Ultrasonic-assisted dyeing of silk fibroin nanofibers: an energy-efficient coloration at room temperature

Herein, we report ultrasonic-assisted (UA) dyeing of silk fibroin nanofibers (SFNF) using acid dyes for the very first time. SFNF has been intensively investigated for various textile industries for different applications such as smart wearables, surgical gowns and advanced apparels. UA dyeing at room temperature resulted in enhanced color yield with production time saving up to 60% in comparison to conventional dyeing, which ultimately showed saving of 62.28% electrical and 64.28% thermal energy consumption. SEM images revealed smooth morphology and lesser shrinkage before and after UA dyeing of SFNF. WAXD, wicking and water contact angle showed amorphous behavior and enhanced wettability of UA-dyed SFNF. Chemical changes of dyed SFNF were confirmed using FTIR and XPS. The proposed UA dyeing of SFNF has a great energy-saving potential as well as high production rate, and therefore can be utilized for advanced apparels.