Amphiphilic polymers of reversed duckweed type were synthesized, and their behaviour in monolayers at the air-water interface was studied. The relationship between the chemical structure of the polymers and their behaviour at the air-water interface was discussed. The UV-visible spectra of this kind of polymer in solution and in Langmuir-Blodgett (LB) films were explained by the molecular exciton theory. The orientation of mesogen groups incorporated in the LB film was confirmed by polarized UV-visible spectra. The photovoltaic properties of these LB films was studied by surface photovoltage spectroscopy.