Biocidal mesoporous SBA-15 particles decorated with Ag nanowires: Nucleant role in PLLA crystallization and antimicrobial transfer of their activity to the resultant biobased PLLA-SBA15@Ag composites

Different composites based on an L-rich poly(lactic acid) (PLLA) and mesoporous SBA-15 functionalized with silver (SBA-15@Ag) are prepared by a solvent casting protocol, and subsequently processed as films by compression molding. Characterization of hybrid SBA-15@Ag particles shows that Ag is mainly incorporated as nanowires within the nanometric silica channels, and is able to provide its antimicrobial character to these hybrid particles. PLLA crystallinity, crystallization ability and the polymorphs able to be developed are strongly dependent on cooling rate and in less extent on silica content. These hybrid particles exert an important nucleating and reinforcing effect in the resultant composites. They also show very interesting and remarkable antimicrobial features, which are transferred to the PLLA composites. The most important antimicrobial activity is found against P. aeruginosa, E. coli and C. parapsilosis, Gram negative bacteria and yeast, respectively.