Antibacterial finishing of cotton with silk hydrogel and chamomile extract

In this research, silk as a source of protein fibroin, with very good mechanical properties, has been used to prepare hydrogels. For this purpose, 20% fibroin was dissolved in water and calcium chloride was added to accelerate the gelation process. The pH of the liquid was adjusted to 4 with HCl. Then, the solution was sonicated using an ultrasonic apparatus for 3 minutes. Finally, 5% chamomile extract was added to the hydrogel under ultrasonic condition and applied on cotton fabrics. The morphology, chemical structure, and swelling of the specimens, the release rate of the extract and antibacterial properties of the hydrogel were evaluated. SEM images showed the proper coating of cotton with silk hydrogel. FTIR spectra confirmed the presence of functional groups in the hydrogel and chamomile extract. The results of swelling showed that the incorporation of hydrogel increased the water absorption of fabrics and there was a slight reduction in water absorption after loading the extract in the hydrogel. Besides, the antibacterial test confirmed the antibacterial properties of the hydrogel against both gram-positive and gram-negative bacteria