Method for preparing super-hydrophobic surface with ultra-critical CO2 rapid expansion method

Abstract

The invention discloses a method for preparing a super-hydrophobic surface with an ultra-critical CO2 rapid expansion method. The method comprises the following steps of: activating nano-silica with hydrochloric acid, filtering, drying, adding absolute ethanol, adding distilled water, adding two kinds of coupling agents containing fluorine and double bonds, washing a product, filtering and dryingto obtain nano-silica particles containing double bonds; adding the nano-silica particles containing double bonds into an ultra-critical CO2 reaction kettle, stirring, and spraying onto a water-basedpolyurethane paint surface which is end-capped with double bonds and is added with an initiator; and drying, grafting the nano-silica particles onto a polyurethane coating surface to form a stable structure to obtain a super-hydrophobic surface. A process used in the method is environmentally-friendly, the ultra-critical CO2 is a nontoxic, non-flammable and environmentally-friendly solvent, the solvent which quickly expands in a fluid and solute particles are easy to separate rapidly and completely, and no solvent is left in the particles; and the preparation efficiency is high, the method issuitable for large-area preparation, and high film coating stability and high scratch resistance are achieved.

Description

[0001] technical field [0002] The invention relates to a superhydrophobic surface, specifically a supercritical CO 2 Preparation by rapid expansion method [0003] approach to superhydrophobic surfaces. Background technique [0004] Superhydrophobic coating is a new type of coating with special surface properties. Its surface refers to a solid coating with a water contact angle θ greater than 150° and a water contact angle hysteresis generally less than 5°. It has superhydrophobic properties like lotus leaves , water drops are easy to slide on it without sticking, and have important characteristics such as waterproof, anti-fog, anti-snow, anti-pollution, anti-adhesion, anti-oxidation, anti-corrosion, self-cleaning, and prevention of current conduction. It is widely used in scientific research, production, and life. There are extremely broad application prospects in many fields. Superhydrophobic technology is also of great practical significance for anti-corrosion, anti-...

AI Technical Summary

Problems solved by technology

[0005] At present, there are many methods for preparing superhydrophobic surfaces, such as: femtosecond laser etching method, phase separation method, self-assembly method, hydrothermal method, chemical deposition and electrodeposition method, sol-gel method, electrospinning method , template method, etc. However, the current various technologies are still difficult to solve the preparation of large-area super-hydrophobic surfaces and coatings, many of which are only prepared in a small area in the laboratory and are only used for experimental research.

Many technologies still have problems such as the need to use complex equipment or high-temperature treatment, such as patent 200910098056.4, using CaCO 3 The particle template method is used to process polyethylene or polypropylene, and its hot-pressing temperature reaches 160-250 ° C, and it cannot be produced on a large scale; some use organic solvents, which is not conducive to environmental protection, such as patent 201010157986. N, N-dimethylformamide and other organic solvents are obtained from methyl acetamide, and the proportion of solvent added is as high as: 86.5-99.3%; other methods are complicated in process and high in cost, which limits the type and quantity of superhydrophobic surface or coating products. For example, the patent 200910088646.9 uses high-temperature plasma spraying technology to prepare super-hydrophobic surfaces, which requires high temperature, high pressure, and high current conditions, and can only be sprayed on metal surfaces, which greatly limits its application range

In addition, the stability and durability of the super-hydrophobic surface prepared by these methods, especially the scratch resistance and hydraulic shock resistance, need to be improved, such as patent 200910098056.4, the super-hydrophobic surface has many sunken holes, and the dust is not easy to remove after entering, and The material is polyethylene or polypropylene, which has poor scratch resistance and eventually loses its superhydrophobic effect