Fabrication and application of icephobic silicone coatings on epoxy substrate

• Published in: Progress in organic coatings 2021-12, Vol.161, p.106483, Article 106483
• Main Authors: Zheng, Qinwen, Lv, Jian, Zhang, Jing, Feng, Jie
• Format: Article
• Language: English
• Subjects: Adhesion tests; Adhesive strength; Coating; Coatings; Contact angle; Crosslinking; Electric contacts; Electric power systems; Epoxy; Epoxy resins; Freezing; High speed rail; Hydrophobicity; Ice; Ice formation; Icephobic; Icephobicity; Mechanical properties; Modulus of elasticity; PDMS; Polydimethylsiloxane; Primers (coatings); Silicone resins; Siloxane; Siloxanes; Substrates; Surface energy; Tensile tests; Winter
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2021.106483

In winter, when the trains run at high speed, snow that falls on the track is easily drawn onto the bottom of the train, and quickly forms ice. Such icing may cause serious safety issues. In this paper, the epoxy resin is used as a primary coat and a hydroxyl-terminated silicone oil (PDMS) was coated on it. Siloxane, with amido or epoxy terminal group, named KH 550 or KH 560, respectively, was used as a co-crosslinking agent of the epoxy and PDMS in order to ensure high adhesive strength between the two layers. The hydrophobic, icephobic and mechanical properties of the coatings were characterized by contact angle measurements, ice-adhesion tests and tensile tests, respectively. The results show that the contact angle of the PDMS coating crosslinked by the KH 550 reaches 114.1°, and it can still show good hydrophobic properties after being immersed in water for 10 days. The adhesive strength of the ice on the PDMS coating is only 2.5% of that of ice on the epoxy coating. The low surface energy and the low elastic modulus should be responsible for the excellent icephobic properties. Moreover, the bonding force between the PDMS coating and the epoxy primer is also excellent. When the KH 560 was used as the co-crosslinking agent, the hydrophobic and icephobic properties of the top PDMS coating were improved due to its week polarity compared with KH 550. This study will be helpful in resolving the problems associated with the running of high speed trains in winter or the electric power system which requires resistance to freezing rain. In this paper, the epoxy resin is used as a primary coat and a hydroxyl-terminated silicone oil (PDMS) was coated on it. Siloxane with amido or epoxy terminal group, named KH550 or KH560, was used as a co-crosslinking agent of the epoxy and PDMS in order to ensure high adhesive strength between the two layers. The results show that the bonding force between the two layers is higher than the tensile strength of the PDMS coating itself. The adhesive strength of the ice on the PDMS coating is only 2.5% of that of ice on the epoxy coating. The low surface energy and the low elastic modulus should be responsible for the excellent icephobic properties. The study will be helpful for the development of icephobic coatings for high-speed trains and electrical power systems working in winter. [Display omitted] •PDMS top coat with high hydrophobic surface is fabricated on an epoxy coat by “wet to wet” coating and co-crosslinking.•Siloxane w