Polystyrene graft modification of cotton fibers by ATRP in situ surface roughening and superhydrophobic fabrics

In this paper, 2-bromoisobutyryl bromide (BIBB) was used to gain access to the active site of an atom transfer radical polymerization (ATRP) reaction on fiber surface to prepare a Cotton-Br macromolecular initiator. It was then used to trigger the ATRP polymerization of styrene under the PMDETA/CuBr system. The influence of monomer concentration, bath ratio, and grafting time on the in situ generation of micro- and nanomorphic coatings on fiber surfaces were also investigated. Cotton-PS, a cotton fabric with controllable rough morphology of fiber surface, was obtained through the adjustment of grafting reaction conditions. Energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and atomic force microscope (AFM) test proved that grafting reaction was successful. The C–Br on coating surface can condensed with perfluoropolyether carboxylic acid (PFPE-COOH), and the ensuing reaction introduces Diazabicycloundecene (DBU), thereby activating the PFPE-COOH. Under mild reaction conditions, this process produces superhydrophobic cotton fabrics. The effect of different molecular weight PFPE-COOHs on hydrophobicity was also investigated during chemical modification. The contact angle (CA) of modified cotton fabric increased from 144.8 ± 3.6° to 155.2 ± 3.5° after chemical modification with PFPE-COOH, exhibiting superhydrophobicity. The finished fabric showed excellent oil-water separation performance. Subsequent to the completion of 10 cycle tests, its oil-water separation efficiency was maintained at 98.6 %.