PFDTS nanostructures

Abstract The self-assembled formation of PFDTS features on mono- and multilayered silica sphere arrays is studied. The multiscaled roughness induced by PFDTS nanostructures on multilayer arrays gives rise to superhydrophobic behaviour. In contrast to previous work, the role of PFDTS is two-fold it lowers the surface energy and simultaneously provides the essential roughness to achieve superhydrophobicity. The importance of water in the formation of the nanostructured surfaces is discussed. 

To verily the important role of water in the PFDTS self-assembly, we performed a control experiment under controlled, water-free conditions in a glove box, using a solution prepared with anhydrous solvent. Results reveal that in the absence of sufficient water, the PFDTS nanostructures are not formed. 

Table 1 Water contact angles (CA) and sliding angle (SA) on PFDTS-treated mono- and multilayer arrays for different silica sphere diameters. Also, the surface coverages of PFDTS nanostructures are given...

In the present work we show that under specific experimental conditions, the adsorption of PFDTS on silica sphere arrays leads to the self-assembled formation of nanostructures. Therewith the role of the fluoroalkylsilane polymer becomes two-fold (i) it simultaneously reduces the surface energy and (ii) leads to an increase of the surface roughness. As far as we are aware, such a double role for PFDTS has not been observed previously. 

We investigated the effect of PFDTS treatment on monolayer and multilayer arrays of silica microspheres with varying diameters. Details pertaining to the preparation methods and experimental conditions are available elsewhere [15]. In Figure 1 the formation of a homogeneous layer on silica sphere monolayers and the formation of nanostructures on... 

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