TETHERED ADSORBING CHAINS - NEUTRON REFLECTIVITY AND SURFACE PRESSURE OF SPREAD DIBLOCK COPOLYMER MONOLAYERS
TETHERED ADSORBING CHAINS - NEUTRON REFLECTIVITY AND SURFACE PRESSURE OF SPREAD DIBLOCK COPOLYMER MONOLAYERS
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DOI：
10.1021/la00011a047
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发表时间：
1995-11-01
期刊：
影响因子：
3.9
通讯作者：
VANWELL, AA
中科院分区：
文献类型：
--
作者：
BIJSTERBOSCH, HD;DEHAAN, VO;VANWELL, AA
Spread monolayers of diblock copolymers of styrene and ethylene oxide at the air-water interface were studied by surface pressure measurements and neutron reflectivity, as a function of coverage sigma and chain length N. The surface pressure data have three regions, one at low coverage, where a relatively sharp increase due to increasing intermolecular interaction is found, a more gently increasing part at intermediate coverage, where the poly(ethylene oxide) block gradually desorbs to form a blush, and a sharply increasing part at high coverage, where the blush is compressed. The neutron reflectivity measurements, taken in the intermediate and high coverage regions, confirm the presence of a brush with a thickness scaling, by approximation as sigma(1/3). These brushes could be compressed by a factor of about 5 without desorption occurring. The observations are in good agreement with numerical calculations based on a mean field lattice model for terminally anchored, adsorbing chains. These calculations predict a gradual change in the average configuration from a flat, adsorbed state to a brush consisting of stretched chains.
