Prepared mesoporous organosilicas PMOs

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... 

One-pot synthesis [11-14], in addition to the surface modification, is widely used for the preparation of framework-modified materials known as periodic mesoporous organosilicas (PMOs) [15]. They are synthesized by hydrolysis and condensation of bis(trialkoxysilyl) organic precursors and related compounds in the presence of both ionic and nonionic templates. In contrast to the conventional OMOs that possess surface organic groups [2, 8-14], the PMO framework contains Si-R-Si linkages (where R is an organic bridging spacer) [15]. 

Till now, the PMO was usually prepared under strongly acidic or basic conditions. Most PMOs usually need strong interaction between the surfactant micelles and hydrolyzed organosilicas for the formation of the mesoporous stracture. So, finding mild conditions for the synthesis of PMOs still remain significant challenges. Mild conditions, such as weak acidic or basic, could seriously decrease the interactions between surfactant micelles and hydrolyzed organosilicas which form the ordered mesoporous structure. Recently, li [69] reported the mild pH conditions for the synthesis of PMOs. 

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