Siloxane-based nanoparticles

Fig. 1 Schematic representation of the ODN-modifled siloxane-based nanoparticles. Blue-, polyorganosiloxane nanoparticle, with attached PEO (only one out of many shown) and subsequent coupling of oligo-DNA (ODN)...

Meltzer et al. (2001) showed direct evidence for long-range interactions between lanthanide impurity ions in embedded nanocrystals with the TLS s of the matrix based on hole burning data. The samples were prepared as follows monoclinic 23 run Y2C>3 0.1% Eu3+ nanocrystals, produced by condensation after laser evaporation, were dispersed in a siloxane polymer. Fig. 13 shows the temperature dependence of the width of spectral holes (khb), which were burned in the 5Do <- 7Fo transition of Eu3+ ions located on the c sites (582.8 nm)innanociys-tals embedded in polymer, in comparison with the case of the free, as-prepared nanocrystals having the same size. The embedded nanocrystals exhibit a drastic increase in hole width and a very different power-law behavior for the temperature dependence of the hole widths relative to similar isolated nanoparticles. The 7 3 temperature dependence of the hole width... 

Information provided in the PMN indicated that the siloxane-modified silica nanoparticles and siloxane-modified alumina nanoparticles would be used as additives. Based on test data and the substances physical properties, the EPA determined that there are concerns for lung effects from inhalation and systemic effects from dermal exposure. The PMN indicate worker inhalation exposure to the alumina nanoparticles was expected to be minimal inhalation exposure to the silica nanoparticles was not expected, and dermal exposure to both materials was also not expected. The EPA stated ... 

A novel nanocomposite membrane, poly dimethyl siloxane (PDMS)/Au was prepared for carbon dioxide/methane separation. Synthesis of stabilized nano particles is also reported. The nanoparticles were characterized by UV-visible spectroscopy and transmission electron microscopy (TEM). The hybrid membrane was characterized morphologically by scanning electron microscope (SEM) and the change in inter-segmental distance due to filler loading by wide angle X-ray diffraction patterns (WAXD). The gas transport properties were measured at different pressures and temperatures. The effects of filler loading on permselectivity, diffiisivity selectivity and solubility selectivity are reported for CO2/CH4 separation. Reverse selective phenomena of PDMS/Au nanocomposite membrane over the conventional PDMS membrane is explained based on sorption kinetics of CO2. 

Based on the above considerations effect of gold nanoparticles loading in polydimethyl siloxane matrix was examined for the separation of CO/CO2, CO/CH4 and CO2/CH4. The above gas mixtures are the product of syngas reaction and their separation is of great significance to industrial application in natural gas purification. PDMS have received considerable attention as potential membrane material for gas separation because of their high intrinsic permeability to gases and vapors. 

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