Constructing Superhydrophobicity by Self‐Assembly of SiO₂@Polydopamine Core‐Shell Nanospheres with Robust Oil‐Water Separation Efficiency and Anti‐Corrosion Performance

Abstract

Vulnerable robustness of superhydrophobic materials have mightily hindered their practical applications. Herein, a controllable and effective strategy is demonstrated for constructing robust superhydrophobicity with aqueous hydrophobic interaction driving self-assembly (HIDS), using polydopamine (PDA) as the binder and SiO 2 particles as the nano-sized structures to enable low-adhesive property. The proposed strategy realizes the rapid interfacial assembly of PDA by manipulating the wetting properties of SiO 2 @PDA coreshell particles with hydrophobic modifier. The polyurethane (PU) sponges are facilely rendered superhydrophobic with remarkable robustness, stemming from the excellent adherence of HIDS enhanced covalent interaction between PDA and PU. Coated sponge possesses ultralong-term stability during the oil-water separation, the separation efficiency can be maintained at 98.8% even after 1000 cycle separations and strikingly, superhydrophobicity is still retained after 100 cycle abrasion with ultrahigh loading pressure of 49 kPa. Versatilely, the coatings can be assembled on various substrates through scalable dip coating for attaining superhydrophobicity, regardless of size, roughness, chemistry, and rigidity. The complete water-repellent coatings on permanent magnet of Nd-Fe-B hold excellent anti-corrosion properties without deteriorating the magnetic properties, exhibiting a low corrosion current density of 2.03 × 10 −8 A cm −2 , which is three orders of magnitude lower than that of 1.30 × 10 −5 A cm −2 for bare Nd-Fe-B magnet.

Robust superhydrophobic silicone/epoxy functional coating with excellent chemical stability and self-cleaning ability

“…The peaks at 1071 cm −1 and 1006 cm −1 were attributed to the typical asymmetrical and symmetrical stretching vibrations of Si-O-C and Si-O-Si, implying the formation of silicon backbone structure. 48,49 The additional peak located at 1127 cm −1 was assigned to the stretching vibration of -CF 3 in D3F and AFSR molecules. The 1 H-NMR spectrum of the target supramolecular silicone resin was characterized.…”

Superhydrophobic and photothermal sponge for effective oil/water separation and solar‐assisted recovery of viscous oil

“…Besides, a silver mirror-like phenomenon was observed on the surface of immersed P-CS-PDA@MF sponge (Figure 2e) due to the existence of the air layer trapped on the surface of the superhydrophobic sponge in the water. 38 Figure 2f shows the photos of pure water, beer, milk, and albumin droplets on the surface of P-CS-PDA@MF. All of them were spherical and exhibited good liquid repellency, revealing the superhydrophobic nature of P-CS-PDA@MF.…”

Spontaneous Transport Mechanics of Water Droplets under a Synergistic Action of Designed Pattern and Non-Wetting Gradient

“…Controllable spontaneous water droplet transport has important significance in multiple fields, such as microfluidic devices, − water harvesting, − and water–oil separation. − Surfaces with controlled wetting properties are widely acceptable materials to achieve self-transport of droplets. , In recent years, researchers have modified various surfaces with non-wetting gradient to realize the facility of unidirectional water self-transport. , For instance, Chaudhury and Whitesides experimentally achieved droplet transport on a wetting gradient surface, and a 1 μL droplet moved upward on an inclined surface with a transport velocity of 1–2 mm/s. There are some related literature reporting the steering of droplets using various surfaces.…”

“…Controllable spontaneous water droplet transport has important significance in multiple fields, such as microfluidic devices, 1 − 3 water harvesting, 4 − 6 and water–oil separation. 7 − 9 Surfaces with controlled wetting properties are widely acceptable materials to achieve self-transport of droplets. 10 , 11 In recent years, researchers have modified various surfaces with non-wetting gradient to realize the facility of unidirectional water self-transport.…”