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Herein, it is reported how pseudomorphic transformation of divinylbenzene (DVB)‐bridged organosilica@controlled pore glasses (CPG) offers the possibility to generate hierarchically porous organosilica/silica hybrid materials. CPG is utilized to provide granular shape/size and macroporosity and the macropores of the CPG is impregnated with organosilica phase, forming hybrid system. By subsequent pseudomorphic transformation, an ordered mesopore phase is generated while maintaining the granular shape and macroporosity of the CPG. Surface areas and mesopore sizes in the hierarchical structure are tunable by the choice of the surfactant and transformation time. Two‐dimensional magic angle spinning (MAS) NMR spectroscopy demonstrated that micellar‐templating affects both organosilica and silica phases and pseudomorphic transformation induces phase transition. A double‐layer structure of separate organosilica and silica layers is established for the impregnated material, while a single monophase consisting of randomly distributed T and Q silicon species at the molecular level is identified for the pseudomorphic transformed materials.

Mesoporous silica (SiO2) and periodic mesoporous organosilica (PMO) with divinylbenzene (DVB)- and divinylaniline (DVA)-bridge groups are studied by solid-state NMR and molecular dynamics simulations to examine the influence of the surface chemistry on the interfacial interactions and the assembly structures of the surfactants. The NMR signals of the surfactants inside the mesopores appear at different chemical shift values depending on the organic bridging groups. Two-dimensional NMR spectroscopy shows that the surfactants assemble as micellar structures, where the polar head groups directly interact with the pore walls, and the interaction strength of the surfactants with pore wall is in the order of SiO2 >DVA-PMO > DVB-PMO. To elucidate the functional dependence of the interfacial structure of SiO2 and PMOs, the radial distribution function is calculated from molecular dynamics simulations, which provides individual atomic correlations quantitatively. For SiO2, the surfactant head is preferentially adsorbed to the inorganic layer with extended aliphatic tail group packing, whereas the adsorption of the surfactant head group to the pore wall is weaker for PMOs. We find that the hydrophobic interaction between DVB and the surfactant tail, which is stronger than that in the case of polar DVA, weakens the interaction between the surfactant head and organic layer for DVB-PMO more than for DVA-PMO. From the conformational analysis, we directly observe a more abundant gauche defect of the surfactant in DVA-PMO than in DVB-PMO. The upfield NMR shift in DVB-PMO is revealed by more planar aromatic ring orientation, which is caused by the steric effect between the organic groups. Our study suggests that the hydrophobicity and bulkiness of the organic bridge can be exploited in the design of PMOs for molecular machines, absorbents, and enzyme immobilization materials.

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A dielectric matrix with embedded Si‐nanoparticles may show strong luminescence depending on nanoparticles size, surface properties, Si‐excess concentration and matrix type. Ion implantation of Si ions with energies of a few tens to hundreds of keV in a SiO2 matrix followed by thermal annealing was identified as a powerful method to form such nanoparticles. The aim of the present work is to optimize the synthesis of Si‐nanoparticles produced by ion implantation in SiO2 by employing MeV ion irradiation as an additional annealing process. The luminescence properties are measured by spectrally resolved photoluminescence including PL lifetime measurement, while X‐ray reflectometry, atomic force microscopy and ion beam analysis are used to characterize the nanoparticle formation process. The results show that the samples implanted at 20%‐Si excess atomic concentration display the highest luminescence and that irradiation of 36 MeV 127I ions affects the luminosity in terms of wavelength and intensity. It is also demonstrated that the nanoparticle luminescence lifetime decreases as a function of irradiation fluence. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)