Water-Mediated Conversion of BaTiO3 Nanoparticles into BaCO3 Nanorods in Electrospun Polymer Fibers: Implications for Carbon Capture Applications

Under ambient conditions and in aqueous environments, transformations of nanoparticle-based ferroelectric components can raise important stability issues that are relevant for applications as multilayer capacitors, flexible piezoelectrics, or biomedical devices. We show that X-ray amorphous BaTiO3 nanoparticles that were grown by flame spray pyrolysis and which can be incorporated into electrospun polymer fibers undergo incongruent Ba2+ dissolution in the presence of water. At pH > 5 and in contact with air, corresponding Ba solutes spontaneously convert into crystalline BaCO3 needles to produce characteristic nano- and microstructures. We compared the reactivity of amorphous BaTiO3 nanoparticle powders with those of nanocrystals after annealing-induced crystallization. The stability of aqueous nanoparticle-polymer formulations, which are typically part of nanoparticle encapsulation in polymers and electrospinning, was included in this analysis. Nanoparticle size, crystallinity, surface area, the presence of carbonaceous surface contaminants, and the effect of surface passivation with polymers are addressed to underline the critical role of condensed water during the synthesis, storage, and processing of BaTiO3 nanoparticle-based composites.

Automated summary

Transformations of nanoparticle-based ferroelectric components in aqueous environments raise stability issues that are important for various applications. This study investigates the dissolution and crystallization behavior of BaTiO3 nanoparticles in water and shows that the nanoparticles undergo incongruent Ba2+ dissolution, resulting in the formation of crystalline BaCO3 needles. The size, crystallinity, surface contaminants, and surface passivation with polymers are found to play critical roles in the stability of these nanoparticle-based composites.