Optimization of the interfacial agent content in biocidal titania-isotactic polypropylene nanocomposites is performed by evaluating their structural, thermal, optical, and biocidal properties. The balance between the photochemistry (photokilling) behavior and the thermal proper-ties is achieved in the nanocomposites with an incorporation of 2 wt% in inorganic nanoparticles (TiO2) using a compatibilizer content ranging from 50 to 80 wt.% with respect to the titania amount