Contact angle measurement
Contact angle is an important parameter in surface sciences,
which represents the surface hydrophilicity. Smaller contact angle
indicates better hydrophilic performance. Table 2 summarizes the contact angle values of oil waste water with oil concentration of
300 mg/L on PVDF and PVDF–PVP membranes. Comparing the
listed contact angle values, the PVDF–PVP membranes were more
hydrophilic than the original PVP membranes owing to the introduction
of PVP during modification.