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Array of QAS functionalized polyhedral oligomeric silsesquioxanes ..

the synthesis of polyhedral oligomeric ..

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Polyhedral oligomeric silsesquioxanes are a class of ..

A new polyhedral oligomeric silsesquioxane (POSS) methacrylate monomer, 1-(3-(methacryloyloxy)propyl)dimethylsiloxy-3,5,7,9,11,13,15-hepta(isobutyl)pentacyclo-[9.5.1.13,9.15,15.17,13]octasiloxane ((i-Bu)7POSS-OSiMe2-MA, 1), with a flexible spacer between the cubic POSS cage and methacrylate group was synthesized to reduce steric strain and thus achieve polymethacrylates (poly(POSS-MA)s) with high molecular weight (MW). Atom transfer radical polymerization (ATRP) of 1 at high monomer concentration (1 M, corresponding to ca. 85 wt % of 1) led to polymers with the absolute number-average MW, determined by multiangle laser light scattering, n,MALLS = 2 350 000 (and apparent MW, measured by gel permeation chromatography with linear poly(methyl methacrylate) (PMMA) standards, n,GPC = 550 000). Optimization of the reaction conditions, including the ATRP catalyst, targeted degrees of polymerization, monomer concentrations, as well as a monomer feeding, resulting in the first well-defined high MW polymers with POSS moieties.

Synthesis of Polyhedral Oligomeric Silsesquioxane …
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AB - Abstract Highly de-bundled multiwalled carbon nanotube (MWCNT) polymer nanohybrids were obtained via ionic assembling of a novel POSS-polyimidazolium-ionic liquid (POSS = polyhedral oligomeric silsesquioxanes) with oxidized MWCNTs. The synthesis, accomplished by a simple bilayer chloroform/water metathetical reaction process, was promoted by the high surfactant properties of POSS-imidazolium-polyionic liquid, which assisted the effective de-bundling, dispersion and purification of the as prepared POSS@MWCNT polymers in organic media, via a surface coating mechanism. The presence of remarkably intense radial breathing modes (RBMs) in Raman spectra, both in solution and as solid, corroborates the effectiveness of the de-bundling process induced by the amphiphilic POSS polymeric ionic liquid (polyIL). This was, further, substantiated by scanning and transmission electron microscopy images. The nonlinear optical (NLO) behavior of POSS@MWCNT was investigated by Z-scan technique, which revealed a remarkable susceptibility χ(3) of 2.38·10-7 esu mainly due to a dispersive effect. A good optical limiting (OL) performance, under a 532 nm pulsed excitation, was observed as well.

Polyfluorenes with appended polyhedral oligomeric silsesquioxanes ..

Synthesis and Characterization of Polyhedral Oligomeric Silsesquioxane (POSS) Based Amphiphiles
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Novel molecular design for organic–inorganic emulsifiers has been developed based on an incompletely condensed polyhedral oligomeric silsesquioxane (POSS). Hydrophilic poly(ethylene) glycol chains were introduced to the three silanol groups of heptaisobutyl trisilanol POSS. The obtained amphiphilic POSSs worked as good emulsifiers, and the emulsions were stable for at least 1 month without coalescence of the droplets. The simple synthetic procedure, the well-defined three-dimensional structure and the obtained stable emulsions are advantageous in developing organic–inorganic hybrid materials.

Polyimide chain-end-tethered polyhedral oligomeric silsesquioxane (POSS) self-assembled into zigzag shaped cylinders or lamellae due to the demixing between the polar−polar interacted imide segments and the van der Waals force interacted POSS molecule. By covalently combining nanoporous POSS molecules with polyimide in forming nanocomposites, the dielectric constant of polyimide was reduced without degrading its mechanical properties.

octasilane polyhedral oligomeric silsesquioxane via ..

