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    Thin Films of Hydrophobically Modified Poly(N,N-dimethylacrylamide)

    Year: 2005

    Journal: Langmuir 2005, 21, 3940-3949, 20111221

    Authors: Mariana Beija, Paula Relagio, Marie-Therese Charreyre, A. M. Goncalves da Silva, P. Brogueira, J. P. S. Farinha, and J. M. G. Martinho

    Organizations: Centro de Quimica-Fisica Molecular, Instituto Superior Tecnico, 1049-001 Lisboa, Portugal, Unite Mixte CNRS-bioMerieux, ENS de Lyon, 46 allee d'Italie, 69364 Lyon Cedex 07, France, Centro de Quimica Estrutural, Instituto Superior Tecnico, 1049-001 Lisboa, Portugal, and Departamento de Fisica, Instituto Superior Tecnico, 1049-001 Lisboa, Portugal

    The behavior of a poly(N,N-dimethylacrylamide) hydrophobically modified by incorporating 0.33 mol % of a pyrenyl derivative, [4-(1-pyrenyl)butyl]amine hydrochloride (PY) and 3.56 mol % of dodecylamine (DO) has been studied at the air/water interface. Surface pressure-area isotherm measurements show that the film is initially anchored by the hydrophobic groups at the air-water interface with a pancake-like structure and, with increasing surface pressure, evolves to a quasi mushroom structure, finally reaching a brush configuration at high pressures. Monolayers of this polymer were transferred to silica substrates using the Langmuir-Blodgett (LB) technique at 5, 15, and 25mN/m. The properties of the LB films were studied by steady-state and time-resolved fluorescence as well as by atomic force microscopy. The results show that the aggregates formed at low pressures are disrupted by pressure increase, while the watersoluble poly(N,N-dimethylacrylamide) becomes dissolved in the water subphase.