Synthesis and characterization of an antibacterial powder based on the covalent bonding of aminosilane-stabilized silver nanoparticles to a colloidal silica

DELL´ERBA, I.E.; MANSILLA, A.Y.; HOPPE, C.E.; WILLIAMS, R.J.J.

JOURNAL OF MATERIALS SCIENCE

SPRINGER

Lugar: Berlin; Año: 2016 vol. 51 p. 3817 - 3823

0022-2461

Stable dispersions of silver nanoparticles (AgNPs) were synthesized employing glycerol as both a solventand reducing agent, and 3-aminopropyltrimethoxysilane (APTMS) as a stabilizer. Average sizesvaried between 13 and 55 nm, depending on the molar ratioof APTMS/Ag. Terminal alkoxysilanes reacted with OHgroups of glycerol leading to the covalent bonding ofglycerol moieties to the chain ends of the stabilizer. Thisproduced extremely stable colloidal dispersions fromwhich NPs could not be extracted with solvents immisciblewith glycerol (as THF). Ag NPs were covalently bonded tothe surface of a colloidal silica by hydrolysis/condensationof terminal Si?O?C bonds of the stabilizer with superficialSiOH bonds of silica. TEM images revealed the presenceof individual NPs and small clusters of NPs attached to thesilica surface. These clusters were presumably generatedby intermolecular reactions among chain ends of the stabilizerproducing Si?O?Si bonds. The antibacterial propertiesof the resulting powder were confirmed byconventional tests employing a culture of Escherichia Coli.