Introduction
Alkyl silanes are saturated compounds that consist of one or more silicon atoms linked to each other or one or more atoms of other chemical elements. A series of connected silicon atoms is called silicon skeleton or silicon backbone. The amount of silicon atoms is used to determine the size of the alkyl silane. Alkyl silanes are very active and have moderate biological activity. Alkyl silanes are widely used in the microelectronics and optoelectronics industries and the manufacture of solar cells, flat panel displays, and glass and steel coatings. High-tech applications of alkyl silanes continue to emerge, including the manufacture of advanced ceramics, composite materials, functional materials, biomaterials, high-energy materials, and so on. Alkyl silanes are becoming the basis for many new technologies, materials, and devices.
Applications
Material chemistry: Fabric coatings prepared from homogeneous mixture of fluorinated-decyl polyhedral oligomeric silsesquioxane (FD–POSS) and hydrolyzed fluorinated alkyl silane (FAS) exhibit significant self-healing, superhydrophobic and superoleophobic properties and the excellent durability against UV light, which may be useful for the development of innovative protective clothing for a variety of applications.
Fig.1. Photo of colored water (yellow), hexadecane (red), and tetradecane (blue) on the FD–POSS/FAS treated polyester fabric
In the presence of tetramethoxysilane, by a series of cohydrolysis and polycondensation of alkyl methoxy silanes with different functionalities and alkyl chain lengths, new alkyl siloxane multilayers can be successfully formed. Nanostructured materials can be constructed by a sol-gel reaction, which use monofunctional and bifunctional organosilanes as starting materials. It is clear that the co-condensation between alkyl methoxy silane and tetramethoxy silane in the precursor solution is essential for self-assembly into ordered nanocomposites. The expansion to other systems using various organoalkoxysilanes may lead to the formation of novel layered nanocomposite films with organic functional groups between the silica layers.
Organic chemistry: The development of (trifluoromethyl)trimethylsilane and other (perfluoroalkyl)trialkylsilanes as perfluoroalkylation reagents has begun. In general, the nucleophilic activation of silicon centers allows the transfer of perfluoroalkyl functional groups to various electrophiles. Under these conditions, perfluoroalkylated silanes behave as synthetic equivalent of "Rf-" and can therefore react with electrophiles.
Fig.2. Alkyl silane is used as perfluoroalkylation reagent
References
- Wang H, Xue Y, Ding J, et al. Durable, Self‐Healing Superhydrophobic and Superoleophobic Surfaces from Fluorinated‐Decyl Polyhedral Oligomeric Silsesquioxane and Hydrolyzed Fluorinated Alkyl Silane[J]. Angewandte Chemie International Edition, 2011, 50(48): 11433-11436.
- Shimojima A, Umeda N, Kuroda K. Synthesis of Layered Inorganic− Organic Nanocomposite Films from Mono-, Di-, and Trimethoxy (Alkyl) Silane−Tetramethoxysilane Systems[J]. Chemistry of materials, 2001, 13(10): 3610-3616.
