Robust and thermal-healing superhydrophobic surfaces by spin-coating of polydimethylsiloxane

Hypothesis: Superhydrophobic surfaces easily lose their excellent water-repellency after damages, which limit their broad applications in practice. Thus, the fabrication of superhydrophobic surfaces with excellent durability and thermal healing should be taken into consideration. Experiments: In this work, robust superhydrophobic surfaces with thermal healing were successfully fabricated by spin-coating method. To achieve superhydrophobicity, cost-less and fluoride-free polydimethylsiloxane (PDMS) was spin-coated on rough aluminum substrates. Findings: After being spin-coated for one cycle, the superhydrophobic PDMS coated hierarchical aluminum (PDMS-H-A1) surfaces showed excellent tolerance to various chemical and mechanical damages in lab, and outdoor damages for 90 days. When the PDMS-H-Al surfaces underwent severe damages such as oil contamination (peanut oil with high boiling point) or sandpaper abrasion (500 g of force for 60 cm), their superhydrophobicity would lose. Interestingly, through a heating process, cyclic oligomers generating from the partially decomposed PDMS acted as low-surface-energy substance on the damaged rough surfaces, leading to the recovery of superhydrophobicity. The relationship between the spin-coating cycles and surface wettability was also investigated. This paper provides a facile, fluoride-free and efficient method to fabricate superhydrophobic surfaces with thermal healing. (C) 2017 Published by Elsevier Inc.