A Facile Multi-interface Transformation Approach to Monodisperse Multiple-Shelled Periodic Mesoporous Organosilica Hollow Spheres
journal contributionposted on 24.06.2015, 00:00 by Zhaogang Teng, Xiaodan Su, Yuanyi Zheng, Junjie Zhang, Ying Liu, Shouju Wang, Jiang Wu, Guotao Chen, Jiandong Wang, Dongyuan Zhao, Guangming Lu
The synthesis of well-defined and complex hollow structures via a simple method is still a major challenge. In this work, a facile and controllable “multi-interface transformation” approach for preparation of monodisperse multi-shelled periodic mesoporous organosilica (PMO) hollow spheres has been established by a one-step hydrothermal treatment of successively grown organosilica particles. The multi-shelled PMO hollow spheres have inorganic–organic hybrid frameworks, controllable number (1–4) of shells, high surface area (∼805 m2/g), accessible ordered mesochannels (∼3.2 nm), large pore volume (1.0 cm3/g), and uniform and tunable diameter (300–550 nm), chamber size (4–54 nm), and shell thickness (10–30 nm). In addition, various organic groups (alkyl, aromatic, and heteroelement fragments) are successfully incorporated into the multi-shelled PMO hollow spheres by successively adding different bridged organosilica precursors. Notably, the distribution of different kinds of organic groups in the multi-shelled PMO hollow spheres can be precisely controlled, showing great potential for future applications. We propose that the formation of the multi-shelled PMO hollow structures is ascribed to the creation of multiple highly cross-linked organosilica interfaces, providing a new and interesting fundamental principle for PMO materials. Due to their unique structure and frameworks, triple-shelled ethane-bridged PMO hollow spheres were successfully loaded with an anti-cancer drug doxorubicin and perfluoropentane gas, which present excellent effects in the killing of cancer cells and ultrasound imaging. It is expected that the multi-interface transformation strategy provides a simple, controllable, versatile, and template-free method for preparation of various multifunctional PMOs for different applications.