Hierarchically ordered porous silica composites: Ordering on three different lengths with three dimensional pore inter-connectivity
Studies in Surface Science and Catalysis, cilt.154 A, ss.408-415, 2004 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Özet
- Cilt numarası: 154 A
- Basım Tarihi: 2004
- Dergi Adı: Studies in Surface Science and Catalysis
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.408-415
- Anahtar Kelimeler: 3-dimensional interconnectivity, Hierarchically ordered porous silica, Macro, Meso, Micropores
- Atatürk Üniversitesi Adresli: Hayır
Özet
A room temperature synthesis of hierarchically ordered porous silica is reported using colloidal spheres and a tri-block co-polymer surfactant as templates. Macropore size and ordering were controlled using a close-packed monolith of polystyrene latex spheres whereas mesoscale ordering was controlled using a surfactant containing different EO-PO-EO groups (F127: EO 108PO70EO108 or P123: EO20PO 70EO20) in the presence of a co-surfactant (n-butanol or n-pentanol). The thickness and pore interconnectivity of macropores was controlled either using a silica gel containing such surfactants or using a colloidal suspension of silica or zeolite nano particles as building units. Macrospheres with interconnected windows (70-130nm) are formed when surfactant containing silica gel was used as building units whereas hollow silica macrospheres without interconnecting windows are formed when nano particles were used as building units. XRD, TEM and N2 adsorption results suggest the presence of mesopores. Nitrogen adsorption results indicate the presence of micropores (<2nm) in the mesoporous walls. The mesopores are interconnected with macropores and micropores. The surface area of such materials was improved when the polystyrene latex template was removed by solvent extraction before calcination at a specific temperature. The probable mechanism of formation of such hierarchically ordered porous silica is presented.