The kinetics of surface film formation at the air-water interface after spreading of small unilamellar dioleoylphosphatidylcholine liposomes are studied by measuring the evolution of surface parameters : surface pressure pi and surface potential DELTAV. Various proposed kinetic models are analysed. The surface transformation of perfectly closed spherical liposomes into a surface film is accelerated by various chemical reactions. An important biologically relevant case is studied : photodynamic peroxidation of lipids by methylene blue. A theoretical approach describing the coupling of this chemical interaction with the process of surface transformation is developed.