Oriented Growth of ETS-4 Films Using the Method of Secondary Growth

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• 作者：Bilge Yilmaz ; Kristin G. Shattuck ; Juliusz Warzywoda ; and Albert Sacco ; Jr.
• 刊名：Chemistry of Materials
• 出版年：2006
• 出版时间：March 7, 2006
• 年：2006
• 卷：18
• 期：5
• 页码：1107 - 1112
• 全文大小：585K
• 年卷期：v.18,no.5(March 7, 2006)
• ISSN：1520-5002

文摘

Oriented growth of polycrystalline ETS-4 films on porous titania substrates was investigated using themethod of secondary growth, utilizing synthesis mixtures with compositions of 3.6SiO₂/1TiO₂/5.5Na₂O/xH₂SO₄/230.2H₂O, where x = 4.4 or x = 3.6. Dense seed layers, obtained in situ by hydrothermal synthesis(x = 4.4), were partially (a, c)-out-of-plane oriented. Films were prepared in just one secondary growthstep. Films developed by evolutionary, epitaxial growth of seed crystals and were highly (x = 4.4) b-out-of-plane oriented. Highly b-out-of-plane oriented ETS-4 films were also grown from dense, partiallyb-out-of-plane oriented seed layers on porous -alumina substrates using identical synthesis mixtures.[Shattuck et al., Microporous Mesoporous Mater. 2006, 88, 56]. These findings suggest that the filmorientation is dictated by the secondary growth conditions and is not determined by the seed layerorientation. This was attributed to the highly anisotropic growth rates of ETS-4 and the limited growthspace provided by dense seed layers. Overall, these results indicate that by effectively decoupling nucleationfrom seed crystal growth, and by providing conditions for the fastest growth of crystals along the b-directionin a confined space, it is possible to fabricate highly b-out-of-plane oriented ETS-4 films for advancedapplications.