Effect of heterogeneity on hydro/ice-phobic properties of alkylsilane/fluoro-alkylsilane-based coatings on Al substrates

• Published in: JCT research 2017, Vol.14 (1), p.267-275
• Main Authors: Arianpour, F., Farhadi, S., Farzaneh, M.
• Format: Article
• Language: English
• Subjects: Adhesive strength; Aluminum; Aluminum base alloys; Chemistry and Materials Science; Coating effects; Contact angle; Corrosion and Coatings; Hydrophobicity; Icephobicity; Industrial Chemistry/Chemical Engineering; Materials Science; Multilayers; Organic chemistry; Polymer Sciences; Scanning electron microscopy; Submerging; Substrates; Surfaces and Interfaces; Thin Films; Tribology; X ray spectra
• ISSN: 1547-0091; 1935-3804; 2168-8028
• DOI: 10.1007/s11998-016-9819-z

In this work, hydrophobic and anti-ice performances of heterogeneous coatings (HCs) were studied. Multilayer thin films of homogeneous and heterogeneous chemically different alkylsilane compounds, i.e., octadecyltrichlorosilane (OD) and 1 H ,1 H ,2 H ,2 H -perfluorooctyltrichlorosilane (PF) were fabricated by alkylsilane/fluoro-alkylsilane deposition on a flat aluminum alloy (AA6061) substrate. The contact angle (CA) values for the homogeneous coatings of OD–OD and PF–PF after a 12-h immersion time (IT) were ~140° and ~120°, respectively. However, significant improvements in CA values were observed for the HCs, PF–OD and OD–PF, with CA values of ~154° and ~160°, respectively, for a 12-h IT. Moreover, very small contact angle hysteresis (CAH) values of ~6°–7° were obtained for PF–OD and OD–PF, whereas large CAH values of ~40°–65° were obtained for the homogeneous coatings. Scanning electron microscopy of the coated surfaces showed a rough structure at the micro-/nano-meter scale and X-ray photoelectron spectroscopy analysis indicated the presence of alkylsilane and/or fluoro-alkylsilane molecules on polished aluminum surfaces. The ice adhesion reduction factor ( ARF ) of OD–OD and PF–PF homogeneous coatings shows that ice adhesion strength is about 1.5 and 1.7 times lower, respectively, than that obtained on a polished bare Al sample. However, the ARF of PF–OD and OD–PF HCs shows that ice adhesion strength is about 2.7 and 3.5 times, respectively, lower than that obtained on a polished bare Al sample.