Organization of Organic Molecules with Inorganic Molecular Species into Nanocomposite Biphase Arrays

Huo, Quan; Margolese, D.; Ciesla, Ulrike; Demuth, Dirk; Feng, Pingyun; Gier, Thurman E.; Sieger, Peter; Firouzi, Ali; Chmelka, Bradley F.; Schüth, Ferdi; Stucky, Galen D.

doi:10.1021/cm00044a016

Cited by 1,501 publications

(1,267 citation statements)

References 12 publications

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“…30 Since the NAM is synthesized from an acidic precursor solution containing HCl, CTAB and TEOS, the nanochannels contain chloride and bromide ions as counter anions of cetyltrimethylammonium (CTA) cation and/or a protonated surface silanol. 25,31 When solute anions are introduced into the nanochannels, adsorption of solute anions occurs via exchange with the anion which is associated with the CTA cation and/or protonated silanol. By this anion-exchange adsorption process, solutes in nanochannels are trapped in adsorption sites, and the amount of free solutes is decreased.…”

Section: Solute Dependence Of Permeation Flux In Watermentioning

confidence: 99%

Permeation Flux of Organic Molecules through Silica-surfactant Nanochannels in a Porous Alumina Membrane

et al. 2006

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Separation membranes are used in many fields ranging from medical science to industry, and much effort has been devoted to the development of new membranes with high qualities. [1][2][3] Recently, inorganic membranes have attracted much attention because of their superior mechanical strength, thermal stability and resistance to organic solvents. A variety of preparation and application methods of inorganic membranes have been reported. [4][5][6][7][8][9][10][11][12][13][14][15] Zeolites 4-8 and ceramics 9-14 are frequently used as sources of inorganic membranes. Zeolites are porous crystalline materials, which have a high surface area to volume ratio. Membranes made of zeolites are used for catalysts, 5 pervaporation 6,7 and high temperature separation of hydrocarbon isomer vapors. 8 Ceramics such as alumina are hard and heat-resistant materials made with nonmetallic minerals, and ceramic membranes for gas separation 13 and catalysts 14 have been synthesized.Mesoporous silica has also been adopted as a source material in the synthesis of inorganic membranes. 9,15 Mesoporous silica is an ordered material that has three different mesophases: lamellar, cubic and hexagonal. 16,17 In particular, the hexagonal mesophase possesses highly regular arrays of uniform-sized channels whose diameters are in the approximate range of 1 to over 10 nm depending on the surfactants and reaction parameters. Because of its porosity, high surface area, ordered pore arrangement and pore size uniformity, mesoporous silica has been the subject of many theoretical and applied studies. 18 For practical applications, the morphology of mesoporous silica is very important. The film is an ideal morphology for separation membranes, sensor 19,20 and optics. 21,22 Usually, mesoporous silica films are prepared on a flat substrate by dipor spin-coating methods. [23][24][25] However, in the case of hexagonal mesoporous silica, the channels are aligned parallel to the substrate surface, and transport of molecules across the film is not possible. In order to achieve separation, straight channels should be oriented perpendicular to the surface to transport molecules across the film. To solve this problem, instead of hexagonal mesoporous silica, some researchers have used cubic mesoporous silica to synthesize the inorganic membrane. 15,19 Recently, a porous anodic alumina membrane with a perpendicularly oriented silica-surfactant nanochannel assembly membrane (NAM) was synthesized. 26 The porous anodic alumina membrane has a packed array of columnar pores ranging from tens to hundreds of nanometers in diameter, and the channel direction of the columnar pores is perpendicular to the membrane.When a precursor solution containing cetyltrimethylammonium bromide (CTAB) surfactant and tetraethyl orthosilicate (TEOS) as a silica source is introduced into the alumina pores, highly ordered hexagonally arranged silica-surfactant nanochannels with pores of 3.4 nm diameter are assembled inside the alumina pores. The channel direction of mesoporous silica is predomi...

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Section: Solute Dependence Of Permeation Flux In Watermentioning

confidence: 99%

Permeation Flux of Organic Molecules through Silica-surfactant Nanochannels in a Porous Alumina Membrane

et al. 2006

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“…Methods to modify the pore size of the mesoporous materials include the post synthesis treatment, 2 using different surfactant molecules (template) with different chain lengths 3 and employing organic solvents as swelling agents. 4 The addition of swelling agents, such as TMB, alkanes, 5,6 has been proved to be the most effective way in expanding the pore size of MCM-41 silicas (2-10 nm). Recently, the nonionic triblock copolymers templated SBA-15 silicas have attracted great interests due to their larger pores, thicker pore walls and therefore higher hydrothermal stabilities.…”

