Surface modification via atomic layer deposition Julie Jalila Kalmoni , Frances L. Heale, Christopher S. Blackman and Claire J. Carmalt Materials Chemistry Centre, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom Superhydrophobicity, a common property within the field of protective coatings, was first observed in Lotus leaves where water droplets roll off the surface, taking dirt particles with them, rather than wet it [1,2]. To replicate this process on a synthetic scale, both micro-/nano-scale roughness and a low surface energy reagent are required [3] . The latter employs the use of toxic fluorinated polymers (which also contributes to the robustness and high transparencies of the films) and requires high depositional temperatures [4,5]. However the widespread application of superhydrophobic coatings has been hindered due to their typically poor durability or robustness [6] . A relatively unexplored technique combines the use of aerosol-assisted chemical vapour deposition (AACVD) of polymer films along with the resultant surface modification via atomic layer deposition (ALD). ALD, a branch of chemical vapour deposition (CVD), is a technique used to deposit atomic layers of complex and layered thin films. By operating at such a scale, beneficial properties such as thickness control, conformality of the films and good adhesion are possible [7] . Operational advantages include low temperature depositions. This research seeks to fabricate fluoride-free superhydrophobic films from simple and non-toxic compounds via AACVD. This depositional technique also provides the highly textured morphology required. Thereafter, the surfaces’ properties are modified via the ALD of metal oxides. Thus far, thin films with a rough morphology, formed through island growth of aggregates have been produced, displaying static water contact angles > 160°, transparencies > 40% and maintained superhydrophobicity after 300 tape peel cycles. This novel route could be used to produce ‘easy-to-clean’ coatings for slip-resistant flooring as well as coatings on solar cells. References 1. W. Barthlott and C. Neinhuis, Planta , 1997, 202 , 1–8. 2. J. Jeevahan, M. Chandrasekaran, G. Britto Joseph, R. B. Durairaj and G. Mageshwaran, J. Coatings Technol. Res. , 2018, 15 , 231–250. 3. X. J. Guo, C. H. Xue, S. Sathasivam, K. Page, G. He, J. Guo, P. Promdet, F. L. Heale, C. J. Carmalt and I. P. Parkin, J. Mater. Chem. A , 2019, 7 , 17604–17612. 4. J. Y. Huang, S. H. Li, M. Z. Ge, L. N. Wang, T. L. Xing, G. Q. Chen, X. F. Liu, S. S. Al-Deyab, K. Q. Zhang, T. Chen and Y. K. Lai, J. Mater. Chem. A , 2015, 3 , 2825–2832. 5. V. H. Dalvi and P. J. Rossky, Proc. Natl. Acad. Sci. U. S. A. , 2010, 107 , 13603–13607. 6. F. Chen, Y. Wang, Y. Tian, D. Zhang, J. Song, C. R. Crick, C. J. Carmalt, I. P. Parkin and Y. Lu, Chem. Soc. Rev. , 2022, 51 , 8476–8583. 7. R. W. Johnson, A. Hultqvist and S. F. Bent, Mater. Today , 2014, 17 , 236–246.
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