Hierarchical Laminar Superstructures of Rhombic Priceite (Ca4B10O19 • 7H2O): Facile Hydrothermal Synthesis, Shape Evolution, Optical, and Thermal Decomposition Properties

The assembly of nanosheets/nanoplates into three-dimensional hierarchical superstructures brings unexpected properties and unique applications. However, to organize borate nanostructures into ordered superstructures is still a great challenge. Herein, uniform hierarchical laminar priceite (Ca4B10O19 center dot 7H(2)O) superstructures were synthesized via a facile hydrothermal route, in the absence of any templates, surfactants, or capping reagents. The as-prepared hierarchical laminar Ca4B10O19 center dot 7H(2)O superstructures containing rhombic nanosheets were formed by the dissolution-recrystallization controlled growth and subsequent hydrothermal self-assembly and could also be further disassembled into the rhombic nanosheets by hydrothermal treatment over time. The superstructures exhibited transmittance vibrational bands concentrating on the wavenumber range 1750-450 cm(-1), lost weight continuously within the temperature range 125-586 degrees C and kept constant weight thereafter, and demonstrated weak absorptions within the wavelength range 220-245 nm and 580-610 nm. The as-synthesized uniform hierarchical laminar Ca4B10O19 center dot 7H(2)O superstructures and nanosheets were expected as a sort of potential building blocks for advanced functional materials, as well as a flame retardant in polymer-based composites with a quasi transparent characteristic within the UV-vis region.