ORGANIZATION OF AN AMPHIPHILIC LINEAR DIBLOCK COPOLYMER AT THE AIR/WATER INTERFACE STUDIED BY NEUTRON REFLECTOMETRY

被引:21
作者
RICHARDS, RW [1 ]
ROCHFORD, BR [1 ]
WEBSTER, JRP [1 ]
机构
[1] RUTHERFORD APPLETON LAB, ISIS SCI DIV, DIDCOT OX11 0QX, OXON, ENGLAND
来源
FARADAY DISCUSSIONS | 1994年 / 98卷
关键词
D O I
10.1039/fd9949800263
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
Neutron reflectometry has been used to obtain the organization of a linear diblock copolymer at the air/water interface. To obtain the maximum information, a series of copolymers with approximately the same chemical composition but differing in isotopic labelling of the component blocks was synthesised. Each of these was spread on heavy water and a mixture of light and heavy water with zero reflective power for neutrons and the reflectivities were obtained at surface pressures of 2, 5 and 10 mN m(-1). Qualitative inspection of these reflectivity profiles suggests that a two-layer structure is formed with the poly(methyl methacrylate) block adjacent to the air. A more quantitative analysis using two-layer fits to the data generated by the optical matrix confirms this view but the parameters obtained are very sensitive to the quality of the fits. A direct analysis method has been attempted using the partial-structure-factor approach and using a Gaussian model for each layer we have been able to obtain layer dimensions, layer separations and the distribution of water in the poly(ethylene oxide)-rich lower layer which appears to be completely in the aqueous subphase.
引用
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页码:263 / 281
页数:19
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