Preparation of polydimethylsiloxane superhydrophobic coatings with self-healing properties by a template method
The main factors hindering the applicability of superhydrophobic coatings are the complexity of their preparation method, high cost, and poor mechanical stability. In order to solve these problems, we prepared polydimethylsiloxane (PDMS) coatings with good mechanical stability by combining sodium chloride particle templates with flame treatment technology. The coating exhibited good superhydrophobicity due to the micro/nanostructures on the surface of the coating with a maximum water contact angle of 163° and a water sliding angle of less than 2°. Good mechanical stability was demonstrated by tape stripping and sandpaper grinding tests. We also observed that the damaged PDMS coating recovered its superhydrophobicity due to the partial decomposition of the polymer. The results show that a low-cost and simple method can be used to prepare high-quality PDMS superhydrophobic coatings that are resistant to
There are three main strategies to improve the wear resistance of superhydrophobic coatings: the use of self-healing materials, the addition of complementary compounds, and the construction of layered micro/nanostructured surfaces. The self-healing material can restore the superhydrophobicity of a damaged coating by reconstructing the micro/nanostructured surface or by rapidly replenishing the coating surface with low surface energy components. The quality of the repair process may depend on specific conditions. Moreover, due to the limited repair efficiency and performance, the preparation of self-healing materials needs to be further explored and improved. However, the introduction of auxiliary reagents and the construction of layered
micro/nanostructured surfaces could be more effective.
Preparation process of superhydrophobic PDMS coatings
The auxiliary reagents, generally silane coupling agents or resin binders, can consolidate the structure of the nanoparticles, improve the adhesion between the substrate and the superhydrophobic material, and increase the scratch resistance of the coating. The rough and high-strength micro/nanoscale layered structure obtained on the substrate effectively protects the hydrophobic nanoparticles from external abrasion. However, there are technical bottlenecks in the design and preparation of complex microstructures. In addition, substrates are often damaged during these syntheses. Polydimethylsiloxanes (PDMS) have excellent processability, thermal and mechanical properties, and low surface energy. Superhydrophobicity can only be achieved by preparing a rough structure on the surface. In general, template methods can replicate the template micro/nanostructure on the PDMS surface. The template method, as a microfabrication technique, has been well developed in the last decade because the shape and structure of the template can be easily replicated. Superhydrophobic surfaces with micro/nanostructures have been prepared using natural templates. However, it is worth noting that natural templates have a limiting template size and cannot be prepared on a large scale. Therefore, it is important to develop a simple and effective template method.
Our study focuses on a low-cost and simple method to prepare PDMS superhydrophobic coatings with micro/nanolayered structures using sodium chloride particles as templates and flame treatment. The coating not only has good mechanical stability and self-healing properties, but also has high self-cleaning properties and anti-icing properties. The method is simple, environmentally friendly and has good applicability.
