Preparation of nanoplates assembled 4CaO·5B2O3·7H2O oval-like microspheres via a hydrothermal method

4CaO·5B2O3·7H2O uniform oval-like microspheres morphology has been prepared at 120 °C by a simple hydrothermal method with the help of the surfactant polyethylene glycol(PEG-300). The result indicates that 4CaO·5B2O3·7H2O oval-like microspheres are constructed by ladder-like layers, and each layer is made up of numerous densely packed nanoplates with the thickness of 50–100 nm and the diameter of several microns. The nanoplates in each layer are interconnected with the nanoplates in next layer, which leads to form the multilayered structural oval-like microspheres. The PEG-300 plays an important role in the formation of this oval-like microspheres morphology.