Poly(lactic acid) (PLA) is a very attractive polymer for food packaging application. In this work we tried to develop a smart PLA film, especially to improve its potential food applications providing antibacterial properties by means of functionalization of the film surface with cardanol-based vesicle nanodispersion obtained by an environmental-friendly process. We used cardanol-based nanovesicles loaded with porphyrin molecules itself cardanol functionalized, in order to prepare a composite material that can act as potential 'smart film' as acid indicator: The film changes its colour according to the acid atmosphere it reveals thanks to the conformational change of porphyrin. Starting from commercial PLA pellets, films were extruded and cardanol-based nanovescicles embedded with porphyrin were deposited on these PLA films by simple casting of the aqueous vescicular nanodispersion. The functionalized PLA films were then studied by mechanical testing. SEM-FEG characterization, and UV-visible measurements were performed to investigate the presence of cardanol-based nanodispersion on the film and the acid response of porphyrin. © 2015 IEEE.