عنوان مقاله [English]
نویسندگان [English]
Block copolymers and cetyltrimethylammonium bromide were used as templates in nano silica structure formation like MCM-41)Mobil Composition of Matter), SBA16 )Santa Barbara Amorphous) and a new compound namely SPB )silicone mesoporous particles, prepared by sol-gel method using PPG-PEG-PPG block copolymer) to compare the porosity and regularity of the products together. In this work tetraethylorthosilicate )TEOS), as silica source and alcohol as surface modifying agent were used because of having the main advantage, compared to an ionic template such as etyltrimethylammonium bromide, in producing larger pores and thicker walls for holding larger catalytic molecules in their pores or increasing their resistance towards fragmentation. In order to study the copolymer as a template, SPB structure was prepared and compared with SBA16 which was found to have broader pore-size distribution and smaller specifc surface area. Using alcohol in particle production resulted in higher formation rate of micelles with improved morphology. Nitrogen adsorption-desorption, X-ray diffraction and electron scanning microscopy confrmed the mesoporous structure and regularity of these synthesized materials. Finally a mechanism is proposed for the formation of these structures.
کلیدواژهها [English]
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