Nanoparticles surfactant/liquid crystalline phase

Using a y-irradiation technique, hexagonal PANI nanoparticles have been prepared in the hexagonal lyotropic liquid crystalline phases of a non-ionic and biodegradable surfactant alkyl polyglucoside (GP215 CS UP) in water and/or medium and long chain alkanes, used as a template [421]. 

In addition to nanoparticles, other precious metal catalyst structures have been investigated such as mesoporous nanostructured layers. In a series of publications Attard, Elliott, Bartlett, and co-workers described the formation of mesoporous Pt and PtRu films by lyotropic liquid crystalline phase templated electroless or electrochemical (faradaic) deposition [237-243]. Using non-ionic surfactants (e.g., polyethylene glycols such as C12EO8, CieEOs, and CisEOio) at concentrations above 30 wt% in order to assure the formation of a homogeneous liquid crystalline phase, the surfaetant moleeular aggregates in the bulk electrolyte could serve as templates for nanostruetured deposition of metal ions from the interstitial spaces. 

The methodology of particle synthesis can be categorized into three phases gas-, liquid-, and solid-phase methods. In order to control the properties of nanoparticles, it is necessary to precisely control the synthesis process. The colloidal process, in which solvents and surfactants are of great help in preventing particle aggregation and deposition on the wall, is the most reported for nanoparticle synthesis in a microreactor. This method is also one of the most utilized methods for nanoparticle synthesis that allows control of particle size, shape, and even crystal structure and crystallinity by controlling particle nucle-ation and growth. 

A new one phase method for the synthesis of uniform monodisperse crystalline Ag nanoparticles in aqueous systems was developed by using newly synthesized mono and dihydroxylated ionic liquids and cationic surfactants based on 1,3-disubstituted imidazolium cations and halogens anions. The hydroxyl functionalized ionic liquids and hydroxyl functionalized cationic surfactants simultaneously act both as the reducing and protective agent. By changing the carbon chain length, alcohol structure and anion of the hydoxy-functionalized 1,3-imidazolium based ionic liquids and the hydroxyl functionalized cationic surfactants the particle size, uniformity and dispersibility of nanoparticles in aqueous solvents could be controlled (Dorjnamjin et al, 2008). 

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