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An efficient pH-responsive carrier system has been constructed by oppositely charged ionic interaction between carboxylic acid modified SBA-15 silica rods and polyelectrolyte. Active molecules such as vancomycin can be stored and released from the pore voids of SBA-15 by changing pH values at will. The amount of vancomycin stored in the pores of sample based on carboxylic acid modified SBA-15 rods and poly(dimethyldiallylammonium chloride) is up to 36.4 wt % at pH 6.8. When the pH is at mild acidity, vancomycin is steadily released from the pores of SBA-15. Both nitrogen adsorption-desorption isothems and X-ray diffraction patterns show that this system possesses stable mesostructure, which will be considered an interesting alternative to a polymeric delivery system.

A significant size effect on the mechanical properties of GaAs nanowires (NWs) is reported. A remarkable elastic strain of ≈11% for NWs with diameters of 50–150 nm and obvious plastic deformation in NWs with diameters ≤25 nm are revealed. The Young’s modulus of the NWs can be more than double that of bulk GaAs.

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Crystals of zeolites with intricate micropores have been widely used in industry as heterogeneous catalysts, in particular as solid acid catalysts in the fields of oil refining and petrochemistry. However, relatively small individual micropores in zeolites such as Beta, ZSM-5, and Y strongly influence mass transport to and from the active sites located within them, severely limiting the performance of industrial catalysts. [1,2] [19]). However, the use of these materials is rather limited owing to the difficult separation of nanosized zeolite crystals from the reaction mixture,[3] the complexity of the templates used for the synthesis of ultralarge-pore zeolites, [6][7][8][9] and the relatively low thermal and hydrothermal stability of ordered mesoporous materials. [17][18][19][20][21][22][23][24][25][26][27][28] More recently, mesoporous zeolites from nanosized carbon templates have also been successfully synthesized, [29][30][31][32] but their industrial applications are still limited by the complexity of the synthetic procedure involved and the hydrophobicity of the carbon templates.Herein, we demonstrate a facile, controllable, and universal route for the synthesis of hierarchical mesoporous zeolites templated from a mixture of small organic ammonium salts and mesoscale cationic polymers. The route involves a one-step hydrothermal synthesis, and the templated mixture is homogeneously dispersed in the synthetic gel. Importantly, these novel zeolites exhibit excellent catalytic properties compared with conventional zeolites. This work may give an entry to the synthesis of hierarchical mesoporous zeolites that reveal fast mass transport, with potential application in industrial catalysis.Beta zeolite is generally synthesized from a small organic template of tetraethylammonium hydroxide (TEAOH). In the present strategy, hierarchical mesoporous Beta zeolite (Beta-H) was crystallized in the presence of TEAOH and a mesoscale cationic polymer, polydiallyldimethylammonium chloride (PDADMAC). For comparison, conventional Beta zeolite was prepared in the absence of cationic polymer by a similar procedure.The X-ray diffraction (XRD) pattern of calcined Beta-H (Figure 1a) shows well-resolved peaks in the 4-40° range, characteristic for the Beta zeolite structure.