Robust Technique Allowing the Manufacture of Superoleophobic (Omniphobic) Metallic Surfaces

Abstract

Omniphobic metallic surfaces obtained with a robust two-stage process are reported. The surfaces demonstrate high apparent contact angles accompanied with a low contact angle hysteresis for a variety of liquids, including water, diidomethane, canola, castor, silicone oils, and crude petroleum oil. The superoleophobicity was achieved by fluorination of the nano-rough aluminum surfaces under treatment with perfluorononanoic acid, as established by TOF-SIMS spectrometry. The stability of the Cassie wetting regime was investigated. The critical surface tension of a liquid corresponding to the onset of wetting transitions was established experimentally.

Drop-wise and film-wise water condensation processes occurring on metallic micro-scaled surfaces

“…The surface after modification acquired SH properties demonstrating the water apparent contact angle 0 * 1 152   (see Figure 2A) and low contact angle hysteresis studied in detail in Ref. 25.…”

“…The samples were dried during 10 min at 100°C after the etching stage (Section 2.1). Dried micro- were registered [25,35]. The apparent contact angles were measured by a Ramee-Hart Advanced Goniometer Model 500-F1 under ambient conditions.…”

“…Our paper is focused on water condensation on micro-scaled aluminum surfaces, which is of particular interest for preventing corrosion [24]. Aluminum is inherently a hydrophilic material, however, manufacturing of appropriate surface reliefs may convert aluminum surfaces into hydrophobic and even superhydrophobic ones [25].…”

“…It is reasonable to relate the observed difference in the processes of condensation to various stability of the Cassie wetting state [37-41, 45], inherent for the studied SH and SO surfaces. The stability of the Cassie wetting regime was estimated by the establishment of the critical surface tension of a droplet c  , corresponding to the onset of the Cassie-Wenzel transition (see Section 2.3 and Refs 19,25)…”

The springtail cuticle as a blueprint for omniphobic surfaces

“…85,88,89 In addition, several experimental studies support the geometrical concept of re-entrant structures or surface features exhibiting overhangs, and numerous rough surfaces such as porous metal surfaces, 86,90,91 certain polymers 92,93 or oxide-based 68,94 structures, fiber mats and fabrics, 95,96 pillar structures, 56,[97][98][99] or hierarchical structures 100 could be engineered and characterized. 85,88,89 In addition, several experimental studies support the geometrical concept of re-entrant structures or surface features exhibiting overhangs, and numerous rough surfaces such as porous metal surfaces, 86,90,91 certain polymers 92,93 or oxide-based 68,94 structures, fiber mats and fabrics, 95,96 pillar structures, 56,[97][98][99] or hierarchical structures 100 could be engineered and characterized.…”