Solution-phase colloidal synthesis

The approaches used for preparation of inorganic nanomaterials can be divided into two broad categories solution-phase colloidal synthesis and gas-phase synthesis. Metal and semiconductor nanoparticles are usually synthesized via solution-phase colloidal techniques,4,913 whereas high-temperature gas-phase processes like chemical vapor deposition (CVD), pulsed laser deposition (PLD), and vapor transfer are widely used for synthesis of high-quality semiconductor nanowires and carbon nanotubes.6,7 Such division reflects only the current research bias, as promising routes to metallic nanoparticles are also available based on vapor condensation14 and colloidal syntheses of high-quality semiconductor nanowires.15... 

Further detailed informadon on each of these methods is available in Ref. [29]. Solution-phase chemical syntheses are commonly used for the preparation of colloids of magnedc metal nanoparticles. Several general approaches can be used to control the size and shape of nanoparticles in solution-phase synthesis. 

In this section I will describe a small number of inorganic molecules from the large and diverse collection that have covalent bonds between their atoms. Molecules that have covalent bonds are used as precursors for synthesis of advanced solids either from the gas phase or from liquid solution using colloidal intermediates. 

Colloidal Biomolecules, Biomaterials, and Biomedical Applications, edited by Abdeihamid Eiaissari Gemini Surfactants Synthesis, Interfacial and Solution-Phase Behavior, and Applications, edited by Raoui Zana and Jiding Xia Colloidal Science of Flotation, Anh V. Nguyen and Hans Joachim Schuize... 

As an alternative to in situ growth, nanocrystals can be synthesized either in solution (e.g. by colloidal synthesis) or in the gas phase, prior to dispersion in a matrix or deposition or self-assembly onto a substrate. 

At the outset of the development of the synthesis of particles from solution there is an integrated approach which may be taken to optimize the production of particles with the desired features for a particular application. An understanding of how thermodynamic equilibrium is approached leads to an understanding of the phase stability of the desired solid phase. Fundamental principles of solution and colloid chemistry provide guidelines for control of particle size, particle shape and agglomeration. To complement the application of these fundamental principles, there are a number of computer programs that ease the trauma associated with predictions of phase stability, ionic equilibria, and predictions of agglomeration tendency. 

The role of reversed micelles in the manufacture of fine chemicals with enzymes also needs to be assessed and analysed. An outstanding example is lipase catalysed interesterification to produce cocoa butter substitute from readily available cheap materials (Luisi, 1985). This example of reversed micelles is sometimes referred to as a colloidal solution of water in organic systems. A number of water insoluble alkaloids, prostanoids, and steroids have been subjected to useful transformations (Martinek et al., 1987). Peptide synthesis has also been conducted. The advantages of two liquid phases are retained to a very great extent the amount of water can be manipulated to gain advantages from an equilibrium viewpoint. 

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