TY - JOUR
T1 - Evaporation of a Sessile Colloidal Water-Glycerol Droplet
T2 - Marangoni Ring Formation
AU - Thayyil Raju, Lijun
AU - Diddens, Christian
AU - Li, Yaxing
AU - Marin, Alvaro
AU - van der Linden, Marjolein N.
AU - Zhang, Xuehua
AU - Lohse, Detlef
N1 - Funding Information:
The authors thank Olga Koshkina and Katharina Landfester for providing fluorescent silica particles. L.T.R. is thankful to Uddalok Sen and Minkush Kansal for fruitful discussions. This work was supported by an Industrial Partnership Programme of the Netherlands Organisation for Scientific Research (NWO), co-financed by Canon Production Printing Netherlands B.V., University of Twente, and Eindhoven University of Technology. D.L. and A.M. acknowledge the funding from European Research Council with Advanced Grant DDD (no. 740479) and Starting Grant (no. 678573), respectively. X.Z. acknowledges the support by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Future Energy Systems (Canada First Research Excellence Fund) and the funding from the Canada Research Chairs program.
Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.
PY - 2022/10/4
Y1 - 2022/10/4
N2 - The transport and aggregation of particles in suspensions is an important process in many physicochemical and industrial processes. In this work, we study the transport of particles in an evaporating binary droplet. Surprisingly, the accumulation of particles occurs not only at the contact line (due to the coffee-stain effect) or at the solid substrate (due to sedimentation) but also at a particular radial position near the liquid-air interface, forming a "ring", which we term as the Marangoni ring. The formation of this ring is primarily attributed to the solutal Marangoni flow triggered by the evaporation dynamics of the water-glycerol droplet. Experiments and simulations show fair agreement in the volume evolution and the general structure of the solutal Marangoni flow, that is, the Marangoni vortex. Experiments show that the location of the Marangoni ring is strongly correlated with the Marangoni vortex. However, finite element numerical simulations fail to describe the particle distribution seen in the experiments. Interestingly, the particles not only accumulate to form the Marangoni ring but also assemble as colloidal crystals close to the liquid-air interface, yielding iridescence. The formation of the colloidal crystals in the experiments is strong evidence that non-hydrodynamic interactions, which are not represented in the simulations, also play a significant role in our system.
AB - The transport and aggregation of particles in suspensions is an important process in many physicochemical and industrial processes. In this work, we study the transport of particles in an evaporating binary droplet. Surprisingly, the accumulation of particles occurs not only at the contact line (due to the coffee-stain effect) or at the solid substrate (due to sedimentation) but also at a particular radial position near the liquid-air interface, forming a "ring", which we term as the Marangoni ring. The formation of this ring is primarily attributed to the solutal Marangoni flow triggered by the evaporation dynamics of the water-glycerol droplet. Experiments and simulations show fair agreement in the volume evolution and the general structure of the solutal Marangoni flow, that is, the Marangoni vortex. Experiments show that the location of the Marangoni ring is strongly correlated with the Marangoni vortex. However, finite element numerical simulations fail to describe the particle distribution seen in the experiments. Interestingly, the particles not only accumulate to form the Marangoni ring but also assemble as colloidal crystals close to the liquid-air interface, yielding iridescence. The formation of the colloidal crystals in the experiments is strong evidence that non-hydrodynamic interactions, which are not represented in the simulations, also play a significant role in our system.
KW - UT-Hybrid-D
UR - http://www.scopus.com/inward/record.url?scp=85138607312&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.2c01949
DO - 10.1021/acs.langmuir.2c01949
M3 - Article
AN - SCOPUS:85138607312
SN - 0743-7463
VL - 38
SP - 12082
EP - 12094
JO - Langmuir
JF - Langmuir
IS - 39
ER -