Page 133 - Handbook of Surface Improvement and Modification

128 Easy Surface Cleaning and Stain Inhibition

Figure 8.9. Three-dimensional surface topography of A: neat fabric, B: Tsp-POSS coated fabric, C: FL-POSS
coated fabric (Z scale: 100 nm). [Adapted, by permission, from Misra, R; Cook, RD; Morgan, SE, J. Appl.
Polym. Sci., 115, 2322-31, 2010.]

A stain resistance and cleanability of polished porcelain tiles was improved by seal-
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ing the micro-pores on the tile surface with hybrid sol-gel solution. The hybrid network
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contained tetraalkoxysilane (Si(OR) ) and alkyltrialkoxysilane (RSi(OR) ). The stain
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resistance and the cleanability of the tile surface were tested according to ISO-10545-2014
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standard. The sealing material permanently prevented formation of stains such as olive
oil, green staining paste, and iodine solution on the surface of polished porcelain tiles. 22
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Figure 8.8 shows the model of pore filling by the coating.
Cotton/polyester fabric surfaces were modified using nanostructured organic-inor-
ganic polyhedral oligomeric silsesquioxane (POSS) molecules (a closed cage fluorinated
dodecatrifluoropropyl POSS (FL-POSS) and an open cage nonfluorinated trisilanolphenyl
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POSS) via solution dip coating. Figure 8.9 shows surface morphology of uncoated and
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coated samples. Incorporation of POSS significantly altered the fabric surface topogra-
phy with the appearance of large, raised features (150-200 nm in diameter, up to 100 nm in
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height). POSS-coated fabrics showed complete reversal of surface wetting characteris-
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tics with contact angles higher than polytetrafluoroethylene (Teflon) surface. FL-POSS-
coated fabric has exceptional stain and acid resistance and a 38% reduction in relative sur-
face friction in addition to “nonsliding” and high surface adhesion behavior of water drop-
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lets.
Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized
by two main components: hydrophobic chemical functionalization and surface rough-
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ness. They have water-resistant surfaces but their critical weaknesses are that superhy-
drophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids
under pressure when impacted by a high-velocity stream of water (e.g., rain) and when
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exposed to the physical forces such as abrasion and twisting. The slippery lubricant-
infused porous surfaces, SLIPS, a self-healing, pressure-tolerant, and omniphobic surfaces
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address these issues. Figure 8.10 shows the selection of treatment. SLIPS-functionalized