Long-Range Nanometer-Scale Organization of Semifluorinated Alkane Monolayers at the Air/Water Interface

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• 作者：Lisa Bardin ; Marie-Claude Faur茅 ; Denis Limagne ; Corinne Chevallard ; Oleg Konovalov ; Eduardo J. M. Filipe ; Gilles Waton ; Marie Pierre Krafft ; Michel Goldmann ; Philippe Fontaine
• 刊名：Langmuir
• 出版年：2011
• 出版时间：November 15, 2011
• 年：2011
• 卷：27
• 期：22
• 页码：13497-13505
• 全文大小：977K
• 年卷期：v.27,no.22(November 15, 2011)
• ISSN：1520-5827

文摘

We have determined the structure formed at the air鈥搘ater interface by semifluorinated alkanes (C₈F₁₇C_mH_2m+1 diblocks, F8Hm for short) for different lengths of the molecule (m = 14, 16, 18, 20) by using surface pressure versus area per molecule isotherms, Brewster angle microscopy (BAM), and grazing incidence x-ray experiments (GISAXS and GIXD). The behavior of the monolayers of diblocks under compression is mainly characterized by a phase transition from a low-density phase to a condensed phase. The nonzero surface pressure phase is crystalline and exhibits two hexagonal lattices at two different scales: a long-range-order lattice of a few tens of nanometers lateral parameter and a molecular array of about 0.6 nm parameter. The extent of this organization is sufficiently large to impact larger scale behavior. Analysis of the various compressibilities evidences the presence of non organized molecules in the monolayer for all 2D pressures. At room temperature, the self-assembled structure appears generic for all the F8Hm investigated.