管道内多巴胺超疏水涂层的制备

Preparation of dopamine super-hydrophobic coating in pipeline

超疏水涂层在表面自清洁、流体减阻、防雾防冰冻和微流控等领域具有巨大的应用潜力,而工程应用中圆管内表面超疏水涂层微结构的调控具有一定的挑战性。利用电化学沉积法,在不同的剪切应力下将聚多巴胺(PDA)涂层制备到不锈钢圆筒内壁,并将正十二硫醇(NDM)修饰到PDA表面,进而制备出PDA/NDM超疏水涂层。采用场发射扫描电镜(SEM)、接触角测试仪(CA)、傅里叶变换红外光谱(FT-IR)、X射线衍射测试仪(XRD)进行分析和表征。结果表明PDA沉积过程可分为两个阶段,第一阶段为溶液中的PDA颗粒在不锈钢基底上面团聚;第二阶段以PDA颗粒团聚体为基础,PDA进行原位生长,并且生长过程受到剪切应力的控制。不同剪切应力最终生长的形貌有所不同,当剪切应力为1.85 mPa时,涂层表面呈“珊瑚状”小球,粒径大小约15~24μm;而当剪切应力为7.41 mPa时,涂层表面呈“片状”结构,粒径大小约1~4μm。所制备出PDA/NDM涂层润湿角均大于150°,属于超疏水,且涂层具有良好的化学稳定性、耐热性、耐磨性以及耐腐蚀性。本工作对圆管内表面涂层的制备和表面纳微结构的调控具有一定的指导意义。

Super-hydrophobic coatings have great application potential in the fields of surface self-cleaning, fluid drag reduction, anti-fog and anti-icing, and microfluidic control. The controls of morphologies for the super hydrophobic coating inside a circular tube have not been investigated. In this paper, the polydopamine (PDA) was coated on the inner wall of stainless-steel cylinder by electrochemical deposition under different values of shear stress, and n-dodecyl mercaptan (NDM) was used to modify the PDA surface. This PDA/NDM coating shows super hydrophobic behavior. Scanning electron microscopy (SEM), contact angle tester (CA), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction tester (XRD) were used to analyze the characterization of the coating. The results show that PDA deposition can be divided into two stages under the effect of shear stress. The first stage is the agglomeration of PDA particles on the stainless steel substrate. The second stage is PDA in-situ growth based on PDA particles aggregate, and the growth process is controlled by shear stress. When the shear stress is 1.85 mPa, the coating surface shows coral shaped balls with about 15-24 μm. When the shear stress is 7.41 mPa, the coating surface has a flaky structure with a particle size of about 1-4 μm. The wetting angles of the prepared PDA/NDM coating are greater than 150°, belongs to super-hydrophobic properties. And the coating has good chemical stability and heat resistance wear resistance and corrosion resistance. The work has certain guiding for the regulation and control of the surface nano/microstructure during the preparation of the inner surface coating of the pipe.