This work was supported by the Taiyuan University of Science and Technology Scientific Research Initial Funding (20182028), the doctoral starting foundation of Shanxi Province (20192006), the Natural Science Foundation of Shanxi Province (201703D111003), the Science and Technology Major Project of Shanxi Province (MC2016-01), and Project U610256 supported by National Natural Science Foundation of China.

1. Surface modification of BT fillers
<ol>
	<li>Prepare 20 mL of KH550 solution (1 wt% KH550 in 95 wt% ethanol-water solvent) and ultrasonicate for 15 min.</li>
	<li>Weigh BT nanoparticles (i.e., the filler) and KH550, respectively, so that fillers can be coated with 1, 2, 3, 4, 5 wt% of the coupling agent. Treat 1 g of BT nanoparticles in 1.057, 2.114, 3.171, 4.228, and 5.285 mL of KH550 solution by 30 min ultrasonication.</li>
	<li>Evaporate the water-ethanol solvent from the mixture at 80 &#176;C for 5 h and then at 120 &#176;C for 12 h in a vacuum oven.</li>
	<li>Use the dry BT nanoparticles as the surface modified fillers to prepare BT-VC91 nanocomposites.</li>
</ol>
2. Preparation of BT-VC91 nanocomposites
<ol>
	<li>Dissolve 0.3 g of VC91 powders in 10 mL of N,N-dimethylformamide (DMF) at room temperature by magnetic stirring for 8 h to obtain a homogeneous VC91-DMF solution.</li>
	<li>Add 0.0542, 0.1145, 0.1819, 0.2578, 0.3437, and 0.4419 g of BT nanoparticles into 10 mL of VC91-DMF solution to obtain a final BT percentage of 5, 10, 15, 20, 25, and 30 vol% in the nanocomposites. Mix BT nanoparticles by magnetic stirring for 12 h and ultrasonication for 30 min to form a homogeneous BT-VC91-DMF suspension. 
	NOTE: Both the unmodified BT and BT nanoparticles coated with the coupling agent are used.</li>
	<li>Cast the suspension by evenly pouring the BT-VC91-DMF onto a preheated 75 mm x 25 mm glass substrate (3 mL per substrate). Keep the glass substrates with suspensions in the oven at 70 &#176;C for 8 h to evaporate the DMF solvent to form composite films.</li>
	<li>Release the composites from glass substrates using sharp tweezers to obtain free-standing BT-VC91 films. Anneal the films on a preheated dust-free paper at 160 &#176;C in air for 12 h.</li>
</ol>
3. Characterization and measurement
<ol>
	<li>Characterize the morphology and uniformity of nanocomposites using a scanning electron microscope (SEM). To do this, freeze BT-VC91 samples in liquid nitrogen and break to show fresh cross section with an approximate size of 5 mm x 30 &#181;m (i.e., the ceramic-polymer interface). Then coat one side of the cross section with a gold layer with a thickness of 3&#8722;5 nm and characterize the composite structure using an SEM (Table of Materials).</li>
	<li>Using a gold coater (Table of Materials), sputter gold layers with a positive circle shape, a diameter of 3 mm, and a thickness of ~50 nm on both sides of the nanocomposite prepared from step 2 to form the electrode for impedance testing.</li>
	<li>Characterize the capacitance and dielectric loss of the nanocomposites over a frequency range from 100 Hz to 1 MHz using an impedance analyzer (Table of Materials) with the Cp-D function. In the testing, connect gold layers on both sides of the composite film with the two poles of fixture.</li>
	<li>Calculate the dielectric constant (&#949;r) of nanocomposites from the capacitance obtained by impedance analyzer using the parallel capacitor model: 
	 
	&#949;r = dCp/&#949;0A 
	 
	where &#949;0 = 8.85 x 10-12, A is the area of gold electrodes, d is the thickness of sample, and Cp is parallel capacitance obtained by connecting the gold electrodes with the fixture of impedance analyzer.</li>
	<li>Characterize the breakdown strength of nanocomposites using a 10 kV high voltage supplier (Table of Materials). Increase the applied electric field evenly and continuously until the breakdown of each sample.</li>
	<li>Characterize the polarization-electric (P-E) field hysteresis loop of nanocomposites using a ferroelectric tester. Record the P-E loops at each electric field while continuously increasing the electric field.</li>
</ol>

