Page 110 - Handbook of Surface Improvement and Modification

7.1 Methods and mechanisms of surface tension change 105

addition of compatibilizer reduced the size of dispersed liquid crystalline polymer and
17
improved its dispersion in the matrix promoting its fibrillation.
The influences of surface wettability and interfacial energy on the coefficient of fric-
18
tion were investigated. Both the interfacial energy and wettability of tribopair surfaces
18
characterized the lubrication processes.
Surface wettability of conducting polymers can be tuned by incorporation of hydro-
phobic/hydrophilic doping ions, changing the nature of the polymerizable core or by func-
19
tionalization with various hydrophobic/hydrophilic substituents. The electrochemical
polymerization on conductive substrates or the vapor-phase polymerization provide an
easy control of the surface morphology at micro- or a nano-scale with a surface wettability
19
going from superhydrophilicity to superoleophobicity. Using composite microspheres
(polystyrene microspheres were used as seed (hard template) for the growth of polyaniline
nanofibers), superhydrophobic surfaces with dual-responsive wettability were obtained
20
(Figure 7.9). The surfaces with switchable wettability from superhydrophobic to super-
20
hydrophilic were elaborated by changing either the electrical potential or the pH. Many

Figure 7.10. SEM images of (a) neat TPU top substrate surface; (b) silica, SP-TPU top substrate surface; (c) SP-
TPU cross-section surface obtained by cryogenic fracture; (d) detail of (c) and (e) top surface of the SP-TPU sub-
strate SP without thermal treatment. [Adapted, by permission, from Cruz, S; Rocha, LA; Viana, JC, Appl. Surf.
Sci., 360, 198-206, 2016.]