Surface characterization of flat and rough films of perfluoromethacrylate-methylmethacrylate statistical copolymers synthesized in CO2-expanded monomers

Abstract

Statistical copolymers of perfluoroalkyl ethyl methacrylate (Zonyl-TM) and methylmethacrylate were synthesized in CO2-expanded monomer mixture at a low pressure of 10-13 MPa for the first time. M (w) of the copolymers was found to decrease with the increase of Zonyl-TM content. Flat films of these copolymers were obtained by dip coating from their chloroform solutions and were characterized using contact angle measurements, optical microscopy, and 3D profilometry. The increase in the Zonyl-TM content of the copolymers resulted in a decrease of the total surface free energy. Superhydrophobic and oleophobic rough copolymer films were also prepared by applying a phase-separation process where THF was used as the solvent and ethanol as the non-solvent. Surface roughness increased with the increase in the nonsolvent ratio resulting in an increase in the water contact angle from 103A degrees to 151A degrees and hexadecane contact angle from 49A degrees to 73A degrees.