<ol>
	<li>Lines, M. E., Glass, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Principles and applications of ferroelectrics and related materials. , (2001).</li><li>Nalwa, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of low and high dielectric permittivity materials and their applications, phenomena, properties and applications. , (1999).</li><li>Kao, K. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Dielectric phenomena in solids. , (2004).</li><li>Tong, Y., Li, L., Liu, J., Zhang, K., Jiang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+coupling+agent+on+the+microstructure+and+dielectric+properties+of+free-standing+ceramic-polymer+composites.">Influence of coupling agent on the microstructure and dielectric properties of free-standing ceramic-polymer composites.</a> Materials Research Express. 6 (9), 095322 (2019).</li><li>Zhang, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+functionalization+of+poly(4-methyl-1-pentene)+films+for+high+energy+storage+applications.">Controlled functionalization of poly(4-methyl-1-pentene) films for high energy storage applications.</a> Journal of Materials Chemistry A. 4 (13), 4797-4807 (2016).</li><li>Zhang, L., Cheng, Z. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+polymer-based+0-3+composites+with+high+dielectric+constant.">Development of polymer-based 0-3 composites with high dielectric constant.</a> Journal of Advanced Dielectrics. 1 (04), 389-406 (2011).</li><li>Barsoum, M., Barsoum, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fundamentals of ceramics. , (2002).</li><li>Jaffe, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Piezoelectric ceramics. , (2012).</li><li>Zhang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=All-organic+dielectric+nanocomposites+using+conducting+polypyrrole+nanoclips+as+filler.">All-organic dielectric nanocomposites using conducting polypyrrole nanoclips as filler.</a> Composites Science Technology. 167, 285-293 (2018).</li><li>Liao, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+hdC-G+reinforced+polyimide+composites+with+high+dielectric+permittivity.">Flexible hdC-G reinforced polyimide composites with high dielectric permittivity.</a> Composites Part A: Applied Science and Manufacturing. 101, 50-58 (2017).</li><li>Xu, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+foldable+PANi@+CNTs/PU+dielectric+composites+toward+thin-film+capacitor+application.">Highly foldable PANi@ CNTs/PU dielectric composites toward thin-film capacitor application.</a> Materials Letters. 192, 25-28 (2017).</li><li>Zhang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nano-clip+based+composites+with+a+low+percolation+threshold+and+high+dielectric+constant.">Nano-clip based composites with a low percolation threshold and high dielectric constant.</a> Nano Energy. 26, 550-557 (2016).</li><li>Zhou, S., Zhou, G., Jiang, S., Fan, P., Hou, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+and+refractory+tantalum+carbide-carbon+electrospun+nanofibers+with+high+modulus+and+electric+conductivity.">Flexible and refractory tantalum carbide-carbon electrospun nanofibers with high modulus and electric conductivity.</a> Materials Letters. 200, 97-100 (2017).</li><li>Zhang, L., Du, W., Nautiyal, A., Liu, Z., Zhang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+progress+on+nanostructured+conducting+polymers+and+composites:+synthesis,+application+and+future+aspects.">Recent progress on nanostructured conducting polymers and composites: synthesis, application and future aspects.</a> Science China Materials. 61 (3), 303-352 (2018).</li><li>Xie, Y., Yu, Y., Feng, Y., Jiang, W., Zhang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+Stretchable+Nanocomposites+with+High+Energy+Density+and+Low+Loss+from+Cross-Linked+PVDF+Filled+with+Poly(dopamine)+Encapsulated+BaTiO3.">Fabrication of Stretchable Nanocomposites with High Energy Density and Low Loss from Cross-Linked PVDF Filled with Poly(dopamine) Encapsulated BaTiO3.