15/09/2016 · Synthesis and Use of Metallized Polyhedral Oligomeric ..
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Nanoporous polyhedral oligomeric silsesquioxanes (POSS) containing amine groups (NH2−POSS) were reacted with poly(amic acid) having anhydride end groups to form porous POSS/polyimide nanocomposites. The van der Waals interaction between tethered POSS molecules is incompatible with the polar−polar interaction of imide segments, resulting in a self-assembled system of zigzag shaped cylinders or lamellas about 60 nm long and 5 nm wide, as determined by transmission electron microscopy. The incorporation of 2.5 mol % nanoporous POSS results in a reduction of the dielectric constant of the polyimide nanocomposite from 3.40 for the pure polyimide to 3.09 without any degradation in mechanical strength.

Hepta(3,3,3-trifluoropropyl) polyhedral oligomeric silsesquioxane (POSS)-capped poly(N-isopropylacrylamide) (PNIPAAm) telechelics with variable lengths of PNIPAAm midblocks were synthesized by the combination of reversible addition−fragmentation chain transfer polymerization (RAFT) and the copper-catalyzed Huisgen 1,3-cycloaddition (i.e., click chemistry). The POSS-capped trithiocarbonate was synthesized and used as the chain transfer agent for the RAFT polymerization of N-isopropylacrylamide. The organic−inorganic amphiphilic telechelics were characterized by means of nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Atomic force microscopy (AFM) shows that all the POSS-capped PNIPAAm telechelics exhibited microphase-separated morphologies, in which the POSS terminal groups were self-assembled into the microdomains and dispersed into the continuous PNIPAAm matrices. The POSS nanodomains could behave as the physical cross-linking sites and as a result the physical hydrogels were formed while these POSS-capped PNIPAAm telechelics were subjected to the solubility tests with water. These physical hydrogels possessed well-defined volume phase transition phenomena and displayed rapid reswelling and deswelling thermoresponsive behavior compared to control PNIPAAm hydrogel.

cost of polyhedral oligomeric silsesquioxanes in recent years has opened ..
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  • Synthesis of High Molecular Weight Polymethacrylates …

    Synthesis and Dielectric Properties of Polyimide-Chain-End Tethered Polyhedral Oligomeric Silsesquioxane Nanocomposites

  • Synthesis and characterization of an octaimidazolium …

    Synthesis and characterization of photoluminescent vinylbiphenyl decorated polyhedral oligomeric silsesquioxanes.

  • Synthesis and Dielectric Properties of Polyimide-Chain …

    Title : Synthesis of Polyimides Produced from Novel High Temperature Polyhedral Oligomeric Silsesquioxane Dianilines

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Polyhedral Silsesquioxanes - Springer

T1 - Highly untangled multiwalled carbon nanotube@polyhedral oligomeric silsesquioxane ionic hybrids: Synthesis, characterization and nonlinear optical properties

Polyhedral oligomeric silsesquioxane ..

N2 - Abstract Highly de-bundled multiwalled carbon nanotube (MWCNT) polymer nanohybrids were obtained via ionic assembling of a novel POSS-polyimidazolium-ionic liquid (POSS = polyhedral oligomeric silsesquioxanes) with oxidized MWCNTs. The synthesis, accomplished by a simple bilayer chloroform/water metathetical reaction process, was promoted by the high surfactant properties of POSS-imidazolium-polyionic liquid, which assisted the effective de-bundling, dispersion and purification of the as prepared POSS@MWCNT polymers in organic media, via a surface coating mechanism. The presence of remarkably intense radial breathing modes (RBMs) in Raman spectra, both in solution and as solid, corroborates the effectiveness of the de-bundling process induced by the amphiphilic POSS polymeric ionic liquid (polyIL). This was, further, substantiated by scanning and transmission electron microscopy images. The nonlinear optical (NLO) behavior of POSS@MWCNT was investigated by Z-scan technique, which revealed a remarkable susceptibility χ(3) of 2.38·10-7 esu mainly due to a dispersive effect. A good optical limiting (OL) performance, under a 532 nm pulsed excitation, was observed as well.

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