Association of block copolymers with dendritic and perfluorinated side chains in solution and at an interface

摘要

Block copolymers, poly(3,5-bis(3,5-bis(benzyloxy) benzyloxy)benzyl methacrylate-ran-dom-methacrylic acid)-block-poly(2-perfluorooctylethyl acrylate) [P(D_3MA,MAA)-b-PFA], which contain benzyloxy dendron and perfluorinated alkyl chains in their side chains, were synthesized. The products were characterized by differential scanning calorimetry and IR absorption spectroscopy, and their degrees of polymerization were determined with gel permeation chromatography, elemental analysis, and UV-vis spectroscopy. It was confirmed from transmission electron microscopic and atomic force microscopic observation that P(D_3MA,MAA)-b-PFAs were associated into polydisperse, spherical particles in a chloroform solution. The surface pressure-area isotherms of Langmuir monolayers at the air-water interface displayed hysteresis, which was remarkable for a P(D_3MA,MAA)-b-PFA with a medium substitution fraction of the dendron block. The molecular orientation at the air-water interface estimated from atomic force microscope images of Langmuir-Blodgett films depended on the substitution fraction: Whereas the atomic force microscope image of a Langmuir-Blodgett film of a copolymer with a medium substitution fraction showed a flat surface, that with the high fraction showed a zone texture.