| Concrete is a non-homogeneous,porous,rough surfaced and highly permeable hydrophilic material with micro-crack structure.Most of the durable degradation process of concrete is closely related to the presence of moisture and its migration movement.For example,the long-term contact between concrete material and water in service,the concrete will suffer from chemical erosion,alternating heat and humidity,freeze-thaw cycles,etc.,which will cause drying shrinkage and cracking damage,and the decline or even loss of its performance.However,the road concrete structure in northern China is usually covered with snow and ice in winter.In order to ensure the safety of its structure,the common measure is to spray deicing agent.Unfortunately,the actual application shows that the deicing agent will cause severe freeze-thaw damage to the concrete matrix structure,peeling off the concrete surface and exposing the aggregate,which will result in uneven surface.And these phenomena not only threaten the safety of the matrix structure,but also lead to considerable economic losses due to the increasement of the maintenance cost.Therefore,studying the effects of freezing and thawing on the freezing resistance of concrete is of great significance to prevent the premature durability damage of concrete structure and guide the construction of infrastructure.The existing hydrophobic protection technologies for concrete surfaces all have certain deficiencies.Therefore,it is a simple and effective method to develop a super-hydrophobic anti-icing coating that can be used for ultra-durable protection of concrete surfaces.In view of the key scientific issues above,this paper designed and constructed multi-functional siloxane-containing fluorine-based acrylic copolymer superhydrophobic anti-icing coating with strong bonding ability for the protection of concrete surfaces through sol-gel,self-assembly and nano-dual hybridization methods,which was based on the the concept of molecular structure-effect design.In the design,the presence of silicone groups in the side chain endow the polymer self-crosslinking ability,strong adhesion and great structural stability in harsh environments,which further enhance the mechanical/chemical durability of the composite nano-coating,the specific contents are as follows:Firstly,siloxane-containing fluorine-based acrylic copolymer(FSC)was synthesized via the copolymerization of methyl methacrylate(MMA),3-(trimethoxysilyl)propylmethacrylate(TSMA),stearyl methacrylate(SMA)and2,3,4,5,5,5-hexafluoro-2,4-bis(trifluorinated methyl)pentylmethacrylate(DFMA).FT-IR spectra and 1H-NMR measurement were used to identify the structure,rheological behavior,gel behavior,thermal behavior,media resistance behavior and adhesion behavior were utilized for systematic characterization analysis,the results showed that:the obtained FSC had a good thermal stability,chemical stability,mechanical adhesion and cross-linking properties.Secondly,fluorinated Si O2 nanoparticles(Si O2-F)with different size were synthesized according to the modified St?ber method,using tetraethoxysilane,fluorosilane and water as raw materials,anhydrous ethanol as a solvent,ammonium hydroxide as a catalyst.The chemical structure and composition were analyzed and characterized by infrared spectroscopy spectra(FT-IR),X-ray photoelectron spectroscopy(XPS),and the morphology of Si O2-F were studied by field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM)and dynamic light scattering(DLS).The results showed that Si O2-F with clear structure,uniform particle size distribution(200?320 nm)and storage stability was successfully prepared.Finally,the Si O2-F suspension is mixed with FSC in tetrahydrofuran(THF)solution,and the FSC/Si O2-F nanopolymer composite dispersion was prepared by ultrasound,and then sprayed to the surfaces of concrete,ceramics,glass,paper,tinplate and wood,forming a stable coating through thermal treatment.The surface morphology and roughness of the coating were analyzed and characterized by FE-SEM,atomic force microscope(AFM),etc.The comprehensive evaluation of the wettability,stain resistance,mechanical durability,chemical stability,weather resistance and anti-icing performance of the FSC/Si O2-F nano-polymer coatings were conducted by the measurement of water contact angle(WCA)and sliding angle(SA).The results showed that the coatings had excellent super-hydrophobicity and self-cleaning ability,mechanical and chemical durability,anti-icing performance,freezing resistance and weather resistance.In summary,the prepared FSC can be used as the reaction template to construct super-hydrophobic polymer coatings with micro-nano hierarchical structure,which can be widely used in the field of anti-icing durability protection of concrete,metal,ceramics,etc.Therefore,it has important theoretical and application guidance value to guide the anti-icing durability of concrete engineering structures. |
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