eprintid: 10199818 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/19/98/18 datestamp: 2024-11-08 14:50:21 lastmod: 2024-11-08 14:50:21 status_changed: 2024-11-08 14:50:21 type: proceedings_section metadata_visibility: show sword_depositor: 699 creators_name: Huang, Z creators_name: Long, J creators_name: Luo, K title: Molecular Dynamics Investigation of Wettability Transition of Copper and Design of a Durable Superwetting Structure ispublished: pub divisions: UCL divisions: B04 divisions: F45 abstract: Superwettability of clean metal surfaces cannot endure for extended periods in natural atmospheric conditions. Among the various factors that may contribute to the wettability transition of metals, we believe that the adsorption of organics plays a significant role. In this study, we investigate the impact and extent of adsorbed organics on the wettability of copper through Molecular Dynamics simulations of carboxyl acids adsorbing on its surface. We examine the change in surface energy with increasing coverage ratio of organics. The result reveals that a clean metal surface exhibits high surface energy, corresponding to a superwettability nature. However, as the coverage ratio of organics increases, the wettability decreases and changes to hydrophobic at a coverage ratio of about 0.5-0.6. The simulations indicate that this wettability transition is primarily caused by the water-repelling effect originating from the carbon backbone of the organic molecules. Shorter molecules exhibit lower water-repelling strength and form weaker adsorption structures, leading to a less pronounced wettability transition. To achieve durable superwetting, we propose a porous structure composed of sufficiently small voids that allow water molecules to enter while preventing the penetration of organic molecules. Experimental results demonstrate that this structure enables superwetting to persist for several months in urban atmospheric conditions. These superwetting surfaces hold significant potential for various applications across different domains. date: 2024-01-01 date_type: published publisher: American Society of Mechanical Engineers official_url: http://dx.doi.org/10.1115/mnhmt2024-131175 full_text_type: pub language: eng verified: verified_manual elements_id: 2327397 doi: 10.1115/MNHMT2024-131175 lyricists_name: Luo, Kai lyricists_id: KLUOX54 actors_name: Luo, Kai actors_id: KLUOX54 actors_role: owner full_text_status: restricted pres_type: paper publication: Proceedings of ASME 2024 7th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2024 event_title: ASME 2024 7th International Conference on Micro/Nanoscale Heat and Mass Transfer event_dates: 5 Aug 2024 - 7 Aug 2024 book_title: Proceedings of ASME 2024 7th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2024 citation: Huang, Z; Long, J; Luo, K; (2024) Molecular Dynamics Investigation of Wettability Transition of Copper and Design of a Durable Superwetting Structure. In: Proceedings of ASME 2024 7th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2024. American Society of Mechanical Engineers document_url: https://discovery.ucl.ac.uk/id/eprint/10199818/1/Luo%202024%20MNHMT2024-131175_accept.pdf