Nanobuilding blocks based on the [OSiO1.5]x (x= 6, 8, 10) octasilsesquioxanes

Laine, Richard M.

doi:10.1039/b506815k

Cited by 422 publications

(305 citation statements)

References 97 publications

(154 reference statements)

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“…Furthermore, the shape and volume persistency of the heads might impose packing constraints under confined environments (such as thin films), thus providing access to unconventional nanopatterns. DPOSS-PS 35 that exhibits a DG nanostructure in the bulk state was first studied in thin films. As shown in the TEM image of Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Although computational modeling has predicted versatile phase behaviors and unique self-assembled morphologies (31)(32)(33), the potential of this class of materials has remained largely unexplored experimentally due to the difficulty in their precise synthesis in large quantity (34). Compact and rigid molecular nanoparticles (MNPs) with specific symmetry and precise structure provide access to perfect building blocks for the polar heads (30,35,36). They include, but are not limited to, polyhedral oligomeric silsesquioxane (POSS) (37,38) and [60]fullerene (C 60 ) (39,40) derivatives.…”

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confidence: 99%

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Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Yue

Hsieh

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

202

163

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The engineering of structures across different length scales is central to the design of novel materials with controlled macroscopic properties. Herein, we introduce a unique class of self-assembling materials, which are built upon shape-and volume-persistent molecular nanoparticles and other structural motifs, such as polymers, and can be viewed as a size-amplified version of the corresponding small-molecule counterparts. Among them, "giant surfactants" with precise molecular structures have been synthesized by "clicking" compact and polar molecular nanoparticles to flexible polymer tails of various composition and architecture at specific sites. Capturing the structural features of small-molecule surfactants but possessing much larger sizes, giant surfactants bridge the gap between small-molecule surfactants and block copolymers and demonstrate a duality of both materials in terms of their self-assembly behaviors. The controlled structural variations of these giant surfactants through precision synthesis further reveal that their selfassemblies are remarkably sensitive to primary chemical structures, leading to highly diverse, thermodynamically stable nanostructures with feature sizes around 10 nm or smaller in the bulk, thin-film, and solution states, as dictated by the collective physical interactions and geometric constraints. The results suggest that this class of materials provides a versatile platform for engineering nanostructures with sub-10-nm feature sizes. These findings are not only scientifically intriguing in understanding the chemical and physical principles of the self-assembly, but also technologically relevant, such as in nanopatterning technology and microelectronics. giant molecules | shape amphiphiles | hybrid materials | microphase separation | colloidal particles P hysical properties of materials are dictated by the hierarchical arrangements of atoms, molecules, and supramolecular assemblies across different length scales. The construction and engineering of structures at each length scale, especially at the 2-to 100-nm scale (1), are critically important in achieving desired macroscopic properties. As the traditional top-down lithography techniques face serious challenges in fabricating 2D and 3D nanostructured materials with sub-20-nm feature sizes (2), the bottom-up approach based on self-organization or directed assembly of functional molecules provides a promising alternative. The past decades have witnessed the development of diverse self-assembly building blocks ranging from small-molecule surfactants (3), block copolymers (4), and dendrimers (5) to DNAs (6, 7), peptides (8), and proteins (9). Notably, these motifs have enabled the programmed self-assembly of nanomaterials as demonstrated in DNA-coated nanoparticles (10-13). These studies have greatly improved our understanding of the thermodynamics and kinetics of self-assembly processes and opened enormous possibilities in modern nanotechnology.Noncovalent interactions, such as hydrogen bonding, amphiphilic effect, π-π interacti...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Yue

Hsieh

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

202

163

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“…[17][18][19][20][21][22][23][24] In polar solvents, POSS can form a globular conformation and create a distinct hydrophobic space around the POSS core. [25][26][27][28] Such structural features can contribute to reduce the packing density and isolating the distal ion pairs.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic study of POSS-based ionic liquids with various numbers of ion pairs

Tanaka

Ishiguro

Chujo

2011

Polym J

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We have previously reported a polyhedral oligomeric silsesquioxane (POSS)-based room temperature ionic liquid (IL) that shows a melting temperature below 25 1C. The connection of ion pairs to POSS can significantly improve the thermal stability and decrease the melting temperatures of the ion pairs. To understand the mechanism of these changes induced by POSS, we studied the thermal properties of POSS derivatives with variable numbers of imidazolium-carboxylate ion pairs. Initially, it was found that a modified POSS with a larger number of ion pairs could be a thermally stable, room temperature IL. From the series of thermodynamic and conformational analyses, we concluded that the star-shaped distribution of ion pairs originating from the cubic framework are necessary to express the characteristic changes in the thermal properties of ion pairs connected to POSS.

