Hydrophilic/oleophobic surfaces are desirable in many
applications
including self-cleaning, antifogging, oil–water separation,
etc. However, making plastic surfaces hydrophilic/oleophobic is challenging
due to the intrinsic hydrophobicity/oleophilicity of plastics. Here,
we report a simple and effective method of making plastics hydrophilic/oleophobic.
Plastics, including poly (methyl methacrylate) (PMMA), polystyrene
(PS), and polycarbonate (PC), have been coated with a perfluoropolyether
(PFPE) (i.e., commercially known as Zdol) via dip coating and then
irradiated with UV/Ozone. The contact angle measurements indicate
that the treated plastics have a lower water contact angle (WCA) and
higher hexadecane contact angle (HCA), i.e., they are simultaneously
hydrophilic/oleophobic. The Fourier transform infrared (FTIR) results
suggest that UV/Ozone treatment introduces oxygen-containing polar
groups on the plastic surfaces, which renders the plastic surfaces
hydrophilic. Meanwhile, more orderly packed PFPE Zdol molecules, which
is due to the UV-induced bonding between PFPE Zdol and the plastic
surface, result in the oleophobicity. Moreover, the simultaneous hydrophilicity/oleophobicity
of functionalized plastics does not degrade in aging tests, and they
have superior antifogging performance and detergent-free cleaning
capability. This simple method developed here potentially can be applied
to other plastics and has important implications in the functionalization
of plastic surfaces.