Photophysical and surface characteristics of electrospun polysulfone/nickel fibers

Wettability behavior of solution blow spun polysulfone by controlling morphology

“…Several works showed how polysulfone surfaces can condition the contact angle formed between a water drop and the polymer surface. For instance, E. Bormashenko et al showed that the contact angle of water on a flat smooth surface of extruded PSf is 79°, 58 on the other hand, PSf based materials made of electrospun fibers with average diameter of about 800 nm presented a water contact angle of 103.8° 59 . These results agree the well known influence of surface morphology on the contact angle of a liquid.…”

“…In other words, if a surface is chemically hydrophobic it will behave even more hydrophobic if its roughness increases and vice versa. In fact, J. Teno obtained even higher water contact angles than those obtained in references 58,59 in more complex PSf surfaces obtained by SBS using a commercial airbrush, 107° 23 …”

“…In the Wenzel's model, there is a relation between the real contact angle formed on the rough surface, θ W , and the contact angle formed on a perfectly smooth surface, θ where r is the so called roughness factor 60 . Taking into account a value of about 80° for the water contact angle when the water drop is deposited on a smooth surface of PSf 58,59 and the roughness measurements for the samples under study, an estimation of the real contact angle could be done. In Table 6 the arithmetical mean roughness, R a , and the roughness factor, r , of the three samples chosen are gathered.…”

“…In the Cassie‐Baxter approximation, 61 the relation between the real contact angle formed on the rough surface, θ CB , and the contact angle formed on the smooth surface, θ, is given by where φ S is the fraction of solid surface in direct contact with the liquid. Taking into account a value of about 80° for the water contact angle when the water drop is deposited on a perfectly smooth surface 58,59 and the experimental value of the contact angle on the rough surfaces, the fraction of solid surface in contact with the liquid, φ S , could be estimated from Equation ). Then, with this estimated fraction, φ S, for a particular microscopic region of observation, knowing the distribution of fibers sizes in terms of their diameters and the relative amount of fibers in terms of RoF, it would be possible to make an estimation of the number of fibers and beads or solid material in form of fibers and beads that will be in contact with a water drop.…”