Environmental Engineering Reference
In-Depth Information
CHAPTER 2
Synthesis of Nanoparticles and One-Dimensional
Nanomaterials
Hosik Park and Heechul Choi
2.1 Introduction
Nanomaterials can be defined as materials that have an average phase or grain
size of less than 100 nm. Nanomaterials exhibit novel properties which can significantly
differ from those of bulk materials due to their unique physicochemical (i.e., size, shape)
and surface (i.e., reactivity, conductivity) properties (Seigel, 1993). Also, nanomaterials
themselves have different properties depending on how nanomaterials are synthesized
and how their atoms and molecules are ordered. For example, metal oxide nanoparticles
including semiconductor nanoparticles, which were synthesized using different methods
and under different experimental conditions (i.e., temperature, reaction time), have
different physicochemical and surface properties (Chan et al., 2002 , Jung et al., 2007).
Recently, numerous approaches based on the application of these properties have been
developed and applied to the synthesis of nanomaterials. This implies that inherent
properties pertaining to chemical reactivity or physical compaction play an essential role
in nanomaterials synthesis.
In this chapter, several common and unique techniques for nanoparticles and
one-dimensional nanomaterials synthesis will be introduced.
2.2
Nanoparticles
Primarily, synthesis techniques for nanoparticles can be divided into “top-down”
approaches and “bottom-up” approaches. Top-down approaches typically start with a
suitable bulk material and then break the bulk material into smaller pieces. Ball-milling
or attrition and pattern formation are common methods of a top-down approach. For
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