{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T13:27:11Z","timestamp":1787318831486,"version":"build-2736575974"},"reference-count":46,"publisher":"Public Library of Science (PLoS)","issue":"7","license":[{"start":{"date-parts":[[2022,7,13]],"date-time":"2022-07-13T00:00:00Z","timestamp":1657670400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Pressing the fingertips into surfaces causes skin deformations that enable humans to grip objects and sense their physical properties. This process involves intricate finger geometry, non-uniform tissue properties, and moisture, complicating the underlying contact mechanics. Here we explore the initial contact evolution of dry and hydrated fingers to isolate the roles of governing physical factors. Two participants gradually pressed an index finger on a glass surface under three moisture conditions: dry, water-hydrated, and glycerin-hydrated. Gross and real contact area were optically measured over time, revealing that glycerin hydration produced strikingly higher real contact area, while gross contact area was similar for all conditions. To elucidate the causes for this phenomenon, we investigated the combined effects of tissue elasticity, skin-surface friction, and fingerprint ridges on contact area using simulation. Our analyses show the dominant influence of elastic modulus over friction and an unusual contact phenomenon, which we call friction-induced hinging.<\/jats:p>","DOI":"10.1371\/journal.pone.0269722","type":"journal-article","created":{"date-parts":[[2022,7,13]],"date-time":"2022-07-13T13:26:43Z","timestamp":1657718803000},"page":"e0269722","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":24,"title":["Contact evolution of dry and hydrated fingertips at initial touch"],"prefix":"10.1371","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9928-0521","authenticated-orcid":true,"given":"Gokhan","family":"Serhat","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasemin","family":"Vardar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katherine J.","family":"Kuchenbecker","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2022,7,13]]},"reference":[{"key":"pone.0269722.ref001","first-page":"141","article-title":"Signals in tactile afferents from the fingers eliciting adaptive motor responses during precision grip","volume":"66","author":"G Westling","year":"1987","journal-title":"Exp Brain Res"},{"key":"pone.0269722.ref002","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1046\/j.1460-9568.2003.02721.x","article-title":"Influence of object shape on responses of human tactile afferents under conditions characteristics of manipulation","volume":"18","author":"P Jenmalm","year":"2003","journal-title":"Eur J Neurosci"},{"key":"pone.0269722.ref003","doi-asserted-by":"crossref","first-page":"345","DOI":"10.1038\/nrn2621","article-title":"Coding and use of tactile signals from the fingertips in object manipulation tasks","volume":"10","author":"RS Johansson","year":"2009","journal-title":"Nat Rev Neurosci"},{"key":"pone.0269722.ref004","doi-asserted-by":"crossref","first-page":"20160935","DOI":"10.1098\/rsif.2016.0935","article-title":"Contact mechanics of the human finger pad under compressive loads","volume":"14","author":"BM Dzidek","year":"2017","journal-title":"J R Soc Interface"},{"key":"pone.0269722.ref005","doi-asserted-by":"crossref","first-page":"20150495","DOI":"10.1098\/rsif.2015.0495","article-title":"Influence of physico-chemical, mechanical and morphological fingerpad properties on the frictional distinction of sticky\/slippery surfaces","volume":"12","author":"P-H Cornault","year":"2015","journal-title":"J R Soc Interface"},{"key":"pone.0269722.ref006","doi-asserted-by":"crossref","first-page":"10864","DOI":"10.1073\/pnas.1706233114","article-title":"Why pens have rubbery grips","volume":"114","author":"B Dzidek","year":"2017","journal-title":"Proc Natl Acad Sci"},{"key":"pone.0269722.ref007","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1109\/TOH.2020.2966992","article-title":"Step-change in friction under electrovibration","volume":"13","author":"I Ozdamar","year":"2020","journal-title":"IEEE Trans Haptics"},{"key":"pone.0269722.ref008","doi-asserted-by":"crossref","first-page":"e2109109118","DOI":"10.1073\/pnas.2109109118","article-title":"Initial contact shapes the perception of friction","volume":"118","author":"L Willemet","year":"2021","journal-title":"Proc Natl Acad Sci"},{"key":"pone.0269722.ref009","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1007\/s11249-007-9206-0","article-title":"Friction and lubrication of human skin","volume":"26","author":"MJ Adams","year":"2007","journal-title":"Tribol Lett"},{"key":"pone.0269722.ref010","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1007\/s11249-009-9530-7","article-title":"Influence of surface roughness, material and climate conditions on the friction of human skin","volume":"37","author":"CP Hendriks","year":"2010","journal-title":"Tribol Lett"},{"key":"pone.0269722.ref011","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1007\/s11249-010-9709-y","article-title":"Understanding the friction mechanisms between the human finger and flat contacting surfaces in moist conditions","volume":"41","author":"SE Tomlinson","year":"2011","journal-title":"Tribol Lett"},{"key":"pone.0269722.ref012","first-page":"303","article-title":"Optimizing a viscoelastic finite element model to represent the dry, natural, and moist human finger pressing on glassIEEE Trans. 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