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“…The char then slowly oxidizes at higher temperatures in air but remains relatively stable if heated in nitrogen. 53), 67) Several reasons can be cited for why the ceramic yield is lower than theory. One reason is that some of the starting reagents might be lost to sublimation in the TGA, e.g.…”

Section: Thermal Analysis (Tga/dta) Of the 1:1 Ohsmentioning

confidence: 99%

Microporous inorganic/organic hybrids via oxysilylation of a cubic symmetry nanobuilding block [(HMe2SiOSiO1.5)8] with RxSi(OEt)4−x

Pan

Doan

et al. 2015

J. Ceram. Soc. Japan

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The B(C 6 F 5 ) 3 catalyzed Piers-Rubinsztajn (oxysilylation) reaction of the cubic symmetry Q-cage [(HMe 2 SiOSiO 1.5 ) 8 ] with ethoxysilanes in hexane forms microporous 3-D networks coincident with ethane evolution. Slow drying provides monoliths whereas fast drying provides powders. The reaction is most efficient if initiated at 60°C for 5 min and then allowed to progress at ambient. The products offer high specific surface areas [SSAs > 700 m 2 /g, e.g. with Si(OEt) 4 ], with micropores of 0.62.0 nm, mesopores of 240 nm, total pore volumes µ 0.5 cc/g, and thermal stabilities to 320°C. Changes in reaction conditions (times, solvent volumes, catalyst concentrations) do not significantly change product properties pointing to rapid and complete reaction as evidenced by the near absence of residual SiH under all conditions for 1:1: SiH:SiOEt ratios. RSi(OEt) 3 gives similar 3-D microporous gels. Smaller R groups give higher SSAs than those with large R groups; however, R = n-octyl is not porous. Rigid, bridged compounds [(EtO) 3 SiRSi(OEt) 3 ] (R = phenyl, biphenyl) offer high SSAs whereas flexible bridges [R = (CH 2 ) 2 or 8 ] give reduced SSAs. All materials were characterized by FTIR, TGA, XRD and BET. XRD studies show periodicities suggesting some long range ordering as might be expected for reactions with cubic symmetry Q 8 cages. However, the fast reaction rates likely generate kinetic rather than thermodynamic products that cannot be expected to exhibit high degrees of ordering. Gel affinities for specific organics were studied showing some preferential ability to absorb specific solvents for example the 1:1 OHS:vinylSi(OEt) 3 gels were more selective for toluene than the 1:1 OHS:TEOS gels.

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Nanobuilding blocks based on the [OSiO1.5]x (x= 6, 8, 10) octasilsesquioxanes

Cited by 422 publications

References 97 publications

Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Thermodynamic study of POSS-based ionic liquids with various numbers of ion pairs

Microporous inorganic/organic hybrids via oxysilylation of a cubic symmetry nanobuilding block [(HMe<sub>2</sub>SiOSiO<sub>1.5</sub>)<sub>8</sub>] with R<i><sub>x</sub></i>Si(OEt)<sub>4−</sub><i><sub>x</sub></i>

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Nanobuilding blocks based on the [OSiO1.5]x (x= 6, 8, 10) octasilsesquioxanes

Cited by 422 publications

References 97 publications

Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Thermodynamic study of POSS-based ionic liquids with various numbers of ion pairs

Microporous inorganic/organic hybrids via oxysilylation of a cubic symmetry nanobuilding block [(HMe<sub>2</sub>SiOSiO<sub>1.5</sub>)<sub>8</sub>] with R<i><sub>x</sub></i>Si(OEt)<sub>4&minus;</sub><i><sub>x</sub></i>

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Microporous inorganic/organic hybrids via oxysilylation of a cubic symmetry nanobuilding block [(HMe<sub>2</sub>SiOSiO<sub>1.5</sub>)<sub>8</sub>] with R<i><sub>x</sub></i>Si(OEt)<sub>4−</sub><i><sub>x</sub></i>