{"corpus_id":20830884,"paper_sha":"eba9dbb3b4091e96d7277acc78028507e30fa4b8","doi":"10.1038/nphys2980","arxiv_id":"1406.3203","pmid":28553363,"pmcid":"5444522","mag_id":2161264820,"dblp_id":null,"acl_id":null,"title":"Pancake bouncing on superhydrophobic surfaces","year":2014,"publication_date":"2014-06-08","venue":"Nature Physics","journal":{"name":"Nature physics","pages":"515 - 519","volume":"10"},"journal_issn":null,"journal_title":null,"publication_types":["JournalArticle"],"pubmed_pub_types":["Journal Article"],"s2_fields_of_study":["Medicine","Materials Science","Physics","Engineering"],"reference_count":30,"citation_count":881,"influential_citation_count":7,"is_open_access":true,"arxiv_categories":["cond-mat.soft","cond-mat.mtrl-sci","physics.flu-dyn"],"arxiv_license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","arxiv_journal_ref":null,"mesh_headings":null,"chemicals":null,"comments_corrections":null,"source_flags":5,"s2_open_access_pdf_url":"https://www.nature.com/articles/nphys2980.pdf","s2_open_access_landing_url":"https://www.semanticscholar.org/paper/eba9dbb3b4091e96d7277acc78028507e30fa4b8","s2_open_access_license":null,"s2_open_access_status":"BRONZE","pmc_open_access_pdf_url":null,"pmc_open_access_landing_url":null,"pmc_open_access_license":null,"pmc_open_access_status":null,"unpaywall_open_access_pdf_url":null,"unpaywall_open_access_landing_url":null,"unpaywall_open_access_license":null,"unpaywall_open_access_status":null,"abstract":"When a water drop bounces back from a hydrophobic surface, its initial, spherical shape is usually restored. Now, experiments with a specially engineered superhydrophobic surface made from micrometre-sized tapered pillars covered with copper oxide ‘nanoflowers’ show that droplets can bounce back with a flat, pancake-like shape. Engineering surfaces that promote rapid drop detachment1,2 is of importance to a wide range of applications including anti-icing3,4,5, dropwise condensation6 and self-cleaning7,8,9. Here we show how superhydrophobic surfaces patterned with lattices of submillimetre-scale posts decorated with nanotextures can generate a counter-intuitive bouncing regime: drops spread on impact and then leave the surface in a flattened, pancake shape without retracting. This allows a fourfold reduction in contact time compared with conventional complete rebound 1,10,11,12,13. We demonstrate that the pancake bouncing results from the rectification of capillary energy stored in the penetrated liquid into upward motion adequate to lift the drop. Moreover, the timescales for lateral drop spreading over the surface and for vertical motion must be comparable. In particular, by designing surfaces with tapered micro/nanotextures that behave as harmonic springs, the timescales become independent of the impact velocity, allowing the occurrence of pancake bouncing and rapid drop detachment over a wide range of impact velocities.","claims":[{"public_id":"cl_baf7fbbed2dd9a7017ca1b7d4b3533a6","status":"active","text":"Pancake bouncing arises from rectification of capillary energy stored in penetrated liquid into upward motion sufficient to lift the drop.","confidence":0.94,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_baf7fbbed2dd9a7017ca1b7d4b3533a6"},{"public_id":"cl_ef8525df77a15826ac41b7df21a80359","status":"active","text":"Pancake bouncing reduces contact time by fourfold compared with conventional complete rebound.","confidence":0.97,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_ef8525df77a15826ac41b7df21a80359"},{"public_id":"cl_f4eabead21e17908a77538a7b43135b4","status":"active","text":"Superhydrophobic surfaces patterned with lattices of submillimetre-scale posts decorated with nanotextures can produce a pancake bouncing regime in which drops leave the surface in a flattened shape without retracting.","confidence":0.98,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_f4eabead21e17908a77538a7b43135b4"},{"public_id":"cl_9882c421806b6f4b47a2df2ff4e5db7d","status":"active","text":"Tapered micro/nanotextures that behave as harmonic springs make the relevant spreading and vertical-motion timescales independent of impact velocity, enabling pancake bouncing over a wide range of impact velocities.","confidence":0.95,"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/claims/cl_9882c421806b6f4b47a2df2ff4e5db7d"}],"concepts":[{"public_id":"co_131d521c4012a5f2f74538a919f3d325","status":"active","name":"contact time","description":"The duration for which a droplet remains in contact with the surface during impact and rebound.","types":["measurement"],"aliases":[],"contributors":[{"id":1,"public_id":"12632b8b5f","public_label":"Anonymous (12632b8b5f)","roles":["extraction"],"url":"https://sah.borca.ai/u/12632b8b5f"}],"url":"https://sah.borca.ai/concepts/co_131d521c4012a5f2f74538a919f3d325"},{"public_id":"co_2b1090a380725967f0ec662ab4255ef8","status":"active","name":"harmonic springs","description":"A spring-like mechanical behavior used here to describe the 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