Linear Long Alkyl Chain Substituted POSS Cages: The Effect of Alkyl Chain Length on the Self-Assembled Packing Morphology

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• 作者：Ellen L. Heeley ; Darren J. Hughes ; Youssef El Aziz ; Peter G. Taylor ; Alan R. Bassindale
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：June 25, 2013
• 年：2013
• 卷：46
• 期：12
• 页码：4944-4954
• 全文大小：643K
• 年卷期：v.46,no.12(June 25, 2013)
• ISSN：1520-5835

文摘

The self-assembled long-range ordering, packing morphology and thermal behavior of a series of polyhedral oligomeric silsesquioxanes (POSS) T₈ cage systems with long n-alkyl chain pendant groups is presented. State-of-the-art time-resolved small- and wide-angle X-ray scattering (SAXS/WAXS), thermal and optical techniques were used to elucidate their morphology. X-ray scattering showed long-range crystalline ordering where the alkyl chains align in an axial disposition from the POSS core giving a 鈥渞od-like鈥?self-assembled packing morphology with a length-scale correlating to the overall molecular dimensions. Phase transitions observed by thermal methods were comparable to those seen in the crystallization of bulk n-alkanes. Optical measurements and crystallization kinetics confirmed a lamellar macromorphology again being similar to the crystal structure of bulk n-alkanes. This study reveals for the first time, the direct effect that the alkyl chain length has on the self-assembled crystalline packing morphology of this novel and potentially commercially relevant, series of POSS systems.