Infrared dichroism measurements on the alkyl chain packing of an ionic detergent intercalated between silicate layers

被引:17
作者
Binder, H
Kohlstrunk, B
Brenn, U
Schwieger, W
Klose, G
机构
[1] Univ Leipzig, Fak Phys, Inst Expt Phys 1, D-04103 Leipzig, Germany
[2] Univ Halle Wittenberg, Inst Tech Chem & Makromol Chem, D-06108 Halle, Germany
关键词
metal silicate hydrate layers; infrared linear dichroism; order parameter; orthorhombic subcell; tilt angle; trimethylammonium group;
D O I
10.1007/s003960050351
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Microcrystals of the metal silicate hydrate ilerite orient macroscopically on the surface of a ATR-crystals and thus, are accessible for infrared linear dichroism measurements. We present first results which indicate that the alkyl chain packing and the orientation of the polar group of dodecyl-trimethylammoniumbromide (DTAB) intercalated between silicate layers can be determined in terms of infrared order parameters. The properties of DTAB can be modulated by the relative humidity of the surrounding atmosphere and by temperature. Upon heating DTAB undergoes a phase transition from a paraffin-like solid to a fluid phase. The former is characterized by the orthorhombic perpendicular packing of the frozen alkyl chains with tilted long axes. The interactions between the ionic groups of the surfactant and that of the host matrix stabilize the lamellar arrangement of DTAB in the crystalline and in the fluid phases.
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页码:1098 / 1109
页数:12
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