Poly(ester)s containing germanium and silicon in the main chain. 1. Langmuir monolayer characterization

Surface characterization of poly(ester)s containing germanium (Ge) or silicon (Si) in the main chain was studied. Surface pressure-area isotherms (p-A) at the air/water interface were obtained by monolayer compression at constant temperature. The molecular areas from the pressure-area isotherms were estimated for all polymers. At low surface concentrations poly(ester)s the characterization of monolayers was carried out according to the variation of the surface pressure as a function of the surface concentration; the behavior observed was described by the virial expansion development. In the semidilute region, the surface pressure variation was expressed according to the scaling laws as a power function of the surface concentration. It was found that the chemical structure of the poly(ester)s studied influences the type of the isotherms. The morphology of the monolayers was observed by Brewster angle microscopy (BAM). The molecular mechanics approach was used to obtain predictions about the local interaction energies between segments and to explain the minimum area values at the collapse point.