大气压等离子体射流制备超疏水涂层及其减阻研究
发布时间：2018-08-26 17:47
【摘要】：超疏水表面独特的润湿性使其在自清洁材料、海洋抗蚀减阻方面及生物医学领域等有着广阔的应用前景。制备超疏水表面一般包括两种方法,一是在低表面能物质表面构筑粗糙结构,二是在粗糙固体表面修饰低表面能物质。目前,大多数制备方法由于受到各种工艺条件的制约,存在成本高、周期长、制备工艺复杂、需要特殊设备等问题,大气压等离子体射流沉积方法可直接在大气环境中沉积,具有工序简单,沉积效率高,操作安全,生产成本低等特点,为大面积制备超疏水涂层提供了可行性。本文采用大气压等离子体射流沉积设备,以六甲基二硅氧烷(HMDSO)为反应单体,Ar为载气体,在铝合金及其带漆表面制备超疏水涂层。经接触角仪测试,制备的涂层表面接触角由原来的78o提高到162o,滚动角由90o降低至1o,表现出优异的超疏水性,说明在大气环境中等离子体射流处理能显著地改变亲水试样表面的润湿性。为研究超疏水表面的润湿机制,分别采用SEM、EDX、FTIR等测试手段对其表面结构及化学组成进行分析,结果表明超疏水涂层是由微纳米级颗粒堆积而成,堆积过程中形成了大量的孔隙和空洞。构成涂层的主要元素是Si和O,这种硅氧化合物形成具有低表面能的Si-O-Si网络状结构,这两者共同促成了涂层表面润湿性的降低,水滴在其表面呈球形分布,微小倾角便能自由滚落,表现出优异的超疏水性。对等离子体沉积超疏水涂层的耐久性进行分析,结果显示其在大气中放置10个月后仍具超疏水性,在酸碱等腐蚀溶液中浸泡一段时间后仍能保持高的接触角和滚动角,耐候性得到保证。同时对超疏水涂层在水流环境中的稳定性进行了相关测试,结果表明,随着水流速的增加和水流时间的延长,附着于金属板表面的超疏水涂层受破坏程度随之增大,疏水效果呈下降趋势。对超疏水涂层覆盖的碳钢试样进行海水腐蚀试验,对比裸露钢基底,超疏水涂层试样表面锈蚀情况明显降低。电化学分析表明,带超疏水涂层的金属试样自腐蚀电位有提高,自腐蚀电流密度降低,且其阻抗值明显增加,超疏水涂层的存在减缓了试样发生腐蚀的倾向。通过差压流阻测试装置对所制备超疏水涂层的水下减阻性能进行检测,结果表明,在水流速度逐渐增加过程中,超疏水涂层试样表面减阻效果呈现出先增大后减小趋势,在流速约为2.5m/s时存在一个最大值,即DR=37%。对其减阻机制进行分析,疏水涂层表面与水接触模式以气液接触为主,容易形成滑移流动,造成边界剪切力为零而使水流在流经固体表面时的摩擦阻力大大减小,最终产生减阻效果。超疏水表面的这一减阻特性使其在船舶、舰艇等各种水下航行器上具有广泛的应用价值。
[Abstract]:The unique wettability of superhydrophobic surface makes it promising in the fields of self-cleaning materials, marine corrosion resistance and drag reduction, biomedicine and so on. The preparation of superhydrophobic surface generally includes two methods: one is to construct rough structure on the surface of low surface energy substance, the other is to modify low surface energy substance on rough solid surface. At present, most of the preparation methods are restricted by various technological conditions, such as high cost, long period, complex preparation process and special equipment. Atmospheric pressure plasma jet deposition can be directly deposited in the atmospheric environment. It has the advantages of simple working procedure, high deposition efficiency, safe operation and low production cost, which provides the feasibility for the preparation of superhydrophobic coatings in large area. A superhydrophobic coating was prepared on aluminum alloy and its lacquer surface by atmospheric pressure plasma jet deposition equipment using hexamethyldisiloxane (HMDSO) as reaction monomer and ar as carrier gas. The contact angle of the coating was increased from 78o to 162o, and the rolling angle was reduced from 90o to 1o, which showed excellent hydrophobicity. The results show that the surface wettability of the hydrophilic sample can be significantly changed by plasma jet treatment in atmospheric environment. In order to study the wetting mechanism of superhydrophobic surface, the surface structure and chemical composition of superhydrophobic coating were analyzed by means of SEM,EDX,FTIR, respectively. The results showed that the superhydrophobic coating was formed by the accumulation of micro and nanometer particles. A large number of pores and voids are formed during the accumulation process. The main elements of the coating are Si and O, which form a Si-O-Si network structure with low surface energy. Both of them contribute to the decrease of the wettability of the coating surface and the distribution of water droplets on the coating surface. Small dip angles can roll freely, showing excellent hydrophobicity. The durability of superhydrophobic coating deposited by plasma deposition is analyzed. The results show that the coating is still super hydrophobic after being placed in atmosphere for 10 months, and it can maintain high contact angle and rolling angle after soaking in corrosion solution such as acid and alkali for a period of time. Weather resistance is guaranteed. At the same time, the stability of superhydrophobic coating in water flow environment is tested. The results show that with the increase of water flow velocity and the prolongation of water flow time, the damage degree of superhydrophobic coating attached to the surface of metal plate increases. The hydrophobic effect showed a downward trend. The corrosion test of carbon steel coated with superhydrophobic coating was carried out in seawater. Compared with the bare steel substrate, the corrosion on the surface of the superhydrophobic coating sample was obviously reduced. The electrochemical analysis showed that the corrosion potential of the metal sample with superhydrophobic coating was increased, the corrosion current density was decreased, and its impedance value was obviously increased. The existence of superhydrophobic coating slowed down the corrosion tendency of the sample. The underwater drag reduction performance of the superhydrophobic coating was tested by differential pressure flow resistance test device. The results showed that the drag reduction effect of the superhydrophobic coating on the surface of the superhydrophobic coating increased first and then decreased in the process of increasing the flow velocity. There is a maximum when the flow rate is about 2.5m/s, that is, DR=37%. The mechanism of drag reduction is analyzed. The main contact mode between hydrophobic coating surface and water is gas-liquid contact, which is easy to form slip flow, resulting in zero boundary shear force and greatly reducing the friction resistance of flow through solid surface. Finally, the drag reduction effect is produced. This drag reduction characteristic of superhydrophobic surface makes it widely used in various underwater vehicles such as ships and ships.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB306
