Making hollows using nitrogen gas emitted by the decomposition of VAm-110 in polystyrene particles

Due to the useful features of hollow particles, such as the presence of nanovoids and their large specific surface areas, they have potential for use as drug carriers. Unfortunately, conventional methods for the synthesis of hollow particles involve complicated processes. In this study, we developed a template-free method for the production of hollow polymer particles. Polystyrene core particles containing 2,2′-azobis(N-butyl-2-methylpropionamide) (VAm-110) were initially formed via soap-free emulsion polymerization, after which shells were constructed using divinylbenzene. Nitrogen gas was then generated inside the particles by the decomposition of VAm-110 at 100 °C, which led to the formation of hollows. Consequently, this method involves three easy steps and is environmentally friendly, as it does not require the use of a surfactant or organic solvent. Furthermore, the morphology and size of the particle hollows can be controlled by varying the concentration of VAm-110. [Display omitted] •Hollow particles with monodispersed are synthesized without any templates.•Hollow structures were controllable by the temperature in the heating process.•The shell thickness of hollow particle was controllable by the concentration of divinylbenzene or VAm-110.