Flodström Katarina, Wennerström Håkan, Teixeira Cilâine V, Amenitsch Heinz, Lindén Mika, Alfredsson Viveka
Physical Chemistry 1, Lund University, P.O. Box 124, SE- 221 00, Lund, Sweden.
Langmuir. 2004 Nov 9;20(23):10311-6. doi: 10.1021/la0482958.
The mechanism of formation of two different cubic mesoporous silica materials formed with Pluronic triblock copolymers is investigated with in situ time-resolved small-angle synchrotron X-ray scattering, in situ time-resolved 1H nuclear magnetic resonance, and time-resolved transmission electron microscopy. The materials studied are the micellar cubic (Imm) SBA-16 formed with Pluronic F108 and the bicontinuous cubic (Iad) silica material formed with Pluronic P103 and NaI. The formation mechanisms of the two cubic structures are shown to be dissimilar. For the Imm material, in the early stages of the synthesis, flocs of unordered micelles are observed, but areas where the micelles have started to order are also present. With time, there is an increase in order; however, there is a coexistence of unordered micelles and ordered material all through this study. The bicontinuous cubic silica is formed via a different path. The system is phase-separated already before the addition of the silica source, which implies that a concentrated phase is present, acting as the structure director of the Iad structure. The results are compared with earlier reports on the formation of the hexagonal SBA-15 material.
利用原位时间分辨小角同步加速器X射线散射、原位时间分辨1H核磁共振以及时间分辨透射电子显微镜，研究了由普朗尼克三嵌段共聚物形成的两种不同立方介孔二氧化硅材料的形成机制。所研究的材料是由普朗尼克F108形成的胶束立方（Imm）SBA - 16以及由普朗尼克P103和NaI形成的双连续立方（Iad）二氧化硅材料。结果表明，这两种立方结构的形成机制不同。对于Imm材料，在合成的早期阶段，观察到无序胶束的絮凝物，但也存在胶束开始有序排列的区域。随着时间的推移，有序度增加；然而，在整个研究过程中，无序胶束和有序材料共存。双连续立方二氧化硅是通过不同的路径形成的。在添加硅源之前，体系已经发生相分离，这意味着存在一个浓相，作为Iad结构的结构导向剂。将结果与早期关于六方SBA - 15材料形成的报道进行了比较。
