Sterilization of microorganisms in silk fabrics by microwave-induced argon plasma treatment at atmospheric pressure

Since many old cultural assets, such as clothes, pictures and books, remain in the state of silk fabrics or papers, it is very difficult as well as important to retain their original form. Microbial contamination induces surface deformations and strength degradation of silk fabrics by invading deeply into the fibers. In this study, the sterilization effects of microwave-induced argon plasma at atmospheric pressure were investigated on the microorganisms in silk fabrics. Also, the influence of the plasma treatment was examined on the physical properties of the fabrics. Argon plasma treatment completely sterilized the silk fabrics inoculated with various strains of either bacteria or fungi. It was also found that the plasma treatment did not affect the ultimate tensile strength and surface morphology of the fabrics because it took advantage of relatively low temperature. As increase in the plasma treatment, however, the lightness of silk fabrics decreased with concomitant increased in the color intensities of green and yellow. These results suggest that microwave-induced argon plasma can be effectively used as an alternative method for sterilizing and protecting cultural assets out of silk fabrics without any deterioration of the tensile strength and surface morphology. (c) 2008 Elsevier B.V. All rights reserved.