Low Temperature Wetting Behaviour and Droplet Freezing Delay of Thermally Sprayed Polymer Coatings
Bayat Hiisi, Nastaran Niina (2025)
2025
Master's Programme in Materials Science and Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
Hyväksymispäivämäärä
2025-10-06
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202510029649
https://urn.fi/URN:NBN:fi:tuni-202510029649
Tiivistelmä
Ice accumulation on engineering surfaces poses critical challenges in sectors such as aerospace, transportation, and infrastructure, often resulting in safety concerns and increased maintenance costs. The formation of ice is closely linked to the surface's wetting behaviour and freezing delay characteristics, which can be influenced by surface modifications such as polymer coatings. This thesis explores the low-temperature wetting behavior and droplet freezing delay of thermally sprayed polymer coatings, specifically polyethylene coatings applied through the flame spraying technique.
The research examines ten different coated substrates, including stainless steel, aluminium, and glass, comparing their wettability and freezing behavior to their uncoated reference samples. Contact angle measurements were conducted using a droplet shape analyser at room temperature and at freezing conditions (-10°C). The study also evaluated freezing delay by monitoring the time required for water droplets to solidify under controlled low-temperature conditions.
Results indicate that polyethylene coatings significantly increase surface hydrophobicity, as evidenced by increased static and dynamic contact angles in comparison to uncoated surfaces. Furthermore, the coatings effectively delay droplet freezing, with the extent of delay varying based on substrate material. Glass and aluminium substrates coated with polyethylene demonstrated the longest freezing delays. These findings suggest that thermally sprayed polymer coatings can significantly enhance anti-icing performance in cold environments.
Additionally, optical microscopy was employed to assess coating thickness and uniformity, confirming the dense and well-adhered nature of the polyethylene coatings. The study underscores the potential of flame-sprayed polyethylene as a passive icephobic surface treatment for improving the durability and functionality of critical surfaces in subfreezing applications.
This work was done as a part of the SOUNDofICE project. The project is funded by the European Commission through the H2020-FETOPEN.
The research examines ten different coated substrates, including stainless steel, aluminium, and glass, comparing their wettability and freezing behavior to their uncoated reference samples. Contact angle measurements were conducted using a droplet shape analyser at room temperature and at freezing conditions (-10°C). The study also evaluated freezing delay by monitoring the time required for water droplets to solidify under controlled low-temperature conditions.
Results indicate that polyethylene coatings significantly increase surface hydrophobicity, as evidenced by increased static and dynamic contact angles in comparison to uncoated surfaces. Furthermore, the coatings effectively delay droplet freezing, with the extent of delay varying based on substrate material. Glass and aluminium substrates coated with polyethylene demonstrated the longest freezing delays. These findings suggest that thermally sprayed polymer coatings can significantly enhance anti-icing performance in cold environments.
Additionally, optical microscopy was employed to assess coating thickness and uniformity, confirming the dense and well-adhered nature of the polyethylene coatings. The study underscores the potential of flame-sprayed polyethylene as a passive icephobic surface treatment for improving the durability and functionality of critical surfaces in subfreezing applications.
This work was done as a part of the SOUNDofICE project. The project is funded by the European Commission through the H2020-FETOPEN.