</a> ACS Applied Materials &amp; Interfaces. 9 (3), 2995-3005 (2017).</li><li>Zhang, L., Wu, P., Li, Y., Cheng, Z. Y., Brewer, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+process+and+dielectric+properties+of+Ba0.5Sr0.5TiO3-P(VDF-CTFE)+nanocomposites.">Preparation process and dielectric properties of Ba0.5Sr0.5TiO3-P(VDF-CTFE) nanocomposites.</a> Composite Part B: Engineering. 56, 284-289 (2014).</li><li>Dang, Z. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fundamentals,+processes+and+applications+of+high-permittivity+polymer-matrix+composites.">Fundamentals, processes and applications of high-permittivity polymer-matrix composites.</a> Progress in Materials Science. 57 (4), 660-723 (2012).</li><li>Wu, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+coupling+agents+on+the+dielectric+properties+and+energy+storage+of+Ba0.5Sr0.5TiO3/P(VDF-CTFE)+nanocomposites.">Effect of coupling agents on the dielectric properties and energy storage of Ba0.5Sr0.5TiO3/P(VDF-CTFE) nanocomposites.</a> AIP Advances. 7 (7), 075210 (2017).</li><li>Zhang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Process+and+microstructure+to+achieve+ultra-high+dielectric+constant+in+ceramic-polymer+composites.">Process and microstructure to achieve ultra-high dielectric constant in ceramic-polymer composites.</a> Scientific Reports. 6, 35763 (2016).</li><li>Lu, X., Tong, Y., Cheng, Z. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+and+characterization+of+free-standing,+flexible+and+translucent+BaTiO3-P+(VDF-CTFE)+nanocomposite+films.">Fabrication and characterization of free-standing, flexible and translucent BaTiO3-P (VDF-CTFE) nanocomposite films.</a> Journal of Alloys and Compounds. 770, 327-334 (2019).</li><li>Goyal, R. K., Katkade, S. S., Mule, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dielectric,+mechanical+and+thermal+properties+of+polymer/BaTiO3+composites+for+embedded+capacitor.">Dielectric, mechanical and thermal properties of polymer/BaTiO3 composites for embedded capacitor.</a> Composites Part B: Engineering. 44 (1), 128-132 (2013).</li><li>Pan, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+discharge+and+highenergy+density+of+nanocomposite+capacitors+using+Ba0.6Sr0.4TiO3nanofibers.">Fast discharge and highenergy density of nanocomposite capacitors using Ba0.6Sr0.4TiO3nanofibers.</a> Ceramics International. 42 (13), 14667-14674 (2016).</li><li>Hu, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+dielectric+properties+of+poly(vinylidene+fluoride)/Ba0.6Sr0.4TiO3+composites.">Preparation and dielectric properties of poly(vinylidene fluoride)/Ba0.6Sr0.4TiO3 composites.</a> Journal of Alloys and Compounds. 619, 686-692 (2015).</li><li>Chen, Y., Chan, H. L. W., Choy, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanocrystalline+lead+titanate+and+lead+titanate/vinylidene+fluoride-trifluoroethylene+0-3+nanocomposites.">Nanocrystalline lead titanate and lead titanate/vinylidene fluoride-trifluoroethylene 0-3 nanocomposites.</a> Journal of the American Ceramic Society. 81 (5), 1231-1236 (1998).</li><li>Singh, P., Borkar, H., Singh, B. P., Singh, V. N., Kumar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ferroelectric+polymer-ceramic+composite+thick+films+for+energy+storage+applications.">Ferroelectric polymer-ceramic composite thick films for energy storage applications.</a> AIP advances. 4 (8), 087117 (2014).</li><li>Dang, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fundamentals,+processes+and+applications+of+high-permittivity+polymer-matrix+composites.">Fundamentals, processes and applications of high-permittivity polymer-matrix composites.</a> Progress in Materials Science. 57 (4), 660-723 (2012).</li><li>Arbatti, M., Shan, X. B., Cheng, Z. