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Full-Text Articles in Materials Chemistry
Macroporous Silica Using A “Sticky” Stöber Process, Rebecca Cademartiri, Michael A. Brook, Robert Pelton, John D. Brennan
Macroporous Silica Using A “Sticky” Stöber Process, Rebecca Cademartiri, Michael A. Brook, Robert Pelton, John D. Brennan
Rebecca Cademartiri
The generation of macroporous silica structures using a sol–gel process generally requires the presence of high molecular weight, water-soluble polymers. We demonstrate that significantly lower molecular weight poly(ethylene glycol) (PEG) polymers can drive a particle aggregation process to generate macroporous silica. Compared to unfunctionalized PEGs (HO–PEG–HO, molecular weight > 10 000 g mol−1), PEG polymers with allyl (A–PEG–A) or silyl end groups (CH2)3Si(OEt)3 (Si–PEG–Si), with molecular weights of 2000 g mol−1 or greater, lead to monolithic macroporous structures derived from aggregates of nearly monodisperse particles. Lower molecular weight (less than 1000 g mol−1) allyl or silyl PEG, or hydroxy-terminated PEG–OH, lead …
Organosilicas With Chiral Bridges And Self-Generating Mesoporosity, Andreas Ide, Rebecca Voss, Gudrun Scholz, Geoffrey A. Ozin, Markus Antonietti, Arne Thomas
Organosilicas With Chiral Bridges And Self-Generating Mesoporosity, Andreas Ide, Rebecca Voss, Gudrun Scholz, Geoffrey A. Ozin, Markus Antonietti, Arne Thomas
Rebecca Cademartiri
Amine-functionalized, chiral mesoporous organosilicas were prepared from a rationally designed precursor, which combines the functions of a network builder, a chiral latent functional group, and a porogen in one molecule. The precursors are formed by a convenient enantioselective hydroboration using (S)-monoisopinocampheylborane on an ethylene-bridged silica precursor. These precursors do self-organize when hydrolysis of their inorganic moiety takes place via an aggregation of their organic moiety into hydrophobic domains. After a condensation−ammonolysis sequence mesoporous organosilicas functionalized with chiral amine groups are obtained, with the complete chiral functionalities located at the pore wall surface and therefore accessible to chemical processes. The pore …
Synthesis And Characterization Of Highly Amine Functionalized Mesoporous Organosilicas By An “All-In-One” Approach, Rebecca Voss, Arne Thomas, Markus Antonietti, Geoffrey A. Ozin
Synthesis And Characterization Of Highly Amine Functionalized Mesoporous Organosilicas By An “All-In-One” Approach, Rebecca Voss, Arne Thomas, Markus Antonietti, Geoffrey A. Ozin
Rebecca Cademartiri
Mesoporous organosilicas (MOs) represent a promising class of organic–inorganic nanocomposites for a broad range of applications like catalysis, sensing, separation, or microelectronics. Their distinct feature is the presence of organic groups incorporated into the channel walls of a mesoporous structure. Here, we present a convenient “all-in-one” approach using silsesquioxane surfactant precursors for the functionalization of the channel walls with primary amine groups. The monomer is made by a hydroboration/aminolysis sequence on the base of a commercial monomer, with the template bound to the functionalization site by hydroboration and released after silica condensation and aminolysis. This combination ensures both the placement …
Heterostructures Of Polymer Photonic Crystal Films, Marc Egen, Rebecca Voss, Bernd Griesebock, Rudolf Zentel, Sergei Romanov, Clivia Sotomayor Torres
Heterostructures Of Polymer Photonic Crystal Films, Marc Egen, Rebecca Voss, Bernd Griesebock, Rudolf Zentel, Sergei Romanov, Clivia Sotomayor Torres
Rebecca Cademartiri
This paper describes ways to multilayer opaline films (opaline heterostructures) composed from functional opal layers of spheres with different lattice constants. At first various monodisperse colloidsboth cross-linked and un-cross-linkedwere prepared from methyl methacrylate, methyl α-chloroacrylate, and methyl α-bromoacrylate. These colloids can be crystallized into large, well-oriented opaline films with the help of a “drawing apparatus” by the method of crystallization in a moving meniscus. After annealing, a second opaline film can be crystallized on top of these films and so on. Electron microscopy inspection shows a sharp borderline between the sublayers and no disorder on both sides although the lattice …