Microsphere Fabrication and Applications: an Overview

Abstract

The diversity of applications for spherical materials, often referred to as hollow or solid microspheres, microballoons, shells and microcapsules, span a wide range of technologies and attracts the talents of individuals from a broad set of disciplines. Consequently, this knowledge and capability is widely dispersed. A prime objective of this symposium was to bring that diverse community together to share, for mutual benefit, that knowledge and capability. This article highlights some of these diverse technologies and applications and identifies some of the many important literature sources encountered.

Carbon Nanotubes Encapsulated in Wormlike Hollow Silica Shells

“…The size of the spheres so produced, generally in the micrometer range, is limited by the nozzle technology. However, emulsion/phase separation procedures36 offer an opportunity to create spheres on the nanometer scale, where single and mixed ceramic oxides can be successfully processed 37–39. Yet another approach toward the production of hollow spheres comprises the use of sacrificial templates; the coating material is deposited via the controlled surface precipitation of inorganic molecular precursors from either solution or direct surface reactions,28, 40, 41 and the core can be subsequently removed either by heating (calcination) or by dissolution with a suitable solvent 26.…”

“…Excess PAH was removed by several centrifugation and redispersion cycles. The high density of positive charges on this polymer stems from a homogenous distribution of cationic groups (NH 3 + ) throughout its structure 36. Consequently, the polymer chains provide stable, individually dispersed carbon nanotubes with a uniform, positive outer surface, which facilitates the subsequent deposition of the first silica shell.…”

Synthesis of nanostructured metal oxide by liquid-phase deposition

“…Synthesizing micrometer-and nanometer-sized hollow ceramic particles has generated much interest, because they exhibit interesting properties [1][2][3]. These particles have great potential in the fields of electronics, photonics, optics, magnetics, and catalysis.…”

“…They can serve as small containers for encapusulating small chemical reactions and administering drugs. Several efforts have been made to synthesize hollow ceramic particles [1][2][3][4][5].…”

Fabrication of polymeric hollow spheres having macropores by a quenching and sublimation process

“…Recently, however, microporous materials based on organic polymers have been intensively studied as candidate materials for components of microelectronic devices. 11,12 Hollow microspheres [13][14][15][16][17][18] have generated particular interest because of their potential applications such as low-density capsules for controlled release of drugs, dyes, and inks, development of artificial cells, protection proteins, enzymes and DNA, as well as catalyst. Here we describe the preparation of polymeric hollow spheres with macropores.…”