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ceramic-Polymer+Composites+with+High+Dielectric+Constant.">Ceramic-Polymer Composites with High Dielectric Constant.</a> Advanced Materials. 19 (10), 1369-1372 (2007).</li><li>Fan, B., Liu, Y., He, D., Bai, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Achieving+polydimethylsiloxane/carbon+nanotube+(PDMS/CNT)+composites+with+extremely+low+dielectric+loss+and+adjustable+dielectric+constant+by+sandwich+structure.">Achieving polydimethylsiloxane/carbon nanotube (PDMS/CNT) composites with extremely low dielectric loss and adjustable dielectric constant by sandwich structure.</a> Applied Physics Letters. 112 (5), 052902 (2018).</li><li>Liao, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+surface-modified+TiO2+nanorod+array/P(VDF-HFP)+dielectric+capacitor+with+ultra-high+energy+density+and+efficiency.">A surface-modified TiO2 nanorod array/P(VDF-HFP) dielectric capacitor with ultra-high energy density and efficiency.</a> Journal of Materials Chemistry C. 5 (48), 12777-12784 (2017).</li><li>Mittal, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Silanes and Other Coupling Agents. 3, (2004).</li><li>Zhang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superior+Energy+Storage+Performances+of+Polymer+Nanocomposites+via+Modification+of+Filler/Polymer+Interfaces.">Superior Energy Storage Performances of Polymer Nanocomposites via Modification of Filler/Polymer Interfaces.</a> Advanced Materials Interfaces. 5 (11), 1800096 (2018).</li><li>Yeh, J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+and+optical+properties+of+PMMA-titania+hybrid+materials+prepared+by+sol-gel+approach+with+HEMA+as+coupling+agent.">Thermal and optical properties of PMMA-titania hybrid materials prepared by sol-gel approach with HEMA as coupling agent.</a> Journal of Applied Polymer Science. 94 (1), 400-405 (2004).</li><li>Yang, C., Song, H. S., Liu, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+coupling+agents+on+the+dielectric+properties+of+CaCu3Ti4O12/PVDF+composites.">Effect of coupling agents on the dielectric properties of CaCu3Ti4O12/PVDF composites.</a> Composites Part B: Engineering. 50, 180-186 (2013).</li><li>Iijima, M., Sato, N., Lenggoro, I. W., Kamiya, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+Modification+of+BaTiO3+Particles+by+Silane+Coupling+Agents+in+Different+Solvents+and+Their+Effect+on+Dielectric+Properties+of+BaTiO3/Epoxy+Composites.">Surface Modification of BaTiO3 Particles by Silane Coupling Agents in Different Solvents and Their Effect on Dielectric Properties of BaTiO3/Epoxy Composites.</a> Colloids and Surfaces A: Physicochemical and Engineering Aspects. 352 (1-3), 88-93 (2009).</li><li>Zhang, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+Dielectric+Tunability+of+Ba0.6Sr0.4TiO3/Poly(vinylidene+fluoride)+Composites+via+Interface+Modification+by+Silane+Coupling.">Enhanced Dielectric Tunability of Ba0.6Sr0.4TiO3/Poly(vinylidene fluoride) Composites via Interface Modification by Silane Coupling.</a> Agent. Composites Science and Technology. 129, 93-100 (2016).</li><li>Dang, Z. M., Wang, H. Y., Xu, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+Silane+Coupling+Agent+on+Morphology+and+Dielectric+Property+in+BaTiO3/Polyvinylidene+fluoride+Composites.">Influence of Silane Coupling Agent on Morphology and Dielectric Property in BaTiO3/Polyvinylidene fluoride Composites.</a> Applied Physics Letters. 89 (11), 112902 (2006).</li><li>Tong, Y., Zhang, L., Bass, P., Rolin, T. D., Cheng, Z. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+silane+coupling+agent+on+microstructure+and+properties+of+CCTO-P(VDF-CTFE)+composites.">Influence of silane coupling agent on microstructure and properties of CCTO-P(VDF-CTFE) composites.</a> Journal of Advanced Dielectrics. 8 (02), 1850008 (2018).</li><li>Shan, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> High dielectric constant 0-3 ceramic-polymer composites. , (2009).</li></ol>

