Synthesis of versatile fluorinated polysiloxanes and applications on cotton fabrics for durable liquid repellency and color deepening

Fluorinated compounds with side-chains longer than six carbon have been banned due to their toxicity to environment, organisms and human, so that attentions have been paid on degradable short-chain fluorinated or non-fluorinated materials. Here in this paper, several novel short-chain fluorinated polysiloxanes with multi-functions were synthesized successfully and applied on cotton fabrics. Chemical structure of these fluorinated polysiloxanes were characterized by Fourier-transform infrared spectrum and nuclear magnetic resonance. Liquid repellency, washing durability, thermal stability, fabric style and color deepening of treated cotton fabrics were investigated. Additionally, the effect of benzoyl spacer on the surface wettability was fully studied. Results demonstrate that FPAPS-20@cotton (cotton fabric treated by fluorinated polysiloxane with 20% fluorine content) exhibits the greatest liquid repellency as the contact angles for water, ethylene glycol, glycerol and octane are 150.1°, 132.3°, 138.1° and 105.5°. Moreover, the benzoyl spacer plays a positive role in the durable wettability of FPAPS-20@cotton, resulting in the water contact angles ranging from 150.1° to 146.0° when FPAPS-20@cotton exposes to the water droplet for 20 min. X-ray photoelectron spectroscopy provides the experimental evidence for this result. On the other hand, thermal-gravimetric analysis confirms that the fluoroalkyl segments of the fluorinated polysiloxanes can decelerate the thermal decomposition of cotton fabrics. Moreover, compared with the untreated dyed cotton fabric, the K/S values of cotton fabrics with navy, red and orange color treated with FPAPS-20 increase by 42.61%, 11.00% and 18.18%, respectively.