Monodispersed Colloidal Spheres: Old Materials with New Applications

Abstract

This article presents an overview of current research activities that center on monodispersed colloidal spheres whose diameter falls anywhere in the range of 10 nm to 1 mm. It is organized into three parts: The first part briefly discusses several useful methods that have been developed for producing monodispersed colloidal spheres with tightly controlled sizes and well-defined properties (both surface and bulk). The second part surveys some techniques that have been demonstrated for organizing these colloidal spheres into two-and three-dimensionally ordered lattices. The third part highlights a number of unique applications of these crystalline assemblies, such as their uses as photonic bandgap (PBG) crystals; as removable templates to fabricate macroporous materials with highly ordered and three-dimensionally interconnected porous structures; as physical masks in lithographic patterning; and as diffractive elements to fabricate new types of optical sensors. Finally, we conclude with some personal perspectives on the directions towards which future research in this area might be directed.

Three-Dimensional Photonic Crystals with Non-spherical Colloids as Building Blocks

“…[12] There are only a few methods (direct or indirect) available for generating non-spherical colloids with well-defined sizes and shapes. The direct methods produce non-spherical colloids from subunits such as molecular species by controlling the nucleation and growth steps.…”

Growth of Large Colloidal Crystals with Their (100) Planes Orientated Parallel to the Surfaces of Supporting Substrates

“…[3] These periodic structures have also been actively explored as functional components in fabricating new types of diffractive devices such as filters and switches, [4] smart optical sensors, [5] and photonic bandgap (PBG) structures. [6] As a matter of fact, recent studies on the unique optical properties of these materials have now evolved into a new, exciting field of research that is often referred to as photonic (bandgap) crystals. [7] …”

Cholesteric Liquid Crystals for Color Information Technology

“…It involves the application of photonic crystals [2] and cholesteric liquid crystals to information processing and display, respectively. Especially, a flat panel display in a reflection mode using a cholesteric liquid crystal has the advantages of saving electric power, memory property without electricity, and good visibility under high illumination.…”