Figure 6. AFM (2D and3D) images of the surface roughness of the
PTFE membrane (a, b) and PES membrane (c, d).
The solution hydrophilicity is another property impacting the
interfacial nucleation. As shown in Figure 7, PTEF and PES membrane
surface had diverse surface contract properties with the thiourea
aqueous solution. The contact angle of the PTFE hollow fiber membrane is
around 108°, and the contact angle of the PES hollow fiber membrane is
around 83°. The increasing concentration of thiourea (from 3 wt% to 12
wt%) had almost no influence on the contact angle, which ensure a
stable nucleation control performance under wide feed solution
concentration.