mentioning

confidence: 99%

“…In the case of MCM-41, where the traditional cationic surfactant was used, the pore size would enlarge with the increase of alkane chain length. 5,6 This is possibly related to the nature of the interactions between different surfactants and alkanes. It is well known that the nonionc copolymer surfactants (e.g.…”

mentioning

confidence: 99%

Alkanes-assisted low temperature formation of highly ordered SBA-15 with large cylindrical mesopores

et al. 2005

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Highly ordered SBA-15 silicas with large cylindrical mesopores (y15 nm) are successfully obtained with the help of NH 4 F by controlling the initial reaction temperatures in the presence of excess amounts of alkanes.With the discovery of M41s, 1 great efforts have been made on the construction of texture controllable mesoporous materials. Among them, tailoring the pore size of the mesoporous materials has been one of the hot issues for the purpose of providing a good performance for specific applications, such as the adsorption/ separation of bulky molecules, the immobilization of enzymes as well as the catalytic transformation reactions of macromolecules, etc. Methods to modify the pore size of the mesoporous materials include the post synthesis treatment, 2 using different surfactant molecules (template) with different chain lengths 3 and employing organic solvents as swelling agents. 4 The addition of swelling agents, such as TMB, alkanes, 5,6 has been proved to be the most effective way in expanding the pore size of MCM-41 silicas (2-10 nm). Recently, the nonionic triblock copolymers templated SBA-15 silicas have attracted great interests due to their larger pores, thicker pore walls and therefore higher hydrothermal stabilities. 7 Meanwhile, the pore size of SBA-15 could be tuned in the range of 7-30 nm by using TMB as expander. However, extensive studies show that a phase transition from highly ordered SBA-15 (7-12 nm) to mesoporous cellular foams (MCF) with large nodded pore structures (y22-42 nm) occurred with increasing amounts of TMB. 8 Therefore, it is still essential to find other methods of tuning the pore size of highly ordered mesoporous materials. In other works, organic auxiliary chemicals (e.g., DMF, 9 alkanes 10,11 ) have also been investigated. Unfortunately, the maximum pore size of the highly ordered SBA-15 is only ca. 12 nm (with decane). Furthermore, when alkanes with shorter chain length (such as nonane, octane, etc.) were employed, disordered MCF silicas were produced under the temporal reaction conditions. 10 Up to now, to our knowledge, the synthesis of highly ordered SBA-15 silicas with cylindrical pore sizes larger than 12 nm has rarely been reported. Herein, it is demonstrated for the first time that the pore size of highly ordered SBA-15 could be continuously expanded to y15 nm by carefully controlling the initial reaction temperatures with excess amounts of alkanes (from nonane to hexane). To our knowledge, it is the largest cylindrical mesopore diameter with regard to highly ordered SBA-15 silicas.As a typical synthesis procedure, 2.4 g of EO 20 PO 70 EO 20 (P123) was dissolved in 84 ml HCl solution (1.30 M), followed by the addition of 0.027 g of NH 4 F. The mixture was then stirred at 288 K to yield a clear solution. Different alkanes (with a constant alkane/P123 molar ratio of y240) and 5.5 ml TEOS were premixed and then introduced into the solution under stirring. The above mixture was stirred at a given temperature for 20 h, and then transferred into an autoclave for furthe...

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“…To address this problem, the silica particles can be modified by applying a additional stable silica coating (post-coating). The dye-doped silica particles would then be stable in organic or aqueous solutions, and could be further functionalized and bioconjugated with biomolecules for bioanalysis [10,29].…”

Section: Resultsmentioning

confidence: 99%

A facile and general approach for the synthesis of fluorescent silica nanoparticles doped with inert dyes

Mu¹,

Wu²,

Lai³

et al. 2011

Chin. Sci. Bull.

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A general and facile approach was developed for the synthesis of almost monodisperse fluorescent silica nanoparticles (NPs) doped with inert dyes, which are organic fluorophores that are strongly fluorescent but are hydrophobic or lack a covalent binding group. The prepared NPs were mesoporous and the dye molecules were encapsulated in the pores via hydrophobic interaction with the CTAB template. The NPs were stable and highly fluorescent in aqueous solution, and have potential applications in bioanalysis and fluorescence encoding.

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Organization of Organic Molecules with Inorganic Molecular Species into Nanocomposite Biphase Arrays

Cited by 1,501 publications

References 12 publications

Permeation Flux of Organic Molecules through Silica-surfactant Nanochannels in a Porous Alumina Membrane

Permeation Flux of Organic Molecules through Silica-surfactant Nanochannels in a Porous Alumina Membrane

Alkanes-assisted low temperature formation of highly ordered SBA-15 with large cylindrical mesopores

A facile and general approach for the synthesis of fluorescent silica nanoparticles doped with inert dyes

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