The authors have nothing to disclose.

As discussed above, the method developed by this work could successfully improve the energy-storage performance of ceramic-polymer nanocomposites. To optimize the effect of such method, it is critical to control the amount of coupling agent used in ceramic-surface modification. For ceramic nanoparticles with a diameter of ~200 nm, it was experimentally determined that 2 wt% of KH550 could lead to a maximal energy density. For other composite systems, this conclusion may be used approximately when the fillers with the dia...

The dielectrics applied in electrical energy storage devices are mainly characterized using two important parameters: the dielectric constant (&#949;r) and the breakdown strength (Eb)1,2,3. In general, organic materials such as polypropylene (PP) exhibit a high Eb (~102 MV/m) and a low &#949;r (mostly &#60;5)4,5,6 while inorganic materials, especially ferroelectrics such as BaTiO3, exhibit a high &#949;r (103-104) and a low Eb (~100 MV/m)6,7,8. In some applications, flexibility and the ability to withstand high mechanical impacts are also important for fabricating dielectric capacitors4. Therefore, it is important to develop methods for preparing polymer-based dielectric composites, especially for the development of low-cost methods to create high-performance 0-3 nanocomposites with high &#949;r and Eb9,10,11,12,13,14,15,16,17,18. For this purpose, preparation methods based on ferroelectric polymer matrices such as the polar polymer PVDF and its correlated copolymers are widely accepted due to their higher &#949;r (~10)4,19,20. In these nanocomposites, particles with high er, especially ferroelectric ceramics, have been widely used as fillers6,20,21,22,23,24,25.
When developing methods for manufacturing ceramic-polymer composites, there is a general concern that dielectric properties can be significantly influenced by the distribution of fillers26. The homogeneity of dielectric composites is not only determined by the preparation methods, but also by the wettability between the matrix and fillers27. It has been proven by many studies that the non-uniformity of ceramic-polymer composites can be eliminated by physical processes such as spin-coating28,29 and hot-pressing19,26. However, neither of these two processes change the surface connection between fillers and matrices; therefore, the composites prepared by these methods are still limited in improving &#949;r and Eb19,27. Additionally, from a manufacturing point of view, inconvenient processes are undesirable for many applications because they can lead to much more complex fabrication processes28,29. In this regard, a simple and effective method is needed.
Currently, the most effective method to improve the compatibility of ceramic-polymer nanocomposites is based on the treatment of ceramic nanoparticles, which modifies the surface chemistry between fillers and matrices30,31. Recent studies have shown that coupling agents can be easily coated on ceramic nanoparticles and effectively modify the wettability between fillers and matrices without affecting the casting process32,33,34,35,36. For surface modification, it is widely accepted that for each composite system, there is a suitable amount of coupling agent, which corresponds to a maximal increase in energy storage density37; excess coupling agent in composites may result in a decline in the performance of products36,37,38. For dielectric composites using nano-sized ceramic fillers, it is speculated that the effectiveness of coupling agent mainly depends on the surface area of fillers. However, the critical amount to be used in each nano-sized system is yet to be determined. In short, further research is required to use coupling agents to develop simple processes for manufacturing ceramic-polymer nanocomposites.
In this work, BaTiO3 (BT), the most widely studied ferroelectric material with high dielectric constant, was used as fillers, and the P(VDF-CTFE) 91/9 mol% copolymer (VC91) was used as the polymer matrix for the preparation of ceramic-polymer composites. To modify the surface of the BT nanofillers, the commercially available 3-aminopropyltriethoxysilane (KH550) was purchased and used as a coupling agent. The critical amount of the nanocomposite system was determined through a series of experiment. An easy, low-cost, and widely applicable method is demonstrated to improve the energy density of nano-sized composite systems.

<table border="0" cellpadding="0" cellspacing="0" style="width:827px;" width="826">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">3-Aminopropyltriethoxysilane (KH550)</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:161px;">440140</td>
			<td style="width:223px;">Liquid, Assay: 99%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">95 wt.% ethanol-water</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:161px;">459836</td>
			<td>Liquid, Assay: 99.5%</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:259px;">BaTiO3 nanoparticles</td>
			<td style="width:184px;">US Research Nanomaterials</td>
			<td style="width:161px;">US3830</td>
			<td>In a diameter of about 200 nm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Ferroelectric tester</td>
			<td style="width:184px;">Radiant</td>
			<td style="width:161px;">Precision-LC100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Glass substrates</td>
			<td style="width:184px;">Citoglas</td>
			<td style="width:161px;">16397</td>
			<td>75 x 25 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Gold coater</td>
			<td style="width:184px;">Pelco</td>
			<td style="width:161px;">SC-6</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">High voltage supplier</td>
			<td style="width:184px;">Trek</td>
			<td style="width:161px;">610D</td>
			<td>10 kV</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Impedance analyzer</td>
			<td style="width:184px;">Keysight</td>
			<td style="width:161px;">4294A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">N, N dimethylformamide</td>
			<td style="width:184px;">Fisher Scientific</td>
			<td style="width:161px;">GEN002007</td>
			<td>Liquid</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">P(VDF-CTFE) 91/9 mol.% copolymer</td>
			<td style="width:184px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Scanning Electron Microscopy (SEM)</td>
			<td style="width:184px;">JEOL</td>
			<td style="width:161px;">JSM-7000F</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Vacuum oven</td>
			<td style="width:184px;">Heefei Kejing Materials Technology Co, Ltd</td>
			<td style="width:161px;">DZF-6020</td>
			<td></td>
		</tr>
	</tbody>
</table>

application of a coupling agent to improve the dielectric properties of polymer-based nanocomposites

