TY - JOUR
T1 - Drops That Change Their Mind
T2 - Spontaneous Reversal from Spreading to Retraction
AU - Tadmor, R.
AU - Baksi, A.
AU - Gulec, S.
AU - Jadhav, S.
AU - N'Guessan, H. E.
AU - Sen, K.
AU - Somasi, V.
AU - Tadmor, M.
AU - Wasnik, P.
AU - Yadav, S.
N1 - Funding Information: This study was supported by NSF grants CMMI-1405109, CBET-1428398, and CBET-0960229. S.G. and S.Y. acknowledge support from the Houston chapter of the STLE. Publisher Copyright: © 2019 American Chemical Society.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - A liquid drop may spread faster on surfaces when surfactants are added. Here we show that after some time the spreading in such systems can, under certain conditions, spontaneously reverse to retraction and the droplet pulls itself back, receding from areas it has just recently wetted, elevating its center of mass in a jerklike motion. The duration from drop placement to the onset of retraction ranges from hours to less than a second primarily as a function of surfactant concentration. When the retraction is asymmetric, it results in drop motion, and when it is symmetric, the mass of the drop collects itself on its spot. This phenomenon, which was predicted theoretically in 2014, is apparently a general one for drops with surfactants; however, other factors, such as evaporation and contamination, prevented its observance so far.
AB - A liquid drop may spread faster on surfaces when surfactants are added. Here we show that after some time the spreading in such systems can, under certain conditions, spontaneously reverse to retraction and the droplet pulls itself back, receding from areas it has just recently wetted, elevating its center of mass in a jerklike motion. The duration from drop placement to the onset of retraction ranges from hours to less than a second primarily as a function of surfactant concentration. When the retraction is asymmetric, it results in drop motion, and when it is symmetric, the mass of the drop collects itself on its spot. This phenomenon, which was predicted theoretically in 2014, is apparently a general one for drops with surfactants; however, other factors, such as evaporation and contamination, prevented its observance so far.
UR - http://www.scopus.com/inward/record.url?scp=85072032740&partnerID=8YFLogxK
U2 - https://doi.org/10.1021/acs.langmuir.9b02592
DO - https://doi.org/10.1021/acs.langmuir.9b02592
M3 - Article
SN - 0743-7463
JO - Langmuir
JF - Langmuir
ER -