Superhydrophobic Perpendicular Nanopin Film by the Bottom-Up Process

Abstract

We first fabricated the superhydrophobic film with a water contact angle of 178 degrees based on a perpendicular nanopin fractal structure by a bottom-up process. Until now, only materials with an original water contact angle larger than 90 degrees , which is classified as hydrophobicity, could be used to fabricate the superhydrophobic film (>170 degrees ) according to the possible fractal structure by a top-down process. Now, in this work, a water contact angle of about 178 degrees can be achieved using a lauric acid-coated film with an original contact angle of 75 degrees , which is classified as hydrophilicity, based on an ideal fractal structure for the superhydrophobic surface which is fabricated by the nanosize pin with 6.5 nm diameter.

Superhydrophobic properties of ultrathin rf-sputtered Teflon films coated etched aluminum surfaces

“…Therefore, the highest contact angle of 164 ± 3° has been obtained on ultrathin rf-sputtered Teflon coated aluminum substrates with the loss of only 7.6% thickness. The contact angle values similar to our observation or even higher have been reported in the recent literatures [22], [23] and [24]. The insets of Fig.…”

Superhydrophobic properties of silver-coated films on copper surface by galvanic exchange reaction

“…5, the water contact angle was about 79 ± 1.1°, implying that the passivated surface is slightly hydrophilic. Although many of the reported superhydrophobic materials are based on the materials with water contact angle greater than 90° in their smooth form, it is not a necessary condition and it is possible to produce superhydrophobic surfaces using slightly hydrophilic materials [35] and [36]. In our experiment, increasing the passivation period or the concentration of SA by more than 2 mM may lead to the formation of patches of SA on the surface, detectable by AFM, which increases its roughness.…”

“…On the other hand, the modified Cassie-Baxter model [32] and [33] predicts the equilibrium contact angle as Equation (3) cos θ′=f(1+cos θ) − where f is the fraction of solid surface area in contact with the water drop and remaining area (1−f) is occupied by air for which the contact angle of water is 180°. With this model, it is possible to obtain θ′ > 90° even if θ < 90°, provided that f is very small, which is achievable by means of fractal structures [34], by a bottom-up approach [35] or even by highly ordered surface by photolithography [13].…”

Effect of SiO2 nanoparticles on the hydrophobic properties of waterborne fluorine-containing epoxy coatings

“…Based on the lotus leaf effect and other natural phenomena [2][3][4][5][6] , highly hydrophobic surfaces have been prepared by roughening low surface energy materials. The chemical composition of a coating determines its surface free energy.…”