Silica/Cesium Tungsten Bronze Composite Nanospheres with Synergistically Enhanced Thermal Insulation Properties for Transparent Coatings

The development of functional thermal insulation materials is of great significance for energy saving and emission reduction in the building field and is meanwhile a powerful strategy for the construction of a low-carbon society. Cesium tungsten bronze nanomaterials (CWO) have attracted increasing attention in the field of transparent coating for their excellent near-infrared shielding performance, but their practical application is severely limited by the problems of particle agglomeration and secondary heat release. Here, silica hollow microspheres (HSNs) with an ultrathin pleated shell and adjustable particle size were prepared with multiblock polyurethane surfactants as a soft template. Silica/cesium tungsten bronze composites (CWO@HSNs) with synergistically enhanced thermal insulation properties were obtained via the surface modification of HSNs. CWO@HSN composite coatings with appropriate mass ratios of HSNs to CWO show significantly better optical properties and thermal insulation effects than those of CWO coating, with room temperature dropped by up to 11.5 °C and coating surface temperature reduced by 7.3 °C. Notably, the composite process of CWO with HSNs can not only inhibit the agglomeration of CWO but also greatly reduce the secondary heat release of the coatings, indicating an effective solution for improving the application performance of nanoscale cesium tungsten bronze in the field of building thermal insulation.