Structure-Activity Relationship between the Superhydrophilic Nanowire Structure and the Oil Dewetting Property

Materials require specific surface structures to achieve the best performance, but achieving an optimal structural design requires a systematic study of how structure affects performance. In this work, we comprehensively and systematically investigated the structure-activity relationship between the nanowire structure and the oil dewetting self-cleaning performance. It is easy for an oil droplet to enter this structure, but it is difficult for it to escape from the gaps between the structures even under the action of water. So, the oil dewetting ability is greatly reduced, showing that this "easy to enter and difficult to exit" mode is very disadvantageous for oil desorption. Moreover, if the structure is dissolved during the test, the oil dewetting ability will be restored. The desorption effect is affected by structural parameters and reaction conditions, which further verifies the negative effect of this structure. In contrast, copper(II) oxide nanowires completely lose their self-cleaning ability due to the enhancement of hydrophobicity and oleophilicity, and the larger-diameter copper(II) oxalate nanorods exhibit a "difficult to enter and difficult to exit" mode, leading to the partial recovery of the oil dewetting performance. This study helps us deeply understand the influence of the surface microstructure on the oil dewetting performance and lay a solid foundation for further appropriate structural design.