Preparation and characterization of SiO2/CMC/Ag hybrids with antibacterial properties

Amorphous hybrids based on sodium salt of carboxymethyl cellulose (CMC) and tetraethoxysilane (TEOS) containing silver nanoparticles were prepared by sol–gel method. The amorphous structure, morphology and antibacterial behavior were clarified. The thermal stability of obtained hybrids decreased with the increase in silver content from 0.5 to 1.5 wt%. Infrared spectra of the material suggest that the main interaction between the cellulose ether and silica network is via hydrogen bonds (bands at ∼3540 and 3625 cm−1). According to UV–vis spectra the silver is present in two different states Ag+ (absorption band at ∼210 nm) and Ag0 (band at ∼300 nm). The different sizes of silver particles are present as clusters. It was demonstrated that these hybrids have a well pronounced antibacterial activity against B. subtilis and E. coli K12. Even the hybrid with 0.5 wt% Ag has efficient antibacterial activity for both Gram-positive and Gram-negative bacteria.