Conclusion
In this experiment, the sub-20 nm HSNs with the inner cavity diameter of 8 nm can be scaled up in RPB, and they show uniform particles size and excellent monodispersity. As the anti-reflection additive agent, they can be incorporated into optical polymer matrices to reduce the refractive index and improved transparency of polymer effectively. Most importantly, the haze of polymer is unchanged basically by adding HSNs, indicating that HSNs with ultrafine grain size are well-dispersed in polymer matrix. All in all, this work provides a simple and effective method to stably synthesize the ultrafine HSNs, which can promote the development of the technology for the large-scale preparation and industrial application of anti-reflection materials.