| Hollow micro/nanomaterials have been studied extensively for decades because of their growing number of applications in catalysis, separation, cosmetics, sorption, controlled release, energy storage, removal of pollutants and gas sensing. This research is aimed at the design of novel hollow materials with multilevel interior structures. Compared to traditional one and two-level structures, hollow micro/nanomaterials with multilevel interior structures are attractive because they not only have abundant and tunable inner voids and flexible chemical compositions, but also have large surface area and multiphase interfaces. However, there are not yet versatile methodologies to fabricate these complex structured materials because the synthesis is not easily controllable and often relies on the experiences of researchers. Additionally, the most commonly used template methods have a variety of obvious drawbacks, including tedious multistep procedure and cracking during template removal treatment, which greatly limit their large-scale production and applications.;To improve the synthetic methodologies for hollow materials with multilevel interior structures, three different unique structured hollow materials were developed successfully via a simple aerosol-based process in this study, i.e. double-shelled hollow microspheres, ultrasound responsive ultrathin-shelled hollow silica particles and multi-hole cage-like hollow structures. This research demonstrates that it is possible to fabricate double layer particles, with hydrophilic outer layer and hydrophobic layer, via an aerosol-based process. Control of the silica precursor levels leads to the generation of smart ultrathin-shelled particles which become susceptible to rupture upon exposure to external stimulus (ultrasound). Furthermore, using the aerosol-based process, new class of cage-like hollow material with multiple chambers and high surface areas has been fabricated.;In this thesis, the preparation and characterization of hollow materials with multilevel interior structures are presented in details. The hollow materials with multilevel interior structures developed in this study have the following beneficial characteristics: (1) abundant multilevel interior structures; (2) enhanced surface area; (3) multiphase interfaces; (4) environmentally benign preparation process; (5) the aerosol-based process is conducive to scale up. |
