DPPC/E-CyP-OBu mixture was initially prepared. The Teflon barriers were stopped when a surface pressure equal to 20 mN/m wass obtained. The M375L4.1540 mW LED, (LED Power Output 1540mW, full power used) with a central wavelength of 375 nm and a bandwidth (FWHM) of 9 nm, was placed above the film in order to irradiate the total surface. The evolution of the surface pressure was recorded as a function of time.