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Confinement and Cross-Linking of 1,2-Polybutadiene in Two Dimensions at the Air-Water Interface
Anne-Sophie Vaillard1, Alae El Haitami1, Lisa B Dreier2
1Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528) , Institut des Matériaux, CY Cergy Paris Université , 5 mail Gay-Lussac Neuville/Oise , Cergy-Pontoise Cedex 95031 , France.
Abstract:
Langmuir monolayers of 1,2-polybutadiene (PB) were investigated by means of surface pressure-area isotherms, Brewster angle microscopy (BAM) observations, and sum-frequency generation (SFG) spectroscopy. A homogeneous and stable monolayer is formed 1.5 h after PB spreading provided that both light and oxygen are present. This was attributed to a slight oxidation of the PB at the air-water interface. The cross-linking of PB under UV photoirradiation was then studied. SFG spectroscopy demonstrates the in situ formation of a two-dimensional network. From surface pressure-area characterizations and BAM experiments, the cross-linked PB monolayer appears significantly denser and more rigid than the non-irradiated monolayer. Atomic force microscopy images reveal an increase by a factor of three in the root-mean-square roughness of the irradiated monolayers compared with the non-irradiated ones.
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