Understanding Surfaces and Interfaces in Nanocomposites of Silicone and Barium Titanate through Experiments and Modeling

Computational and experimental studies into particle surfaces and particle-matrix interfaces in nanocomposites of silicone and barium titanate (BTO) nanoparticles will be the focus of this presentation. BTO is a ferroelectric perovskite that is used in electronic devices and energy storage systems because of its high dielectric constant (up to 7,000). Research has shown that the dielectric constant of BTO drastically increases to 15,000 at a BTO particle diameter of 70 nm, which is an intriguing but highly contested result. Dielectric constants of BTO nanoparticles have been determined by fabricating, characterizing, and modeling surface-functionalized BTO powders incorporated into polymer matrices. These studies have indicated that BTO particle size does impact the dielectric constant of the perovskite. However, more sophisticated modeling and advanced characterization techniques are needed to better understand the nature and complexity of interfaces formed between polymers and BTO, as well as investigate the relationships between interfacial properties, nanocomposite properties, and nanoparticle properties.<br/><br/>Here we present experimental and theoretical research into the preparation, transmission electron microscope (TEM) characterization, and simulation of elastomer-matrix nanocomposites containing BTO nanoparticles with diameters ranging from 50 nm to 500 nm. Methods of functionalizing the surfaces of BTO nanoparticles, preparing nanocomposites of BTO and silicone, and determining the dielectric properties of BTO-silicone nanocomposites will be shown. TEM images of BTO nanoparticles in silicone will provide insight into interface formation and be related to (1) nanocomposite properties, (2) COMSOL models of the nanocomposites, and (3) density functional theory simulations of the interactions of water with BTO surfaces. The results from this project will advance our understanding of surfaces and interfaces in BTO-polymer nanocomposites, elucidate the particle size dependence of the BTO dielectric constant, and demonstrate an avenue toward manufacturing flexible elastomer-perovskite nanocomposites for wearable electronic devices and energy storage applications.<br/><br/>SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. This study was also supported by the National Science Foundation under Grant No. 1943599.