In this work, an easy, low-cost, and widely applicable method was developed to improve the compatibility between the ceramic fillers and the polymer matrix by adding 3-aminopropyltriethoxysilane (KH550) as a coupling agent during the fabrication process of BaTiO3-P(VDF-CTFE) nanocomposites through solution casting. Results show that the use of KH550 can modify the surface of ceramic nanofillers; therefore, good wettability on the ceramic-polymer interface was achieved, and the enhanced energy storage performances were obtained by a suitable amount of the coupling agent. This method can be used to prepare flexible composites, which is highly desirable for the production of high-performance film capacitors. If an excessive amount of coupling agent is used in the process, the non-attached coupling agent can participate in complex reactions, which leads to a decrease in dielectric constant and an increase in dielectric loss.

The free-standing nanocomposite films with different contents of fillers were successfully fabricated as described in the protocol, and were labeled as xBT-VC91, where x is the volume percentage of BT in the composites. The effect of KH550 (coupling agent) on the morphology and microstructure of these BT-VC91 films was studied by SEM and shown in Figure 1. The SEM images of 30BT-VC91 nanocomposites with 1 and 5 wt% coupling agent are shown in Figure 1a and <stro...

Watch this Scientific Journal Video about Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites at JoVE.com

Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites

Here, we demonstrate a simple and low-cost solution-casting process to improve the compatibility between the filler and the matrix of polymer-based nanocomposites using surface modified BaTiO3 fillers, which can effectively enhance the energy density of the composites.

In this work, an easy, low-cost, and widely applicable method was developed to improve the compatibility between the ceramic fillers and the polymer ...

application-coupling-agent-to-improve-dielectric-properties-polymer

Research

Education

JoVE Core

JoVE Journal

Physics

Engineering

Unit 1

Capacitance

SCIENTISTS IN ACTION

5.7K Views.  Taiyuan University of Science and Technology. Here, we demonstrate a simple and low-cost solution-casting process to improve the compatibility between the filler and the matrix of polymer-based nanocomposites using surface modified BaTiO3 fillers, which can effectively enhance the energy density of the composites.

Video: Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites

Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials

Recently, disordered photonic materials have been suggested as an alternative to periodic crystals for the formation of a complete photonic bandgap (PBG). In this article we will describe the methods for constructing and characterizing macroscopic disordered photonic structures using microwaves. The microwave regime offers the most convenient experimental sample size to build and test PBG media. Easily manipulated dielectric lattice components extend flexibility in building various 2D structures on top of pre-printed plastic templates. Once built, the structures could be quickly modified with point and line defects to make freeform waveguides and filters. Testing is done using a widely available Vector Network Analyzer and pairs of microwave horn antennas. Due to the scale invariance property of electromagnetic fields, the results we obtained in the microwave region can be directly applied to infrared and optical regions. Our approach is simple but delivers exciting new insight into the nature of light and disordered matter interaction.

Our representative results include the first experimental demonstration of the existence of a complete and isotropic PBG in a two-dimensional (2D) hyperuniform disordered dielectric structure. Additionally we demonstrate experimentally the ability of this novel photonic structure to guide electromagnetic waves (EM) through freeform waveguides of arbitrary shape.

Disordered structures offer new mechanisms for forming photonic bandgaps and unprecedented freedom in functional-defect designs. To circumvent the computational challenges of disordered systems, we construct modular macroscopic samples of the new class of PBG materials and use microwaves to characterize their scale-invariant photonic properties, in an easy and inexpensive manner.

Recently, disordered photonic materials have been suggested as an alternative to periodic crystals for the formation of a complete photonic bandgap (PBG). ...

