Nano-sized container

The word liposome comprises two terms (from Greek—lipid [fat] and soma [body]). It does not in itself denote any size characteristics. Furthermore, the term liposome does not necessarily mean that it must contain lipophobic contents, such as water, although it usually does. The vesicles may be conceived as microscopic (or nano-sized) containers of carrying molecules (drugs) from one place to another. The structures are suitable for both transporting water-soluble or water-insoluble drugs. Since the lipids used are biocompatible molecules, this may also enhance their adsorption and penetration into the cells. 

Incorporation of small molecules into the hollow cavities of carbon nanotubes (CNTs) generates a new class of hybrid materials, which show potential applications ranging from nano-size containers for chemical reactions or for drug delivery to data storage and possibly high-temperature superconductors [181]. Because of their unique structure, such materials are called nano peapods [182]. 

FIGURE 16.44 The structure of a molecular magnet. The nano-size molecular torus contains 84 manganese atoms and is approximately 4 nm in diameter. The manganese atoms are bonded to groups of carbon atoms in the form of acetate ions, water molecules, and chlorine atoms. In this molecule the manganese atoms act as terromagnets. 

A new composite containing montmorillonite and zeolite Beta is prepared by in situ crystallization. Nano-zeolite Beta grows on montmorillonite. The composite possesses a dual system of micropore, originated from zeolite Beta, and mesopore of size around 50nm, due to the abundance of interspace formed by montmorillonite laminaes. Compared with catalyst MoNi/Beta, more i-C8 is produced on catalyst MoNi/composite, when n-Cg is used for feedstock for hydroisomerization. This results from the high diffusion created by composite and the short channel of nano-size zeolite Beta. 

Making uniform nano-sized metal oxide particles is also of interest. Such particles could have a higher specific surface area and a higher density of surface defects than those made by conventional preparation methods. This could be beneficial to their catalytic properties. If the oxide particle is multi-component, then such nano-sized particles, each containing the various components would provide more intimate contact or... 

Schneider, N.K., Mooney, C., Baron, B., Hampshire, S. (1999), Oxynitride glass composites containing nano-size SiC , Brit. Ceram. Proc., 60(1), 401-2. 

In our studies, the nano-sized sihca was synthesized using cheap sodium orthosilicate and sodiirm metasihcate rather than expensive alkoxysilanes. An inverse microemulsion containing NP-5/NP-9 as surfactant and cylcohexane or petroleum ether as the oil was used to carry out the hydrolysis and condensation of sodium orthosilicate or metasilicate using an acidic medium [152, 153]. The spherical silica particles of size 10-20 nm were obtained in a system using cyclohexane as the oil and with sodium orthosihcate of 0.01-0.1 M [152]. The particle size increased as the concentration of sodium orthosihcate and the pH were increased. Sihca particles prepared in basic conditions were more uniform in size than those prepared in an acidic medium. But calcined sihca powders with larger specific areas (350-400 mVg) were obtained for those prepared in an acidic medium. 

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