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

Abstract

Superhydrophobicity has been demonstrated on ultrathin rf-sputtered Teflon coated etched aluminum surfaces. The etching of aluminum surfaces has been performed using dilute hydrochloric acid. An optimized etching time of 2.5 min is found to be essential, before Teflon coating, to obtain a highest water contact angle of 164 ± 3° with a lowest contact angle hysteresis of 2.5 ± 1.5°, with the water drops simply rolling off these surfaces with even the slightest inclination of the sample. The presence of − CF3 radicals along with − CF2 radicals in the ultrathin rf-sputtered Teflon films, as investigated by X-ray photoelectron spectroscopy (XPS), contributes to the lowering of the surface energy on the aluminum surfaces. The presence of patterned microstructure as revealed by field emission scanning electron microscope (FESEM) together with the low surface energy ultrathin rf-sputtered Teflon films renders the aluminum surfaces highly superhydrophobic.

Superhydrophobic and icephobic surfaces prepared by RF-sputtered polytetrafluoroethylene coatings

“…There are two main approaches to generate superhydrophobic surfaces: (i) creation of a rough surface from low surface energy materials and (ii) creation of a rough surface followed by a low surface energy material coating step. Many methods have been developed so far to promote surface roughness, including sol-gel, plasma treatment, electrodeposition, anodisation, hot-water immersion, template method, chemical treatment and lithography [13][14][15][16][17][18][19][20]. Anodic aluminum oxide has been proposed as a suitable industrial process for use in the burgeoning field of nanotechnology [21] for developing nano-pore structure films with advantage of improvement of corrosion and wear resistance [22][23][24].…”

Wetting and superhydrophobic properties of PECVD grown hydrocarbon and fluorinated-hydrocarbon coatings

“…The micro-nanoroughness on the Al surfaces were created by chemically etching the Al surfaces using dilute hydrochloric acid (HCl). A detailed procedure aluminum etching by HCl is described in our previous work [15]. The surface chemical compositional analyses were performed by X-ray photoelectron spectroscopy (XPS) (VGESCALAB 220iXL).…”

“…In recent years, our group has been extensively working on the superhydrophobic coatings for its applications in the areas where reduction of ice adhesion is of importance [13], [14], [15], [16], [17], [18] and [19]. The above works are fundamentally based on two step process where initially a rough pattern was created and the rough surface either passivated with fluoroalkylsilane [17] or stearic acid molecules [13], [17], [18] and [19] or coated with rf-sputtered Teflon [15]. Very recently, we have demonstrated that rf-sputtered Teflon coated etched aluminum surfaces are highly superhydrophobic [15].…”

“…The above works are fundamentally based on two step process where initially a rough pattern was created and the rough surface either passivated with fluoroalkylsilane [17] or stearic acid molecules [13], [17], [18] and [19] or coated with rf-sputtered Teflon [15]. Very recently, we have demonstrated that rf-sputtered Teflon coated etched aluminum surfaces are highly superhydrophobic [15]. We have also produced fluorinated-hydrocarbon coatings and demonstrated the formation of fluorinated-hydrocarbon nano-rings using nanosphere lithography (NSL) [16].…”

A facile dip-coating process for preparing highly durable superhydrophobic surface with multi-scale structures on paint films

“…This property is related to the special multi-scale nano/microsurface structures and this correlation is widely known as the lotus effect [6,[11][12][13]. In recent years, many technologies including electrochemical deposition [14][15][16], chemical [17][18][19][20][21][22] and plasma etching [23][24][25], electrospinning [26][27][28], and lithograph [29,30] are utilized to fabricate superhydrophobic surface by mimicking the lotus surface structure.…”