Inorganic precursors, nature

Mercury, tin, lead, arsenic, and antimony form toxic lipophilic organometallic compounds, which have a potential for bioaccumulation/bioconcentration in food chains. Apart from anthropogenic organometallic compounds, methyl derivatives of mercury and arsenic are biosynthesized from inorganic precursors in the natural environment. 

Compared to sihca-based networks, nonsiliceous ordered mesoporous materials have attracted less attention, due to the relative difficulty to apply the principles employed to create mesoporous silica to nonsilica compositions. Other framework compositions are much more sensitive than silica to redox reactions, hydrolysis, or phase transformations. The reactivity of the inorganic precursors is much more difficult to control in the case of transition metal oxides, the reaction kinetics being much faster. Also, crystalline nonsiliceous frameworks are less prone to adapt the curvature of micellar aggregates, whereas the amorphous nature of silica allows for certain flexibility. 

Compared to amphiphilic core-shell molecular bmshes, bishydrophilic molecular bmshes have seldom been employed to template the ID nanostmctures. The key challenge lies in how to immobilize the inorganic precursors in the bmsh core in spite of the hydrophilic nature of the shell. That is, the precursor should interact differently with the core and the shell, that is, strongly with the core to get chemically immobilized, but weakly with the bmsh shell or, in an ideal case, not interact at all. This supposition is proven possible when a... 

When the hydrophobic/hydrophilic nature of the inorganic precursor is changed, the surfactant concentration in the concentrated phase can decrease to an extent where no ordered structures are observed. This phenomena is observed because the surfactant heads have stronger interactions with I2 than with other precursors. 

An overview of the precursors, process chemistry, and relative advantages and disadvantages of the three principal methods of inorganic electronic thin film preparation is shown in Table 2.1. Generally, sol-gel methods offer the greatest control over the nature of the solution precursor species, but they have involved... 

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