Tailoring the dielectric properties of silicone particles/poly(vinylidene fluoride) composites based on interface structures
-
摘要: 为降低硅粒子/聚偏氟乙烯(Si/PVDF)复合材料体系的介电损耗(tanδ)及提高其击穿强度(Eb),采用高温氧化及聚苯乙烯(PS)包覆法,制备出两种分别具有SiO2单壳及SiO2@PS双壳的Si@SiO2和Si@SiO2@PS核壳结构粒子。采用FTIR、XRD和TEM分析测试了核壳粒子的壳层结构。分析测试证明,Si粒子表面存在SiO2和PS壳层。结果表明,相比未改性Si/PVDF复合材料,SiO2外壳显著降低和抑制了Si@SiO2/PVDF复合材料的tanδ和漏导电流;PS层改进了Si/PVDF复合材料的界面相容性,促进其在基体中均匀分散。双壳结构Si@SiO2@PS/PVDF复合材料呈现出最低tanδ和最高Eb。Si@SiO2/PVDF和Si@SiO2@PS/PVDF复合材料介电性能的改善归因于Si表面SiO2及SiO2@PS绝缘界面层有效阻止了半导体Si粒子间的直接接触,极大抑制了损耗。此外,Si/PVDF复合材料相界面缺陷减少及界面相容性改善均有效降低了局部电场畸变,提高了体系的Eb。Si@SiO2@PS/PVDF复合材料在1 kHz下介电常数高达48,tanδ低至0.07,Eb约为6 kV/mm,在微电子器件及电力设备领域具有潜在的应用价值。Abstract: To reduce the dielectric loss(tanδ) and increase the dielectric breakdown strength(Eb) of silicon particles/poly(vinylidene fluoride)(Si/PVDF) composites, two kinds of core-shell structured Si particles, i.e., Si@SiO2 and Si@SiO2@PS were prepared by high temperature oxidation and polystyrene(PS) coating. The FTIR, XRD and TEM measurements were used to characterize the formed shell structure. The measurements results verify the existence of SiO2 and SiO2@PS shells on the surface of Si. The results show that the Si@SiO2 interlayer significantly suppresses the tanδ and reduces the leakage conductivity of the Si@SiO2/PVDF composites compared with Si/PVDF composites, and the double-shell Si@SiO2@PS/PVDF composites exhibit the lowest tanδ and the highest Eb among the three composites because the organic PS interlayer enhances the interfacial compatibility and promotes the fillers’ homogeneous dispersion in PVDF. The improvement in dielectric properties of Si@SiO2/PVDF and Si@SiO2@PS/PVDF composites can be ascribed to the facts that the insulating SiO2 and SiO2@PS shells effectively prevent the semi-conducting Si particles from direct contacting, thereby remarkably reducing the tanδ. The enhanced phase interfacial compatibility between the Si@SiO2 or Si@SiO2@PS and PVDF matrix reduces the interface defects and suppresses the local electrical field distortion, thereby improving Eb of the core-shell structured Si/PVDF composites. The prepared Si@SiO2@PS/PVDF composites with a high dielectric constant of 48 and tanδ of 0.07, Eb of 6 kV/mm, have potential applications in the field of microelectronic devices and power equipment.
-
Key words:
- Si /
- poly(vinylidene fluoride) /
- interface structure /
- core-shell structure /
- composites /
- dielectric properties
-
图 4 Si/PVDF、Si@SiO2/PVDF、Si@SiO2@PS/PVDF复合材料的介电性能(内图分别为Si/PVDF复合材料介电常数渗流理论计算及不同结构的核壳粒子结构示意图)
Figure 4. Dielectric properties of Si/PVD SiO2/PVDF and Si@SiO2@PS/PVDF composites(Insets in Fig. 4 show the theoretical calculation diagram of permittivity of Si/PVDF composites and the schematic diagram of core-shell particles with different structures)
-
[1] DANG Z M, ZHENG M S, ZHA J W. 1D/2D carbon nanomaterial-polymer dielectric composites with high permittivity for power energy storage applications[J]. Small,2016,12(13):1688-1701. doi: 10.1002/smll.201503193 [2] WANG Z, HAN N M, WU Y, et al. Ultrahigh dielectric constant and low loss of highly-aligned graphene aerogel/poly(vinyl alcohol) composites with insulating barriers[J]. Carbon,2017,123:385-394. doi: 10.1016/j.carbon.2017.07.079 [3] ZHOU W Y, KOU Y J, YUAN M X, et al. Polymer composites filled with core@double-shell structured fillers: Effects of multiple shells on dielectric and thermal properties[J]. Composites Science and Technology,2019,181:107686. doi: 10.1016/j.compscitech.2019.107686 [4] CHEN Y, ZHANG H B, YANG Y B, et al. High-performance epoxy nanocomposites reinforced with three-dimensional carbon nanotube sponge for electromagnetic interference shielding[J]. Advanced Functional Materials,2016,26(3):447-455. doi: 10.1002/adfm.201503782 [5] DANG Z M, WANG L, WANG H Y, et al. Rescaled temperature dependence of dielectric behavior of ferroelectric polymer composites[J]. Applied Physics Letters,2005,86(17):172905. [6] QI