“Nickel Nanoflowers” with Surface-Attached Fluoropolymer Networks by C,H Insertion for the Generation of Metallic Superhydrophobic Surfaces

Abstract

Metallic superhydrophobic surfaces (SHSs) combine the attractive properties of metals, such as ductility, hardness, and conductivity, with the favorable wetting properties of nanostructured surfaces. Moreover, they promise additional benefits with respect to corrosion protection. For the modification of the intrinsically polar and hydrophilic surfaces of metals, a new method has been developed to deposit a long-term stable, highly hydrophobic coating, using nanostructured Ni surfaces as an example. Such substrates were chosen because the deposition of a thin Ni layer is a common choice for enhancing corrosion resistance of other metals. As the hydrophobic coating, we propose a thin film of an extremely hydrophobic fluoropolymer network. To form this network, a thin layer of a fluoropolymer precursor is deposited on the Ni substrate which includes a comonomer that is capable of C,H insertion cross-linking (CHic). Upon UV irradiation or heating, the cross-linker units become activated and the thin glassy film of the precursor is transformed into a polymer network that coats the surface conformally and permanently, as shown by extensive extraction experiments. To achieve an even higher stability, the same precursor film can also be transformed into a chemically surface-attached network by depositing a self-assembled monolayer of an alkane phosphonic acid on the Ni before coating with the precursor. During cross-linking, by the same chemical process, the growing polymer network will simultaneously attach to the alkane phosphonic acid layer at the surface of the metal. This strategy has been used to turn fractal Ni "nanoflower" surfaces grown by anisotropic electroplating into SHSs. The wetting characteristics of the obtained nanostructured metallic surfaces are studied. Additionally, the corrosion protection effect and the significant mechanical durability are demonstrated.

Protein Repellent, Surface‐Attached Hydrogels Through Spray Coating

“…[ 14,18 ] The network is inherently very stable and strong due to the covalent surface attachment via C,H bonds and these cross‐linked networks have been shown to be stable for many weeks after cross‐linking. [ 1,19 ]…”

“…[14,18] The network is inherently very stable and strong due to the covalent surface attachment via C,H bonds and these cross-linked networks have been shown to be stable for many weeks after cross-linking. [1,19] To apply the hydrogel precursors to a surface, coating techniques such as spin coating, dip coating, and doctor blading are generally preferred. [20][21][22] The downside to these techniques is that they are not optimized or in some cases not even possible to be used for a nonplanar geometry (e.g., containers, tubes, and chambers).…”

Dialectical Observation of Controllable Electrodeposited Ni Nanocones: the Unification of Local Disorder and Overall Order

“…Nanostructured metals with unique surfaces [1] were widely used in a variety of fields, such as surface modification [2], ultra-hydrophobic layers [3][4][5], supercapacitors [6], microelectronic interconnection [7], nanoprobes [8], solar cells [9], gas sensors [10,11], catalysts [12][13][14][15][16][17][18][19], mechanical polishing slurries [20], diamond wheels [21], nanoscale precision surfaces [22,23]. As a result, many preparation techniques of nanostructured metal surfaces had been proposed, including hydrothermal method [10,11], sol-gel method [24], template method [25], chemical vapor deposition method [26], chemical reduction method [27], and microemulsion method [28].…”

“…Furthermore, nickel, as a good ferromagnetic conductive metal, had the advantages of low price, wide use, and excellent corrosion resistance [34]. Ni nanocones obtained by electrodeposition with solution containing NH 4 Cl had important applications in gassensitive sensors [10,11], ultra-hydrophobic surfaces [3][4][5], and catalysts [12][13][14][15][16][17][18][19].…”

Resistance of Superhydrophobic Surface-Functionalized TiO2 Nanotubes to Corrosion and Intense Cavitation

“…In most applications that employ superhydrophobic coatings, a stable Cassie-Baxter state is more desirable than a Wenzel state, because in the Wenzel state the water droplet has a high tendency to adhere to the surface, thereby undermining the self-cleaning, antifouling, and other desirable properties of the materials [ 8 , 9 ]. Therefore, many different techniques have been employed to fabricate rationally designed rough textures on surfaces in order to minimize the liquid–solid contact area fraction parameter and enhance the generation of Cassie-Baxter states [ 10 , 11 , 12 , 13 , 14 ]. As a result, through both experiments and theoretical deductions, a microscale/nanoscale dual or hierarchical structure is considered an ideal texture for a superhydrophobic surface [ 15 , 16 , 17 , 18 , 19 ].…”