Biomimetic superhydrophobic and highly oleophobic cotton textiles

We report a biomimetic procedure to prep. superhydrophobic cotton textiles. By in situ introducing silica particles to cotton fibers to generate a dual-size surface roughness, followed by hydrophobization with polydimethylsiloxane (PDMS), normally hydrophilic cotton has been easily turned superhydrophobic, which exhibits a static water contact angle of 155 Deg for a 10 micro L droplet. The roll-off angle of water droplets depends on the droplet vol., ranging from 7 Deg for a droplet of 50 micro L to 20 Deg for a 7 micro L droplet. When a perfluoroalkyl chain is introduced to the silica particle surface, the superhydrophobic textile also becomes highly oleophobic, as demonstrated by a static contact angle of 140 Deg and a roll-off angle of 24 Deg for a 15 micro L sunflower oil droplet. [on SciFinder (R)]