L, LEE B I, CHEN S, et al. High-dielectric-constant silver-epoxy composites as embedded dielectrics[J]. Advanced Materials,2005,17(14):1777-1781. doi: 10.1002/adma.200401816 [7] HE F, LAU S, CHAN H L, et al. High dielectric percolation threshold in nanocomposites based on poly(vinylidene fluoride) and exfoliated graphite nanoplates[J]. Advanced Materials,2009,21(6):710-715. doi: 10.1002/adma.200801758 [8] ZHAO Y H, LUO L, TANG H F, et al. Preparation of high-k composites with low dielectric loss based on the double-layer coaxial structure of inorganic/polymer[J]. Journal of Applied Polymer Science,2018,135(21):46299. doi: 10.1002/app.46299 [9] WANG L, DANG Z M. Carbon nanotube composites with high delectric constant at low percolation threshold[J]. Applied Physics Letters,2005,87(4):042903. doi: 10.1063/1.1996842 [10] WU Y, LIN X, SHEN X, et al. Exceptional dielectric properties of chlorine-doped graphene oxide/poly(vinylidene fluoride) nanocomposites[J]. Carbon,2015,89:102-112. doi: 10.1016/j.carbon.2015.02.074 [11] ZHOU W Y, GONG Y, TU L, et al. Dielectric properties and thermal conductivity of core-shell structured Ni@NiO/poly(vinylidene fluoride) composites[J]. Journal of Alloys <italic>&</italic> Compounds,2017,693:1-8. [12] WANG D, BAO Y, ZHA J W, et al. Improved dielectric properties of nanocomposites based on poly(vinylidene fluoride) and poly(vinyl alcohol)-functionalized graphene[J]. ACS Applied Materials <italic>&</italic> Interfaces,2012,4(11):6273-6279. doi: 10.1021/am3018652 [13] GONG Y, ZHOU W Y, WANG Z J, et al. Towards suppressing dielectric loss of GO/PVDF nanocomposites with TA-Fe coordination complexes as an interface layer[J]. Journal of Materials Science <italic>&</italic> Technology,2018,34(12):2415-2423. [14] LI Y, HUANG X, HU Z, et al. Large dielectric constant and high thermal conductivity in poly(vinylidene fluoride)/barium titanate/silicon carbide three-phase nanocomposites[J]. ACS Applied Materials <italic>&</italic> Interfaces,2011,3(11):4396-4403. [15] WEI H, WU Y, LUN N, et al. Preparation and photocatalysis of TiO<sub>2</sub> nanoparticles co-doped with nitrogen and lanthanum[J]. Journal of Materials Science,2004,39(4):1305-1308. doi: 10.1023/B:JMSC.0000013889.63705.f3 [16] XIE L, HUANG X, HUANG Y, et al. Core@double-shell structured BaTiO<sub>3</sub>-polymer nanocomposites with high dielectric constant and low dielectric loss for energy storage application[J]. Journal of Physical Chemistry C,2013,117(44):22525-22537. doi: 10.1021/jp407340n [17] XU X L, YANG C J, YANG J H, et al. Excellent dielectric properties of poly(vinylidene fluoride) composites based on partially reduced graphene oxide[J]. Composites Part B: Engineering,2017,109:91-100. doi: 10.1016/j.compositesb.2016.10.056 [18] LI Q, HAN K, GADINSKI M R, et al. High energy and power density capacitors from solution-processed ternary ferroelectric polymer nanocomposites[J]. Advanced Materials,2014,26(36):6244-6249. doi: 10.1002/adma.201402106 [19] THAKA T, KOZAKO M, FUSE N, et al. Proposal of a multi-core model for polymer nanocomposite dielectrics[J]. IEEE Transactions on Dielectrics and Electrical Insulation,2005,12(4):669-681. doi: 10.1109/TDEI.2005.1511092 [20] XU H P, DANG Z M, JIANG M J, et al. Enhanced dielectric properties and positive temperature coeffcient effect in the binary polymer composites with surface modified carbon black[J]. Journal of Materials Chemistry,2008,18(2):229-234. doi: 10.1039/B713857A [21] LIU L P, LV F Z, ZHANG Y H, et al. Enhanced dielectric performance of polyimide composites with modified sandwich-like SiO<sub>2</sub>@GO hybrids[J]. Composites Part A: Applied Science and Manufacturing,2017,99:41-47. doi: 10.1016/j.compositesa.2017.03.029 [22] DANG Z M, YUAN J K, ZHA J W, et al. Fundamentals, processes and applications of high-permittivity polymer-matrix composites[J]. Progress in Materials Science,2012,57(4):660-672. doi: 10.1016/j.pmatsci.2011.08.001