Fabrication of Ag@BaTiO3 hybrid nanofibers via coaxial electrospinning toward polymeric composites with highly enhanced dielectric performances

doi:10.1016/j.coco.2020.100411

Composites Communications

Volume 21, October 2020, 100411

https://doi.org/10.1016/j.coco.2020.100411 Get rights and content

Highlights

•
Ag@BaTiO₃ hybrid nanofibers were successfully prepared by coaxial electrospinning followed by calcination.
•
Ag@BaTiO₃ hybrid nanofibers in PVDF matrix can improve dielectric constant.
•
Ag nanoparticles on BaTiO₃ nanofibers can induce low loss at 0.02@1 kHz.

Abstract

Here we demonstrated a remarkable improvement in the dielectric performance of poly (vinylidene fluoride) (PVDF)-based composites via incorporating distinguished hybrid nanofibers, namely, Ag nanoparticles-embedded BaTiO₃ (Ag@BaTiO₃, Ag@BT) nanofibers, which were fabricated by coaxial electrospinning technology followed by calcination. The Ag nanoparticles on BaTiO₃ nanofibers were found to play a comprehensive role on the dielectric performances, including the better dispersion of hybrid nanofibers leading to homogeneity of electric field, the formation of charge transfer complex in the hybrid region which enhanced the interfacial polarization, and the Coulomb blockade effect of Ag nanoparticles to further suppress the interfacial charge accumulation. As a result, the PVDF/Ag@BT composites exhibited high dielectric constant of 38.87@1 kHz and low loss of 0.02@1 kHz.

Introduction

Recently, Polymeric films such as Biaxially-oriented Polypropylene (BOPP), Polyethylene naphthalate (PEN), and Polyimide (PI) et al. have opened a scope of application in the field of dielectric capacitor [1], because the polymer can offer high breakdown strength, flexibility and easy processability. Generally speaking, the dielectric capacitor with high dielectric constant and low loss are highly desired to meet the requirement of electronic devices. To enhance the dielectric constant of polymer, a pretty high loading of ceramic particles (>30 vol %) were added into the polymer but at the cost of high dielectric loss [[2], [3], [4]]. Such phenomenon can be attributed to the enhanced interfacial polarization and serious distortion of electric field distribution at the interface of polymer/ceramic composites. On the other hand, aggregates of ceramic particles can be easily formed, deteriorating the processability and mechanical performance of composites. To overcome these problems, some strategies have been applied to enhance the dielectric performance in the polymer/ceramic composites, as follows: (i) Surface modification, including “grafting to” or “grafting from” method [[5], [6], [7]], polymer wrapping [8,9], and constructing “core-shell” hybrid fillers [[10], [11], [12]] etc, is the most common strategy, which can improve the dispersion of ceramic particles in matrix and minimize the interfacial defects. (ii) The second strategy is to decorate the semi-conductive/conductive nanoparticles on ceramic particles to prepare hybrid fillers, which can enhance interfacial polarization for high constant and induce Coulomb blockade effect for low loss [[13], [14], [15]]. However, surface modifications usually involve complex synthesis process; and regarding to the hybrid fillers, the nanoparticles exfoliation from ceramics may occur during processing. Therefore, exploring a new method to tailor the structure and property of dielectric filler is still a critical issue.

Based on the information mentioned above, we prepared a novel kind of Ag@BaTiO₃ (Ag@BT) nanofibers via coaxial electrospinning technology, and then they were added into the PVDF matrix to prepare the PVDF dielectric composites. The advantages for designing the structure of distinguished nanofiber can be listed as follows: (i) The one-dimensional fibers have large aspect ratio than zero-dimensional particles [[16], [17], [18]], exhibiting strong interfacial polarization. (ii) Ag nanoparticles on BaTiO₃ nanofibers may act as Coulomb islands, which are proposed to suppress the electron motion through the composites, and further suppress the dielectric loss. (iii) Such hybrid nanofibers are proposed to be achieved by simple coaxial electrospinning followed by calcination process, in which growth of Ag nanoparticles and BaTiO₃ nanofiber simultaneously occur. Thus, the Ag nanoparticles are supposed to be embedded into the surface of BaTiO₃ nanofibers, and the exfoliation of Ag nanoparticles from BaTiO₃ nanofibers during processing could be avoided. Based on the incorporation of Ag@BT nanofibers, the dielectric performance of polymer composites was investigated. The results show that the PVDF/Ag@BT composites exhibit enhanced dielectric constant and suppressed dielectric loss.

Section snippets

Materials

PVDF (droplets, Kynar 720) with a weight average molecular weight (M_w) of 1.05 × 10⁵ g/mol and a density of 1.78 g/cm³ was purchased from Arkema (France). Barium acetate ((CH₃COO)₂Ba), Butyl titanate (TBT), Acetylacetone, N, N-Dimethylformamide (DMF), acetic acid and ethanol with analytic grade (purity >99%) were purchased from Chengdu Kelong Chemical Co. Ltd and used without any treatment. Silver nitrate with analytic grade (purity >99%) and PVP with M_w = 1.3 × 10⁶ g/mol were purchased from

Synthesis and characterization of Ag@BT nanofibers

The precursor of Ag@BT nanofibers was preapred via coaxial electrospinning, and the achieved precursor was shown in the inset picture of Fig. 1(a). It can be found that the as-spun precursor nanofibers have smooth surfaces and continuous nanofiber features with diameter of 200–300 nm. The as-spun nanofibers were subjected to calcination at 600 °C for the pyrolysis of organic constituents. TGA curves in Fig. 1(a) were obtained to determine the pyrolysis processing for hybrid nanofibers. The

Conclusions

This work demonstrates that incorporating high-aspect-ratio Ag@BT hybrid nanofibers into PVDF is a novel and effective approach to achieve PVDF-based composites with high dielectric constant and low loss. The Ag@BT nanofibers are successfully fabricated by coaxial electrospinning followed by calcination, and the Ag nanoparticles show strong affinity with BaTiO₃ fibers. The Ag nanoparticles play a comprehensive role on tailoring dielectric properties toward high dielectric constant and low loss.