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and polar dielectric liquids. These bridges are unique from capillary bridges in that they exhibit extensibility beyond a few millimeters, have complex bi-directional mass transfer patterns, and emit non-Planck infrared radiation. A number of common solvents can form such bridges as well as low conductivity solutions and colloidal suspensions. The macroscopic behavior is governed by electrohydrodynamics and provides a means of studying fluid flow phenomena without the presence of rigid walls. Prior to the onset of a liquid bridge several important phenomena can be observed including advancing meniscus height (electrowetting), bulk fluid circulation (the Sumoto effect), and the ejection of charged droplets (electrospray). The interaction between surface, polarization, and displacement forces can be directly examined by varying applied voltage and bridge length. The electric field, assisted by gravity, stabilizes the liquid bridge against Rayleigh-Plateau instabilities. Construction of basic apparatus for both vertical and horizontal orientation along with operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Horizontal and vertical electrohydrodynamic liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields and polar dielectric liquids. The construction of basic apparatus and operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and ...

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. The aggressive scaling of feature sizes, both on devices and interconnects, leads to serious challenges to ensure the required product reliability. Standard reliability tests and post-mortem failure analysis provide only limited information about the physics of failure mechanisms and degradation kinetics. Therefore it is necessary to develop new experimental approaches and procedures to study the TDDB failure mechanisms and degradation kinetics in particular. In this paper, an in situ experimental methodology in the transmission electron microscope (TEM) is demonstrated to investigate the TDDB degradation and failure mechanisms in Cu/ULK interconnect stacks. High quality imaging and chemical analysis are used to study the kinetic process. The in situ electrical test is integrated into the TEM to provide an elevated electrical field to the dielectrics. Electron tomography is utilized to characterize the directed Cu diffusion in the insulating dielectrics. This experimental procedure opens a possibility to study the failure mechanism in interconnect stacks of microelectronic products, and it could also be extended to other structures in active devices.

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. This paper demonstrates the procedure of an in situ TDDB experiment in the transmission electron microscope, which opens a possibility to study the failure mechanism in microelectronic products.

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. ...

Fabrication Process of Silicone-based Dielectric Elastomer Actuators

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an elastomeric dielectric membrane sandwiched between two compliant electrodes. The large actuation strains of these transducers when used as actuators (over 300% area strain) and their soft and compliant nature has been exploited for a wide range of applications, including electrically tunable optics, haptic feedback devices, wave-energy harvesting, deformable cell-culture devices, compliant grippers, and propulsion of a bio-inspired fish-like airship. In most cases, DETs are made with a commercial proprietary acrylic elastomer and with hand-applied electrodes of carbon powder or carbon grease. This combination leads to non-reproducible and slow actuators exhibiting viscoelastic creep and a short lifetime. We present here a complete process flow for the reproducible fabrication of DETs based on thin elastomeric silicone films, including casting of thin silicone membranes, membrane release and prestretching, patterning of robust compliant electrodes, assembly and testing. The membranes are cast on flexible polyethylene terephthalate (PET) substrates coated with a water-soluble sacrificial layer for ease of release. The electrodes consist of carbon black particles dispersed into a silicone matrix and patterned using a stamping technique, which leads to precisely-defined compliant electrodes that present a high adhesion to the dielectric membrane on which they are applied.

This manuscript shows the fabrication process for the manufacture of dielectric elastomer soft actuators based on silicone membranes. The three key stages of production are presented in detail: blade casting of thin silicone membranes; pad printing of compliant electrodes; and the assembly of all the components.

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an ...

Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties

A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step process that finishes with Negishi coupling. Negishi coupling is a cross-coupling process in which a chemical precursor is first lithiated, followed by transmetallation with ZnCl2. The resultant organozinc compound can be coupled to a dibrominated aromatic precursor to give the conjugated monomer. Polymer films can be prepared via electropolymerization of the monomer and characterized using cyclic voltammetry and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. Nanoparticles (NPs) are prepared via emulsion polymerization of the monomer using a two-surfactant system to yield an aqueous dispersion of the polymer NPs. The NPs are characterized using dynamic light scattering, electron microscopy, and UV-Vis-NIR-spectroscopy. Cytocompatibility of NPs is investigated using the cell viability assay. Finally, the NP suspensions are irradiated with a NIR laser to determine their effectiveness as potential materials for photothermal therapy (PTT).

A protocol is presented for the synthesis and preparation of nanoparticles consisting of electroactive polymers.

