Hollow particles as controlled small space to functionalize materials

Abstract

Molecules indicate a particular property by obeying a special characteristic in small space in some cases. It was discovered for a liquid phase such as decreasing the melting point in a nano-sized pore. A special phenomenon may also occur in the gas phase in a small space. To demonstrate this prediction, I have begun trying to fabricate a small space. A nano-sized hollow structure is very attractive for obtaining a small space. An inorganic template using inorganic particles is a facile technique to obtain hollow particles with various shapes, sizes, from nano to micron, and also different shell microstructures. This paper describes the solgel synthesis that is useful to form the shell structure of hollow particles and then how to control the particle structure using various templating routes. The hollow particles are used for the fabrication of air/solid composites with a controlled small space. These structure controls provide wide applications such as superior thermal insulation films, anti-corrosion films, and unexpected "easy-to-grip" volleyball coatings, etc. In addition to our achievements using hollow silica nanoparticles, the development of applications such as the lithium ion battery, biomedical products, catalysts, etc., will be outlined.

Bio‐Inspired Synthesis of Hollow Mesoporous Bioactive Glass Nanoparticles Using Calcium Carbonate as Solid Template

“…Stober's synthesis mechanism has been reported earlier for hollow silica nanoparticles with CaCO 3 as solid template with slight modifications [21,35,36] . TEOS is used as a traditional precursor of silica or bioactive glass based on its ability to readily undergo hydrolysis in aquatic conditions [37] . However the rate of hydrolysis for TEOS is much slower than other metal alkoxides thus requiring the presence of acid or base catalyst [37] …”

“…TEOS is used as a traditional precursor of silica or bioactive glass based on its ability to readily undergo hydrolysis in aquatic conditions [37] . However the rate of hydrolysis for TEOS is much slower than other metal alkoxides thus requiring the presence of acid or base catalyst [37] …”

Transformation of Stöber Silica Spheres to Hollow Nanocatalysts

“…For example, they not only can serve as nanocatalysts, but as medicine carriers, nanoreactors, adsorbents, and so forth. It is already a well‐established fact that by downsizing hollow spaces from micro‐to‐nano size without composition changing, exceptional properties are come to see . In addition, crafting micro/meso/macropores into the shell wall of a hollow or highly porous structure also considerably enhances its sieving effect, and provides connecting routes between the inner and outer surfaces .…”

“…It is already a well‐established fact that by downsizing hollow spaces from micro‐to‐nano size without composition changing, exceptional properties are come to see . In addition, crafting micro/meso/macropores into the shell wall of a hollow or highly porous structure also considerably enhances its sieving effect, and provides connecting routes between the inner and outer surfaces . Furthermore, the hierarchical pores and voids among the shells and the complex interior may virtually afford a “maze‐like structure” between the entry and exit points, which prolongs the residence‐time of reactant stream inside the catalyst while assisting their smooth diffusion into the catalyst and thus accelerates the chemical reactions .…”

Hollow Mesoporous Functional Hybrid Materials: Fascinating Platforms for Advanced Applications

“…Among the characteristics of advanced mesoporous materials, control of the morphology and texture of the particles is important for specific applications that depend on the particle shape. Therefore, mesoporous materials with various morphologies, including thin films, monoliths, fibers, rope‐based shapes, polyhedron, dense spheres, and hollow shapes, have been synthesized …”