Amphiphilic Block Copolymers of Poly(ethylene oxide) and Poly(perfluorohexylethyl methacrylate) at the Water Surface and Their Penetration into the Lipid Monolayer

Abstract

Poly(ethylene oxide) (PEO) and poly(perfluorohexylethyl methacrylate) (PFMA) containing amphiphilic block copolymers have been investigated for their interfacial behavior and their penetration into 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) monolayer at the air/water interface by measuring surface pressure (π)/area (A) isotherms in conjunction with infrared reflection absorption spectroscopy (IRRAS). The π/A isotherms of the block copolymers show pressure regimes corresponding to different conformations of the polymer chains, i.e., a pancakelike conformation at low surface coverage and a brush conformation at high surface pressures. The plateau in π/A isotherms of the block copolymers, (i.e. a phase transition from the pancakelike conformation to the brush conformation) becomes less and less pronounced with a decrease in the PEO block length. The π/A isotherm of the DPhPC monolayer shows only a liquid expanded phase state at the air/water interface at all surface pressures. The DPhPC monolayer pe...