Study on the influence of micro-nanostructures on the performance of PTFE superhydrophobic coatings on cement concrete
In order to investigate the influence of micro-nano rough structures on the performance of polytet-rafluoroethylene(PTFE)superhydrophobic coatings on cement concrete-based substrates,this study considered the rough structures on the concrete surface and the micro-nano rough structures constructed using micrometer-level diamond,silicon carbide,alumina powder,and nanometer-level hydrophobic silica powder.Contact angle measurements and scanning electron microscopy(SEM)were used to characterize the wettability and micro-structure of PTFE coatings on various rough structures.Additionally,the slip resistance and wear resistance of the coatings were evaluated.The results showed that a two-step fabrication process,involving the construction of micro-nano rough structures followed by PTFE coating modification,achieved the highest superhydrophobic performance.The best results were obtained when micrometer-level and nanometer-level powders were com-bined,with the performance improving as the dosage increased,with a recommended ratio of 1:1 and a particle size ratio controlled within the range of 60-120 times.Among different rough structures,diamond showed the best performance,followed by silicon carbide and corundum.After concrete surface treatment with chiseling,all the coatings met the requirements for slip resistance,and after 1000 cycles of reciprocal friction on the test surface using a wet wheel abrasion tester,the superhydrophobicity remained above 85%.This study provides insights into the mechanisms by which micro-nano rough structures affect coating performance and can guide the preparation of practical,high-performance PTFE superhydrophobic coatings.