Langmuir. 2010 Mar 16;26(6):4357-67. doi: 10.1021/la903443p.
Previously, the synthesis of highly oriented pure double-gyroid nanoporous silica films has been demonstrated using evaporation-induced self-assembly (EISA) and dip-coating with a specialty triblock surfactant (PEO-PPO-alkyl) as the template. For these films, grazing-incidence small-angle X-ray scattering (GISAXS) was used to determine orientation and structure. However, GISAXS is not widely available, and we have observed significant batch-to-batch variability in the PEO-PPO-alkyl surfactants used. Here, we show for the first time: (1) synthesis of highly oriented pure double-gyroid nanoporous silica films using freely available EO(19)-PO(43)-EO(19) surfactant (Pluronic-P84) as the nanostructure-directing agent, (2) the use of spin-coating and dip-coating EISA to fabricate the double-gyroid films, and (3) the use of theta-theta X-ray diffractometers (commonly available and typically used for powder X-ray diffraction, PXRD) to identify the double-gyroid phase. Processing diagrams for P84 using dip-coating and spin-coating are shown in order to map the dependency of the nanostructure on solution composition, relative humidity, and solution aging time. In addition, an effect of the rate of evaporation during EISA is observed via dependence on the angular velocity in spin-coating. Also, through quantitative comparison of the GISAXS patterns with corresponding PXRD patterns, previously unexplained diffraction peaks in the PXRD patterns are shown to result from diffraction from crystallographic planes that are not parallel to the substrate (typically not observed in PXRD) due to the small angles involved and the nonzero acceptance angle of the PXRD Soller slits. These peaks provide a means to distinctly identify the double-gyroid phase using PXRD. The same trends relating aging-time-before-coating to the phase that forms via EISA are observed with EO(19)-PO(43)-EO(19) as was the case in previous studies using EO(17)-PO(14)-C(12). This shows the generality of use of aging time to synthesize nanoporous silica films with nonionic surfactants. Finally, a list of "tips and tricks" is provided to facilitate easy reproducible synthesis of double-gyroid nanoporous silica thin films in other laboratories.
先前，通过蒸发诱导自组装（EISA）和使用特殊的三嵌段表面活性剂（PEO-PPO-烷基）作为模板的浸涂，已经证明了高度取向的纯双连续各向异性纳米多孔硅薄膜的合成。对于这些薄膜，使用掠入射小角 X 射线散射（GISAXS）来确定取向和结构。然而，GISAXS 并不广泛可用，并且我们已经观察到所使用的 PEO-PPO-烷基表面活性剂在批次间存在显着的可变性。在这里，我们首次展示了：（1）使用自由可得的 EO(19)-PO(43)-EO(19)表面活性剂（Pluronic-P84）作为纳米结构导向剂合成高度取向的纯双连续各向异性纳米多孔硅薄膜，（2）使用旋涂和浸涂 EISA 来制备双连续各向异性薄膜，（3）使用θ-θ X 射线衍射仪（通常可用于粉末 X 射线衍射（PXRD））来识别双连续各向异性相。为了绘制纳米结构对溶液组成、相对湿度和溶液老化时间的依赖性，显示了使用浸涂和旋涂的 P84 的加工图。此外，通过在旋涂中对蒸发速率的依赖性，观察到 EISA 期间蒸发速率的影响。此外，通过与相应的 PXRD 图案的定量比较，显示了先前在 PXRD 图案中未解释的衍射峰是由于与基底不平行的晶面的衍射（由于涉及小角度和 PXRD Soller 狭缝的非零接受角，通常在 PXRD 中观察不到）所致。这些峰提供了一种使用 PXRD 来明确识别双连续各向异性相的方法。使用 EO(19)-PO(43)-EO(19)观察到与通过 EISA 形成的相有关的老化时间与以前使用 EO(17)-PO(14)-C(12)的研究相同的趋势。这表明使用老化时间来合成具有非离子表面活性剂的纳米多孔硅薄膜的通用性。最后，提供了一份“技巧和窍门”列表，以方便在其他实验室中轻松重现双连续各向异性纳米多孔硅薄膜的合成。
