Organosilicas, nanoporous

In conclusion, we first described the one step synthesis of nanoporous organosilica powders functionalized with a Non Linear Optical chromophore in the channel pore (azobenzene diethylphosphonate). These powders have been totally characterized and present a meso-porosity with a wormlike structure. Thin films monofunction-alised with NLO chromophore in the channel pores or bifunctionalized (NLO in the channel pores/erbium salt in the framework) were also prepared in one step and characterized by Grazing Incidence Small angle X-ray Scattering (GISAXS) and X-ray reflectivity. Interestingly, while the monofunctional thin film presents a lamellar structure, the bifunctional one (channel pores/framework)... 

Comotti A, Bracco S, Valsesia P, Beretta M, Sozzani P (2010) Fast molecular rotor dynamics modulated by guest inclusion in a highly organized nanoporous organosilica. Angew Chem Int Ed 49 1760-1764... 

Mixed micelles can be exploited as templates for preparation of nanoporous materials. Oligomeric alkyl-ethylene oxide surfactant (Polyoxyethylene (2) cetyl ether, B52), and ionic surfactant (cetyltrimethylammonium bromide, CTAB) form mixed micelles that self-assemble into well-ordered hexagonal and bimodal mesostructures. These systems can be used as templates to synthesize hydrothermally stable organized periodic mesoporous organosilicas (PMOs). The X-ray diffraction (XRD), TEM, BET, NMR and hydrothermal studies have been used to investigate the effects of B52 on the formation of various PMOs. The addition of B52 in the surfactant solution improves... 

Indeed, the compositional flexibility of mesoporous materials is such that it is possible to prepare mesoporous organosilicas with organic groups (e.g., ethene) inside the pore walls. An unusual property of mesoporous silicas is that they can themselves be used as templates for the formation of mesoporous carbon. The mesoscopi-cally ordered nanoporous (or mesoporous) carbon molecular sieves are prepared by carbonizing sucrose (or other carbon precursors) inside the pores of mesoporous silica molecular sieve. The mesoporous carbon is obtained after subsequent removal of the silica template by dissolution in HF (hydrofluoric acid) or NaOH (sodium hydroxide) solution. 

Castricum, H.L., Paradis, G. G., Mittelmeijer-Hazeleger, M.C., Bras, W., Eeckhaut, G., Vente, J.F., Rothenberg, G., and ten Elshof, f.E. (2014) Tuning the nanopore structure and separation behavior of hybrid organosilica membranes. Microporous Mesoporous Mater., 185, 224-234. 

Trammell SA, Zeinali M, Melde BJ et al (2008) Nanoporous organosilicas as preconcentration materials for the electrochemical detection of trinitrotoluene. Anal Chem 80 4627-4633... 

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