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http://dx.doi.org/10.5407/JKSV.2018.16.2.016

Measurement of Dynamic Contact Angle of Droplet on Moving Hydrophobic and Hydrophilic Surfaces  

Song, Jungyu (Kyung Hee University, Graduate School)
Kim, Hyungdae (Kyung Hee University, Graduate School)
Publication Information
Journal of the Korean Society of Visualization / v.16, no.2, 2018 , pp. 16-22 More about this Journal
Abstract
This study investigates dynamic wetting behaviors of a water droplet placed on surfaces with different wettability and nano-structures. Hydrophobic and hydrophilic properties on as-received silicon wafers were prepared by fabricating thin films of hydrophobic polymer and hydrophilic nanoparticles via layer-by-layer coating. Dynamic advancing contact angle of droplets on the prepared surfaces was measured at various moving velocities of triple contact line with a high-speed video camera. As advancing velocity of triple contact line increased, dynamic advancing contact angle on the as-received silicon and hydrophobic surfaces sharply increased up to $80^{\circ}$ in the range of order of mm/sec whereas the SiO2 nanoparticle-coated hydrophilic surface maintained low contact angles of about $30^{\circ}$ and then it gradually increased in the velocity range of order of hundred mm/sec. The improved dynamic wetting ability observed on the nanostructured hydrophilic surface can benefit the performance of various phase-change heat transfer phenomena under forced convective flow.
Keywords
Dynamic Contact Angle; Wettability;
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