本文编号：2205685
[Abstract]:The unique wettability of superhydrophobic surface makes it promising in the fields of self-cleaning materials, marine corrosion resistance and drag reduction, biomedicine and so on. The preparation of superhydrophobic surface generally includes two methods: one is to construct rough structure on the surface of low surface energy substance, the other is to modify low surface energy substance on rough solid surface. At present, most of the preparation methods are restricted by various technological conditions, such as high cost, long period, complex preparation process and special equipment. Atmospheric pressure plasma jet deposition can be directly deposited in the atmospheric environment. It has the advantages of simple working procedure, high deposition efficiency, safe operation and low production cost, which provides the feasibility for the preparation of superhydrophobic coatings in large area. A superhydrophobic coating was prepared on aluminum alloy and its lacquer surface by atmospheric pressure plasma jet deposition equipment using hexamethyldisiloxane (HMDSO) as reaction monomer and ar as carrier gas. The contact angle of the coating was increased from 78o to 162o, and the rolling angle was reduced from 90o to 1o, which showed excellent hydrophobicity. The results show that the surface wettability of the hydrophilic sample can be significantly changed by plasma jet treatment in atmospheric environment. In order to study the wetting mechanism of superhydrophobic surface, the surface structure and chemical composition of superhydrophobic coating were analyzed by means of SEM,EDX,FTIR, respectively. The results showed that the superhydrophobic coating was formed by the accumulation of micro and nanometer particles. A large number of pores and voids are formed during the accumulation process. The main elements of the coating are Si and O, which form a Si-O-Si network structure with low surface energy. Both of them contribute to the decrease of the wettability of the coating surface and the distribution of water droplets on the coating surface. Small dip angles can roll freely, showing excellent hydrophobicity. The durability of superhydrophobic coating deposited by plasma deposition is analyzed. The results show that the coating is still super hydrophobic after being placed in atmosphere for 10 months, and it can maintain high contact angle and rolling angle after soaking in corrosion solution such as acid and alkali for a period of time. Weather resistance is guaranteed. At the same time, the stability of superhydrophobic coating in water flow environment is tested. The results show that with the increase of water flow velocity and the prolongation of water flow time, the damage degree of superhydrophobic coating attached to the surface of metal plate increases. The hydrophobic effect showed a downward trend. The corrosion test of carbon steel coated with superhydrophobic coating was carried out in seawater. Compared with the bare steel substrate, the corrosion on the surface of the superhydrophobic coating sample was obviously reduced. The electrochemical analysis showed that the corrosion potential of the metal sample with superhydrophobic coating was increased, the corrosion current density was decreased, and its impedance value was obviously increased. The existence of superhydrophobic coating slowed down the corrosion tendency of the sample. The underwater drag reduction performance of the superhydrophobic coating was tested by differential pressure flow resistance test device. The results showed that the drag reduction effect of the superhydrophobic coating on the surface of the superhydrophobic coating increased first and then decreased in the process of increasing the flow velocity. There is a maximum when the flow rate is about 2.5m/s, that is, DR=37%. The mechanism of drag reduction is analyzed. The main contact mode between hydrophobic coating surface and water is gas-liquid contact, which is easy to form slip flow, resulting in zero boundary shear force and greatly reducing the friction resistance of flow through solid surface. Finally, the drag reduction effect is produced. This drag reduction characteristic of superhydrophobic surface makes it widely used in various underwater vehicles such as ships and ships.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB306
【参考文献】
相关期刊论文 前4条
1 李济吾;唐志鹏;;电晕放电与络合催化联合同时去除烟气中SO_2、NO实验研究[J];环境科学学报;2015年01期
2 顾建农;晏欣;张志宏;赵昕;;基于PIV测量的柔性壁减阻试验[J];舰船科学技术;2012年11期
3 轩俭勇;骆仲泱;赵磊;江建平;高翔;;脉冲电晕放电电子能量及OH,O或O_3对NO氧化的光谱学研究[J];光谱学与光谱分析;2012年05期
4 江雷;从自然到仿生的超疏水纳米界面材料[J];新材料产业;2003年03期
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