Fabrication of robust and repairable superhydrophobic coatings by an immersion method
Introduction
Since the discovery of lotus effect, superhydrophobic surfaces with static water contact angle more than 150° and sliding angle less than 10° have shown distinguished performance in different potential application fields, such as self-cleaning, oil-water separation, anti-condensation, anti-frosting, anti-icing and anti-corrosion [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14]. As we know, the formation of superhydrophobicity is attributed to highly textured structures and low surface energy. However, the superhydrophobic property and surface robustness are inherent contradictions because with the increase of roughness, the hydrophobicity enhances while the surface becomes more vulnerable [15], [16], [17], [18], [19].
Techniques used to solve the robustness and durability issues mainly include adjusting the coarse structure, strengthening the bonding between superhydrophobic coatings and substrates and making the surface self-healing. Originally, it is demonstrated that microscale bumps can provide protection to nanoscale roughness, which is too fragile to resist destruction, so the micro/nano hierarchical structure is essential to enhance the wear resistance [20], [21], [22]. With the further research, it is found that this composite structure is still vulnerable and the coating is far from meeting the requirement of robustness. During the past few years, adhesives have been widely used to splice the films and substrates to prevent the rough structure from being polished with external force [23], [24], [25], [26], [27], [28]. Although this method has good effect on improving robustness, it usually takes two steps to complete the preparation and needs complex techniques. Also, the coating is customarily painted by brushing or spraying method, which cannot be applied to inner wall or other complicated parts’ surfaces, unlike immersion or dipping method [29], [30]. In addition, to imitate lotus leaves, which have the ability to regenerate epicuticular wax to maintain the surface low energy after damage or contamination, self-repairable surfaces have been created successfully in two dimensions, keeping the existence of rough structures or ensuring the continuous supply of low energy substances [31], [32], [33], [34].
As inspired by the above works, we fabricated a novel mechanically robust superhydrophobic surface with repairing ability through straightforward immersion method. A kind of hydrophobic resin, which has strong bonding with substrate and can fully cure at room temperature, and superhydrophobic nanoscale silica particles were major components of the coating and the particle content and immersion time were discussed seriously to ensure achieving optimized performances. Sandpaper abrasion and sand/water impact tests all demonstrated that the coating could withstand a considerable degree of external force destruction. What’s more, this coating was able to return to superhydrophobic state via immersed again after suffering mechanical damage, which mainly because of the recovery of micro/nano hierarchical structure. In practical, the obtained superhydrophobic coating is applicable to a modest environment and it is believed that it can be prepared in large scale application, even on the inner surfaces of complex structural parts.
Section snippets
Materials
Fluoroethylene vinyl ether (FEVE) and curing agent were purchased from Suzhou CY-CH Co., Ltd. Silica nanoparticles with the size of 10–20 nm were obtained from Evonik Degussa China Co., Ltd. 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDTES) were provided by Sikang New Material Co., Ltd. Absolute ethyl alcohol (EtOH), acetone, ammonium hydroxide (28%), deionized water, tetraethyl orthosilicate (TEOS), butyl acetate, hydrochloric acid (HCl) and sodium hydroxide (NaOH) were purchased from
Effects of particle content and immersion time on wettability
Fig. 1 shows the sketchy procedure to fabricate superhydrophobic coating via two-step immersion method. First, superhydrophobic silica nanoparticles and FEVE resin, a kind of fluorocarbon hydrophobic resin, are added to butyl acetate. Resin and particles dispersed evenly in the diluent by magnetic agitation for about 15 min. Then, the glass substrate was immersed into the solution for 5 min. At this first-immersion process, the coating was painted firmly because of the cohesive action between
Conclusions
In conclusion, a new kind of superhydrophobic surface has been developed via extremely simple two step immersion method with fluorocarbon resin and silica particles. The immersion time and particle content have both been discussed and the contact and sliding angles of the surface are 159.5° and 1.0°, respectively, with 30 min second-immersion time and 25% nanoparticle content. Through abrasion and impact tests, the robustness of superhydrophobicity is systematically demonstrated. It is worth
Notes
The authors declare no competing financial interest.
Acknowledgments
This work was financially supported by the National Natural Science Foundation of China (Grants 51671055, 51676033), the China National Key R&D Program (2016YFC0700304).
References (34)
- et al.
Condensation and freezing of droplets on superhydrophobic surfaces
Adv. Colloid Interfac.
(2014) - et al.
Superhydrophobic surfaces with excellent mechanical durability and easy repairability
Appl. Surf. Sci.
(2013) - et al.
Facile fabrication of translucent superamphiphobic coating on paper to prevent liquid pollution
Chem. Eng. J.
(2014) - et al.
Facile spray-coating process for the fabrication of tunable adhesive superhydrophobic surfaces with heterogeneous chemical compositions used for selective transportation of microdroplets with different volumes
ACS Appl. Mater. Inter.
(2014) - et al.
One-step approach to durable and robust superhydrophobic textiles
Adv. Funct. Mater.
(2008) - et al.
Robust and superhydrophobic surface modification by a “paint plus adhesive” method: applications in self-cleaning after oil contamination and oil water separation
ACS Appl. Mater. Inter.
(2016) - et al.
Large-scale fabrication of translucent and repairable superhydrophobic spray coatings with remarkable mechanical, chemical durability and UV resistance
J. Mater. Chem. A
(2017) - et al.
A superhydrophobic copper mesh as an advanced platform for oil-water separation
Appl. Surf. Sci.
(2018) - et al.
Movement and regeneration of epicuticular waxes through plant cuticles
Planta
(2001) - et al.
A facile and large-area fabrication method of superhydrophobic self-cleaning fluorinated polysiloxane/TiO2 nanocomposite coatings with long-term durability
J. Mater. Chem.
(2011)
Large-scale fabrication of translucent, stretchable and durable superhydrophobic composite films
J. Mater. Chem. A
Nature-inspired strategy toward superhydrophobic fabrics for versatile oil/water separation
ACS Appl. Mater. Inter.
A facile immersion-curing approach to surface-tailored poly(vinyl alcohol)/silica underwater superoleophobic coatings with improved transparency and robustness
J. Mater. Chem. A
The dry-style antifogging properties of mosquito compound eyes and artificial analogues prepared by soft lithography
Adv. Mater.
Meltwater evolution during defrosting on superhydrophobic surfaces
ACS Appl. Mater. Inter.
Low ice adhesion on nano-textured superhydrophobic surfaces under supersaturated conditions
ACS Appl. Mater. Inter.
Superhydrophobicity vs. ice adhesion: the quandary of robust icephobic surface design
Adv. Mater. Interfaces
Reinforced superhydrophobic coating on silicone rubber for longstanding anti-icing performance in severe conditions
ACS Appl. Mater. Inter.
Cited by (99)
Preparation and properties of high abrasion resistant superhydrophobic coating on the PCB
2024, Colloids and Surfaces A: Physicochemical and Engineering AspectsMechanical stability of one-step electrodeposited Ni-graphene superhydrophobic coating
2024, Colloids and Surfaces A: Physicochemical and Engineering AspectsEndowing durable icephobicity by combination of a rough powder coating and a superamphiphobic coating
2024, Chemical Engineering Journal