Page 134 - Handbook of Surface Improvement and Modification

8.1 Methods and mechanisms of surface cleaning 129

Figure 8.10. Design principles of lubricated nanostructured fabrics (SLIPS-fabrics). A single, bare fiber being
functionalized with SLIPS is depicted in a schematic (A)-(D). A bare fiber (A) is roughened with the silica-
microparticle (SiM) or sol-gel boehmite (SgB) approach (B) and fluorinated to achieve chemical similarity to a
perfluoropolyether-based lubricant (e.g., Krytox) (C) before the lubricating film is applied (D). This confers pres-
sure-tolerant, self-healing repellency against a broad range of fluids. The flow chart (E) contains more specific
information regarding the SiM and SgB functionalization protocols applied to cotton and polyester fabrics. Note
that APTES is (3-aminopropyl)triethoxysilane. [Adapted, by permission, from Shillingford, C; MacCallum, N;
Wong, T-S; Kim, P; Aizenberg, J, Nanotechnology, 25, 014019, 2014.]

Figure 8.11. Scanning electron microscope (SEM) characterization of fabric treatments. SEM was used to evalu-
ate the surface roughness and durability of the sol-gel boehmite (SgB) ((A)–(D)) and silica-microparticle (SiM)
((E)–(H)) treatments on Nike polyester fabric. All scale bars are 2 μm. Freshly treated SgB fibers (A) show full
coverage of the fiber with SgB; dramatic microbead coverage is apparent on freshly treated SiM fibers (E). High
magnification of the microstructures ((B), (F)) reveals the surface roughness that facilitates good SLIPS perfor-
mance. When twisted 50 times, smoother boehmite is still present (C) in crevices between fibers, while the
outsides of the fibers have become smooth. Also after 50 twists, the SiM threads (G) exhibit some cracking while
maintaining good microparticle coverage. After vigorous rubbing with a Kimwipe, SgB fabric (D) exhibits
cracking and smoothness on the outer fibers, while under the same conditions the SiM coating remains intact (H).
[Adapted, by permission, from Shillingford, C; MacCallum, N; Wong, T-S; Kim, P; Aizenberg, J, Nanotechnol-
ogy, 25, 014019, 2014.]
cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles,
omni-repellent properties against various fluids including polar and nonpolar liquids, pres-