A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

New Application of an Atmospheric Pressure Plasma Jet as a Neuro-protective Agent Against Glucose Deprivation-induced Injury of SH-SY5Y Cells

The atmospheric pressure plasma jet (APPJ) has attracted the attention of many researchers from multiple disciplines in recent years because its emissions include multiple types of reactive nitrogen species (RNS) and reactive oxygen species (ROS). Our previous study has shown the cytoprotective effect of the APPJ against oxidative stress-induced injuries. The aim of the present study is to provide a detailed in vitro treatment protocol regarding the neuroprotective applications of helium APPJs on glucose deprivation-induced injury in SH-SY5Y cells. The SH-SY5Y human neuroblastoma-derived cell line was maintained in RPMI 1640 medium supplemented with 15% fetal calf serum. The culture medium was then changed to RPMI 1640 without glucose before APPJ treatment. After a 1 h incubation in a cell incubator, cell viability was determined using Cell Counting Kit 8. The results showed that, compared to the glucose deprivation group, cells treated with APPJ exhibited significantly increased cell viability in a dose-dependent manner, with 8 s/well observed as an optimal dose. Meanwhile, helium flow had no effect on the glucose deprivation-induced cell impairment. Our results indicated that APPJ could be potentially used as a treatment method for the diseases in the central nervous system related to glucose deprivation. This protocol could also be used as a cytoprotective application for other cells with different impairments, but the cell culture and APPJ treatment conditions should be readjusted, and the treatment dose must be relatively low.

A protocol for the neuroprotective application of low-dose atmospheric pressure plasma treatment on glucose deprivation-induced SH-SY5Y injuries.

The atmospheric pressure plasma jet (APPJ) has attracted the attention of many researchers from multiple disciplines in recent years because its emissions ...

Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising from metallic periodic arrays without involving time-resolved techniques. We have formulated the rates by quantities that can be measured by simple optical measurements. The instrumentation based on angle- and polarization-resolved reflectivity and photoluminescence spectroscopy will be described in detail here. Our approach is intriguing due to its simplicity, which requires routine optics and several mechanical stages, and thus is highly affordable to most of the research laboratories.

This protocol describes the instrumentation for determining the excitation and coupling rates between light emitters and Bloch-like surface plasmon polaritons arising from periodic arrays.

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising ...

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on high-density data storage and low-power consumption capabilities. However, the high-quality oxide based nonvolatile memory on flexible substrates is often constrained by the material characteristics and the inevitable high-temperature fabrication process. In this paper, a protocol is proposed to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica. The versatile deposition technique and measurement method enable the fabrication of flexible yet single-crystalline non-volatile memory elements necessary for the next generation of smart devices.

In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on ...

Demonstration of Equal-Intensity Beam Generation by Dielectric Metasurfaces

The fabrication and characterization protocol for a metasurface beam splitter, enabling equal-intensity beam generation, is demonstrated. Hydrogenated amorphous silicon (a-Si:H) is deposited on the fused silica substrate, using plasma-enhanced chemical vapor deposition (PECVD). Typical amorphous silicon deposited by evaporation causes severe optical loss, impinging the operation at visible frequencies. Hydrogen atoms inside the amorphous silicon thin film can reduce the structural defects, improving optical loss. Nanostructures of a few hundreds of nanometers are required for the operation of metasurfaces in the visible frequencies. Conventional photolithography or direct laser writing is not feasible when fabricating such small structures, due to the diffraction limit. Hence, electron beam lithography (EBL) is utilized to define a chromium (Cr) mask on the thin film. During this process, the exposed resist is developed at a cold temperature to slow down the chemical reaction and make the pattern edges sharper. Finally, a-Si:H is etched along the mask, using inductively coupled plasma&#8211;reactive ion etching (ICP-RIE). The demonstrated method is not feasible for large-scale fabrication due to the low throughput of EBL, but it can be improved upon by combining it with nanoimprint lithography. The fabricated device is characterized by a customized optical setup consisting of a laser, polarizer, lens, power meter, and charge-coupled device (CCD). By changing the laser wavelength and polarization, the diffraction properties are measured. The measured diffracted beam powers are always equal, regardless of the incident polarization, as well as wavelength.

A protocol for the fabrication and optical characterization of dielectric metasurfaces is presented. This method can be applied to the fabrication of not only beam splitters, but also of general dielectric metasurfaces, such as lenses, holograms, and optical cloaks.

The fabrication and characterization protocol for a metasurface beam splitter, enabling equal-intensity beam generation, is demonstrated. Hydrogenated ...