Semitransparent composite films were prepared made from TiO2 nanotubes in chitosan (CS) matrix. Hydrothermally synthesized titanium nanotubes (TiNTs) were dispersed in chitosan matrix in order to produce film-forming solutions at 0.05 and 0.10% w/v. Structural, topological, optical and thermal properties of these films were evaluated. The antimicrobial activity of films against Salmonella enterica serovar Typhimurium, Escherichia coli (Gram-negatives) and Staphylococcus aureus (Gram-positive) was also investigated. Fourier transform infrared (FTIR) spectra showed effective site-selective interactions between chitosan and TiNTs. TiNTs prevented the degradation of films, avoiding the oxidization of the glucosamine ring. Characterizing techniques such as, Scanning electron microscopy energy dispersive spectroscopy (SEM-EDS) line profile and atomic force microscopy (AFM) were used to examine the TiNTs dispersion within the film. The morphological analysis indicated that the TiNTs were well dispersed and became clustered proportionally to the weight percentage of TiNTs used in the composites. The UV-Vis spectra showed that TiNTs increased the film absorption in the UV region and the light barrier properties of films remained stable over the storage period. Photoacoustic spectroscopy (PAS) was used to study these films, nondestructively for their thermal effusivity (e). The films were effective in reducing the microbial concentration in the liquid culture for all bacteria tested. The effectiveness was found to dependent on the bacterial strain and TiNTs content. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3503-3515, 2010