Antimicrobial cotton fibers prepared by tempo-mediated oxidation and subsequent silver deposition

Abstract

In this paper, we merge the unique properties of cotton and silver in order to obtain antimicrobial cotton fibers. The sorption properties of cotton were improved by selective TEMPO-mediated oxidation, i.e. oxidation with sodium hypochlorite, sodium bromide and 2,2,6,6-tetramethylpiperidine-l-oxyl radical (TEMPO), and evaluated by determination of moisture sorption and water retention. Increases of up to 1.55 and 4.7 times were obtained for moisture sorption and water retention value, respectively. The antimicrobial properties were achieved by incorporation of silver into TEMPO-oxidized cotton by combination of Ag+ chemisorption from aqueous AgNO3 and reduction of Ag+ to Ag-0 by cellulose itself. The amount of incorporated silver was in the range from 0.102 to 0.806 mmol/g fibers. The antimicrobial activity of the obtained fibers against pathogens C. albicans, S. aureus and E. coli was evaluated. An attempt has been made to explain the roles of the introduced functionalities and changes in the sorption properties of the TEMPO-oxidized cotton on silver deposition.