZT),are comprised of more than 60 weight percent lead (Pb). Dueto its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided.
398 citations
TL;DR: In this article, the effect of solvent type and temperature on the formation of the α and β phases from solution cast PVDF was investigated, and it was shown that the type of phase formed depends on the crystallization rate of PVDF, which in turn is determined by the evaporation rate of the solvent.
259 citations