Metamorphic Channels in Periodic Mesoporous Methylenesilica

Asefa, Tewodros; MacLachlan, Mark J.; Grondey, H.; Coombs, Neil; Ozin, Geoffrey A.

doi:10.1002/(sici)1521-3757(20000515)112:10<1878::aid-ange1878>3.0.co;2-4

Cited by 32 publications

(8 citation statements)

References 38 publications

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“…Periodic mesostructured organosilicas (PMOs) [138] are a relatively new class of functional mesoporous material receiving a great deal of attention in recent years [139], and the Ozin group has been one of the leaders in this field [140]. In some ways, the PMO concept is a logical extension of the co-condensation process, the key difference being that the PMO materials are built around functional organo di-or tri-silanes.…”

Section: Periodic Mesostructured Organosilicasmentioning

confidence: 99%

The synthesis of functional mesoporous materials

Fryxell

2006

Inorganic Chemistry Communications

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Section: Periodic Mesostructured Organosilicasmentioning

confidence: 99%

The synthesis of functional mesoporous materials

Fryxell

2006

Inorganic Chemistry Communications

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“…[11][12][13] These bridging organic groups impart unique chemical, biological, optical, and dielectric properties to PMO and distinguish PMO from its pure siliceous counterpart. 14,15 We use methane PMO, with a -CH 2 -bridge, as an archetype to demonstrate our patterning technique because at a temperature higher than 400 °C, the transformation of bridging -CH 2 -groups into terminal -CH 3 groups hydrophobizes the surface of the pore wall 10,16,17 and exposes the terminal methyl groups for subsequent plasma treatment. Another PMO that can be similarly hydrophobized is 3-ring PMO; in contrast, ethane and ethene PMO do not possess this ability.…”

Section: Resultsmentioning

confidence: 74%

Secrets revealed — Spatially selective wetting of plasma-patterned periodic mesoporous organosilica

et al. 2012

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Abstract:We report a simple method to pattern wetting properties on thin films of periodic mesoporous organosilica (PMO). Hydrophobic methane PMO thin film was covered by masks and exposed to oxygen plasma to make unmasked area hydrophilic. The wettability patterns could be revealed only when the films were immersed in water or exposed to moisture. We expect that our method would extend the utility of PMO to such areas as sensing and information security.

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“…The first report of methylene-bridged PMOs was by Asefa et al in 2000. [54] Longer chain alkylene PMOs, such as alkylene spacers containing urea functionalities or hexylene spacers, were not reported until the mid-2000s to early 2010s. [55][56][57][58] Researchers found that it is often difficult to synthesize highly ordered PMOs containing long alkylene moieties due to solubility limitations.…”

Section: Synthesis Of Chiral Nematic Mesoporous Organosilica With Alkmentioning

confidence: 99%

Iridescent Chiral Nematic Mesoporous Organosilicas with Alkylene Spacers

Terpstra

Arnett

Manning

et al. 2018

Advanced Optical Materials

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surfactants and inorganic precursors, it has been possible to create mesoporous materials with different symmetries and pore sizes, and diverse compositions. [5,8] For example, using chiral surfactants as a liquid crystal template has created chiral mesoporous materials with twisted helical structures. [13] In 1999, three research groups independently reported on the incorporation of organic groups into mesoporous silica by using (R′O) 3 SiRSi(OR′) 3 precursors in the place of Si(OR) 4 precursors for the sol-gel condensation. [7,9,14] It proved possible to construct periodic mesoporous silica with organic groups directly integrated into the walls of the mesoporous structure. [11,[15][16][17][18][19][20][21][22][23] Sol-gel processing of silicate materials is highly versatile-it can incorporate various types of precursors and can be carried out under a variety of reaction conditions (e.g., variable pH, temperature, concentration, and solvent mixtures). [24] Therefore, mesoporous organosilica materials have attracted increasing interest for applications including catalysis, [1,25] metal scavenging, [26] chromatography, [27] and biomedical applications. [2] Cellulose nanocrystals (CNCs) obtained from sulfuric-acidcatalyzed hydrolysis of biomass are remarkable materials. [28,29] In 1951, Rånby isolated the crystalline regions within plant cellulose microfibers to form colloidal CNCs with nanoscale dimensions. [28] CNCs have impressive mechanical properties that arise from their high crystallinity and large aspect ratios. [30] Remarkably, CNCs also form a chiral nematic liquid crystal in water. [31] This order can be retained upon drying the aqueous suspension to give a colored, iridescent film. [32] The CNCs arrange into a Bouligand structure, where the crystallites themselves are aligned in layers, but twist with a characteristic helical pitch, P. It is the repeating helicoidal structure that leads to diffraction of circularly polarized light from the CNC films. [33] Many researchers are making new materials that take advantage of the unique properties of CNCs. [30,[34][35][36][37][38][39][40][41][42][43][44][45][46][47] In 2010, we discovered that films of mesoporous silica with chiral nematic structure could be prepared using CNCs as a template. [20] When Si(OR) 4 is condensed with CNCs in water, the resulting composite film contains silica and a chiral nematic assembly of CNCs. CNCs can be removed from the composite materials using pyrolysis, leaving behind thin films of iridescent mesoporous silica with a chiral nematic arrangement of pores inside the glass. These materials are of interest Mesoporous organosilica films with chiral nematic structures are prepared with a bridging urea group and with alkylene bridges, where the length of the alkylene bridge varies from C 1 -C 6 . To synthesize these materials, cellulose nanocrystals (CNCs) are used as liquid crystal templates, which coassemble with the organosilica precursor to give composite materials with a chiral nematic structure of CNCs embedded within. Remova...

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Metamorphic Channels in Periodic Mesoporous Methylenesilica

Cited by 32 publications

References 38 publications

The synthesis of functional mesoporous materials

The synthesis of functional mesoporous materials

Secrets revealed — Spatially selective wetting of plasma-patterned periodic mesoporous organosilica

Iridescent Chiral Nematic Mesoporous Organosilicas with Alkylene Spacers

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