Superhydrophobic perfluoropolymer surfaces having heterogeneous roughness created by dip-coating from solutions containing a nonsolvent

作者：Cengiz Ugur^*; Erbil H Yildirim

来源：Applied Surface Science, 2014, 292: 591-597.

DOI：10.1016/j.apsusc.2013.12.013

• Superhydrophobic
• Oleophobic
• Hierarchical
• Perfluoroacrylate
• Phase separation

Superhydrophobic and oleophobic rough copolymer surfaces containing micro- and nano-hierarchical ball-like islands having diameters between 100 nm and 7 mu m were formed using styrene-perfluoromethacrylate random copolymers which were dip-coated on glass slides from THF and MEK mixture containing methanol as nonsolvent. These copolymers were synthesized in a CO2-expanded monomer medium at 250 bar pressure and 80 degrees C. The sizes of the micro-islands can be controlled by varying the copolymer composition; and the degree of phase separation by adjusting the solvent/non-solvent ratio. Flat and lotus-like hierarchical surfaces of the copolymers were characterized using contact angle measurements and SEM. The increase in the perfluoromethacrylate content of the flat copolymers resulted in a decrease of the total surface free energy of the flat copolymer surfaces from 18.3 down to 14.2 mJ/m(2). The increase in the methanol non-solvent fraction resulted in decrease of the micro-island diameter from 7 mu m down to 100 nm and the water contact angle increased from 117 degrees up to 160 degrees and hexadecane from 65 degrees up to 90 degrees.

• 出版日期2014-2-15