{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T18:17:02Z","timestamp":1775067422031,"version":"3.50.1"},"reference-count":14,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2011,3,18]],"date-time":"2011-03-18T00:00:00Z","timestamp":1300406400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>We have characterized several dynamic aspects of a simple chemical system capable of self-movement: An oil droplet in water system. We focused on spontaneous mode switching and collective behavior of droplets as emergent properties of the system. Droplets demonstrated spontaneous mode switching by changing speed, direction and acceleration over time, and collective behaviors of droplets resulted from such autonomous characteristics. In this paper, we quantitatively measured those characteristics to show that droplets did not act completely independently in the same system, but tend to be attracted to one another and interact with each other by adjusting their motion.<\/jats:p>","DOI":"10.3390\/e13030709","type":"journal-article","created":{"date-parts":[[2011,3,18]],"date-time":"2011-03-18T10:30:28Z","timestamp":1300444228000},"page":"709-719","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":29,"title":["Mode Switching and Collective Behavior in Chemical Oil Droplets"],"prefix":"10.3390","volume":"13","author":[{"given":"Naoto","family":"Horibe","sequence":"first","affiliation":[{"name":"Department of General Systems Studies, University of Tokyo, Komaba, Tokyo 153, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Martin M.","family":"Hanczyc","sequence":"additional","affiliation":[{"name":"Institute of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takashi","family":"Ikegami","sequence":"additional","affiliation":[{"name":"Department of General Systems Studies, University of Tokyo, Komaba, Tokyo 153, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2011,3,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"19102","DOI":"10.1021\/jp9616876","article-title":"Nonlinear oscillation and ameba-like motion in an oil\/water system","volume":"100","author":"Mangome","year":"1996","journal-title":"J. Phys. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2972","DOI":"10.1103\/PhysRevLett.75.2972","article-title":"Free-running droplets","volume":"75","author":"Ondarcuhu","year":"1995","journal-title":"Phys. Rev. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"041603","DOI":"10.1103\/PhysRevE.72.041603","article-title":"Chemosensitive running droplet","volume":"72","author":"Sumino","year":"2005","journal-title":"Phys. Rev. E"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"051602","DOI":"10.1103\/PhysRevE.65.051602","article-title":"Chemical influences on adsorption-mediated self-propelled drop movement","volume":"65","author":"Lee","year":"2002","journal-title":"Phys. Rev. E"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"068301","DOI":"10.1103\/PhysRevLett.94.068301","article-title":"Self-running droplet: Emergence of regular motion from nonequilibrium noise","volume":"94","author":"Sumino","year":"2005","journal-title":"Phys. Rev. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"046301","DOI":"10.1103\/PhysRevE.70.046301","article-title":"Forward and backward laser-guided motion of an oil droplet","volume":"70","author":"Rybalko","year":"2004","journal-title":"Phys. Rev. E"},{"key":"ref_7","unstructured":"Matsuno, H., Hanczyc, M.M., and Ikegami, T. Self-maintained movements of droplets with convection flow. Proceedings of the 3rd Australian Conference on Progress in Artificial Life."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"9386","DOI":"10.1021\/ja0706955","article-title":"Fatty acid chemistry at the oil-water interface: Self-propelled oil droplets","volume":"129","author":"Hanczyc","year":"2007","journal-title":"J. Am. Chem. Soc."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"5012","DOI":"10.1021\/ja806689p","article-title":"Self-propelled oil droplets consuming \u201cFuel\u201d surfactant","volume":"131","author":"Toyota","year":"2009","journal-title":"J. Am. Chem. Soc."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1162\/artl_a_00002","article-title":"Chemical basis for minimal cognition","volume":"16","author":"Hanczyc","year":"2010","journal-title":"Artif. Life"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Kohonen, T. (2000). Self-Organizing Maps, Springer. [3rd ed.].","DOI":"10.1007\/978-3-642-56927-2"},{"key":"ref_12","unstructured":"Horibe, N., Hanczyc, M.M., and Ikegami, T. (2011). Shape and motion dynamics in self-moving oil droplets. Robot. Auton. Systems, submitted."},{"key":"ref_13","unstructured":"R, Version 2.7.2. Available online: http:\/\/www.r-project.org\/."},{"key":"ref_14","unstructured":"OpenCV, Version 1.1.0. Available online: http:\/\/opencv.willowgarage.com\/wiki\/."}],"container-title":["Entropy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1099-4300\/13\/3\/709\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:55:35Z","timestamp":1760219735000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1099-4300\/13\/3\/709"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2011,3,18]]},"references-count":14,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2011,3]]}},"alternative-id":["e13030709"],"URL":"https:\/\/doi.org\/10.3390\/e13030709","relation":{},"ISSN":["1099-4300"],"issn-type":[{"value":"1099-4300","type":"electronic"}],"subject":[],"published":{"date-parts":[[2011,3,18]]}}}