Abstract
Superomniphobic, i.e. liquid-repellent, surfaces have been an interesting area of research during recent years due to their various potential applications. However, producing such surfaces, especially on hard and resilient substrates like stainless steel, still remains challenging. We present a stepwise fabrication process of a multilayered nanocoating on a stainless steel substrate, consisting of a nanoparticle layer, a nanofilm, and a layer of silane molecules. Liquid flame spray was used to deposit a TiO2 nanoparticle layer as the bottom layer for producing a suitable surface structure. The interstitial Al2O3 nanofilm, fabricated by atomic layer deposition (ALD), stabilized the nanoparticle layer, and the topmost fluorosilane layer lowered the surface energy of the coating for enhanced omniphobicity. The coating was characterized with field emission scanning electron microscopy, focused ion beam scanning electron microscopy, x-ray photoelectron spectroscopy, contact angle (CA) and sliding angle (SA) measurements, and microscratch testing. The widely recognized requirements for superrepellency, i.e. CA > 150° and SA < 10°, were achieved for deioinized water, diiodomethane, and ethylene glycol. The mechanical stability of the coating could be varied by tuning the thickness of the ALD layer at the expense of repellency. To our knowledge, this is the thinnest superomniphobic coating reported so far, with the average thickness of about 70 nm.
Original language | English |
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Article number | 185708 |
Journal | Nanotechnology |
Volume | 29 |
Issue number | 18 |
DOIs | |
Publication status | Published - 9 Mar 2018 |
MoE publication type | A1 Journal article-refereed |
Funding
The work was performed within the DIMECC HYBRIDS (Hybrid Materials) program. We are grateful to Fiskars Finland Oy Ab for providing the stainless steel substrates used in this study. We would also like to thank Prof Minnamari Vippola from Materials Science at TUT for interpreting some of the results. Funding sources We want to acknowledge the financial support of the Finnish Funding Agency for Innovation (Tekes, grant number 1236/13) and all of the participating companies. Janne Haa-panen acknowledges financial support from the Academy of Finland, project ‘Nanostructured large-area antibacterial surfaces (nLABS, grant no 278 846).’ The study was funded by the Finnish Funding Agency for Innovation (Tekes, grant 1236/13). Some of the work hours were funded from a project by the Academy of Finland.
Keywords
- aerosol synthesis
- atomic layer deposition
- liquid flame spray
- multilayered
- nanocoating
- silanization
- superomniphobic