Polymer-based hollow microspheres: Preparation methods and applications

Due to their advantageous properties such as lower density, high specific surface and high loading capacity, polymer-based hollow microspheres show promising potential of applications in the areas of white pigment, carriers for drugs, bioactive and catalytically active substances, micro-reactor, etc. Thus, it is a worthwhile and challenging work to prepare polymer-based hollow microspheres by exploring new methods and new technologies. Here, the development of the preparation methods and applications of polymer-based hollow microspheres are reviewed. Firstly, the traditional methods, such as osmotic swelling method, hard template synthesis method, layer-by-layer assembly, and etc. are introduced. Then, the new methods presented in recent years, including self-assembly method, soft template synthesis method, Pickering emulsion polymerization and self-removing template method, are emphatically described. Furthermore, the applications of polymer-based hollow microspheres are introduced briefly. At last, the current problems as well as the corresponding research directions are discussed.