CRediT authorship contribution statement

Mao Wang: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing - original draft, Writing - review & editing. Xiao-ren Pan: Investigation, Visualization. Xiao-dong Qi: Investigation, Methodology. Nan Zhang: Investigation, Methodology. Ting Huang: Investigation, Methodology. Jing-hui Yang: Conceptualization, Investigation, Funding acquisition, Writing - review & editing. Yong Wang: Conceptualization, Investigation, Funding acquisition, Project administration,

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

. SEM image of BaTiO₃ nanofibers.

. TEM image and EDS mapping of Ag@BT nanofibers.

. UV spectra of PVDF, PVDF/BT and PVDF/Ag@BT composites. The content of Ag in the Ag@BT nanofibers is 0.7 wt%.

. Frequency dependence of conductivity of the (a) PVDF/Ag@BT and (b) PVDF/BT composites containing different contents of

Acknowledgment

This work was financially supported by the National Natural Science Foundation of China (51673159), the Key Research and Development Program of Sichuan Province (2017GZ0409), the International Science and Technology Cooperation Project of Chengdu (2016-GH02-00097-HZ), and the Fundamental Research Funds for the Central Universities (2682019JQ04). SEM and TEM characterizations were supported by the Analytical and Testing Center of Southwest Jiaotong University.

References (25)

N. Meng et al.
Crystallization kinetics and enhanced dielectric properties of free standing lead-free PVDF based composite films
Polymer
(2017)
Y.J. Wan et al.
Recent advances in polymer-based electronic packaging materials
Compos. Commun.
(2020)
Y.F. Ni et al.
Fabrication of natural rubber dielectric elastomers with enhanced thermal conductivity via dopamine chemistry
Compos. Commun.
(2019)
X. Xie et al.
Achieving high performance poly(vinylidene fluoride) dielectric composites via in situ polymerization of polypyrrole nanoparticles on hydroxylated BaTiO₃ particles
Chem. Sci.
(2019)
Y. Zhou et al.
Ehanced dielectric properties of poly(vinylidene fluoride-co-hexafluoropropylene) nanocomposites using oriented nickel nanowires
Compos. Commun.
(2019)
H. Li et al.
Preparation of heterostructured Ag/BaTiO₃ nanofibers via electrospinning
J. Alloys Compd.
(2010)
Q. Li et al.
High-temperature dielectric materials for electrical energy storage
Annu. Rev. Mater. Res.
(2018)
P. Kim et al.
High energy density nanocomposites based on surface-modified BaTiO₃ and a ferroelectric polymer
ACS Nano
(2009)
X. Pei et al.
Synergistic enhanced dielectric properties of PVDF nanocomposites containing γ-oxo-pyrenebutyric acid functionalized graphene and BaTiO₃ nanofiller
Compos. Commun.
(2019)
G.Y. Wang et al.
Bio-inspired fluoro-polydopamine meets barium titanate nanowires: a perfect combination to enhance energy storage capability of polymer nanocomposites
ACS Appl. Mater. Interfaces
(2017)

Y. Song et al.

Enhanced dielectric and ferroelectric properties induced by dopamine-modified BaTiO₃ nanofibers in flexible poly(vinylidene fluoride-trifluoroethylene) nanocomposites

J. Mater. Chem. A.

(2012)

D. Kang et al.

Decorating TiO₂ nanowires with BaTiO₃ nanoparticles: a new approach leading to substantially enhanced energy storage capability of high-k polymer nanocomposites

ACS Appl. Mater. Interfaces

(2018)

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Fabrication of Ag@BaTiO3 hybrid nanofibers via coaxial electrospinning toward polymeric composites with highly enhanced dielectric performances

Highlights

Abstract

Introduction

Section snippets

Materials

Synthesis and characterization of Ag@BT nanofibers

Conclusions

CRediT authorship contribution statement

Declaration of competing interest

Acknowledgment

Polymer

Compos. Commun.

Compos. Commun.

Chem. Sci.

Compos. Commun.

J. Alloys Compd.

High-temperature dielectric materials for electrical energy storage

Annu. Rev. Mater. Res.

High energy density nanocomposites based on surface-modified BaTiO3 and a ferroelectric polymer

ACS Nano

Synergistic enhanced dielectric properties of PVDF nanocomposites containing γ-oxo-pyrenebutyric acid functionalized graphene and BaTiO3 nanofiller

Compos. Commun.

Bio-inspired fluoro-polydopamine meets barium titanate nanowires: a perfect combination to enhance energy storage capability of polymer nanocomposites

ACS Appl. Mater. Interfaces

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Fabrication of Ag@BaTiO₃ hybrid nanofibers via coaxial electrospinning toward polymeric composites with highly enhanced dielectric performances

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Decorating TiO₂ nanowires with BaTiO₃ nanoparticles: a new approach leading to substantially enhanced energy storage capability of high-k polymer nanocomposites