2-dimensional surface properties of ω-methoxy poly(ethylene glycol) macromonomer and homopolymer at the air-water interface

Two-dimensional surface properties of the macromonomer have been investigated using a Langmuir Film Balance. The macromonomer forms an expanded film, similar to hydrophilic polymers, with a maximum limiting area (A(0)) of 8.75 Angstrom(2) molecule(-1) at 25 degrees C that probably arises from the more expanded conformation. The macromonomer undergoes a transition, causing a change of orientation at the interface, in the pressure region 2-6.5 mN m(-1), corresponding to respective areas of 8.4 and 5.5 Angstrom(2) molecule(-1). The polymerization reaction of the macromonomer promotes hydrophobic behaviour indicated by a large collapse pressure, pi(c) (10 mN m(-1)) and maximum surface pressure, pi (16 mN m(-1)) in homopolymeric film. Monolayer studies also suggest that the size of the homopolymer is 41-48 times larger than that of the macromonomer at the air-water interface. (C) 2000 Elsevier Science B.V. All rights reserved.