The present invention relates to thin polymeric films containing nanoparticles with tunable absorption in the visible and near infrared (NIR) region. When these films are irradiated with NIR sources, they show a pronounced photo-thermal effect. Said effect allows a localized temperature increase, which can be controlled both spatially and temporally. Once the irradiation source has been turned off, the temperature returns within a few seconds to the initial value and then raises again as soon as the film is irradiated again. These films can be used as reusable medical devices, with a controllable and reproducible heating profile, in particular thermal or heating patches.
