POSS nanoparticles

Tuning of the pre-tilt angle at the interface was also demonstrated by doping commonly used polyimide alignment layers with POSS nanoparticles [339]. In addition, the fabrication of a tunable liquid crystal flat microlens was achieved by placing a drop of a nematic liquid crystal doped with POSS nanoparticles onto a substrate inducing planar alignment (local HAN mode) [340]. Simultaneously, Takatoh and co-workers extended this concept to a series of metal oxide... 

Fig. 7 Examples of polyhedral oligomeric silsesquioxane (POSS) nanoparticles used to induce homeotropic alignment in nematic liquid crystals...

Recently, Chen and co-workers also presented a combination of photo- and nanoparticle-induced alignment, where the homeotropic alignment induced by POSS nanoparticles can be changed into planar alignment by adsorption of a photo-excited azo-dye [346-348]. 

Lee B-J, lana SC. Strengthening of polyolefins by bottom-up self-assembly of POSS nanoparticles, ANTEC, conference proceedings. Society of Plastics Engineers 2008. 

Laser Emission from Gain Media Incorporating POSS Nanoparticle... 

The presence of POSS nanoparticles was found to enhance the laser action of (fyes of very different families both polar (Rhodamine 6G, Rhodamine 640, Sidforhodamine B, LDS722, LDS730) and non-polar (Perilene Red, PM567, PM597) with respect to the effectiveness recorded in pure oiganic solvents and polymeric solutions pumped under the same experimental conditions (Figure 6). 

To assess this qnestion in the present case, we characterized in detail the laser-induced spectroscopy of PM567 dye both in liquid and solid solutions with and without POSS nanoparticles, pumped rmder the same experimental conditions. The pump pulses were now incident on the samples at a 30° angle and the laser excitation energy was gradually increased from 0.9 to 6 mJ/pulse. The emission from the front-face of the sample was collected with an optical fiber, sent to an spectrometer with 0.1 nm resolution and detected with a CCD camera. 

Figure 2. The structure of a PSS-(3-(2-Aminoethyl)amino)propyl-Heptaisobutyl substituted POSS nanoparticle (Sigma-Aldrich Corp., St. Louis, MO, USA).

POSS molecules have been easily incorporated into polymers via blending, grafting or copolymerization. Incorporation of POSS particles into polymer matrices leads to chemical cross-linking, where the nanofiller particles are covalently bonded with polymer. In a second approach, where the POSS nanoparticles are physically blended with polymer using melt mixing or solvent casting methods, the... 

Zhang, Y.W. and Ye, Z.B. (2008a) Homogeneous polyhedral oligomeric silsesquioxane (POSS)-suppdiimine complex and synthesis of polyethylenes end-tethered with a POSS nanoparticle via ethylene living polymerization. Chemical Communications, 1178-1180. 

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