ISSN オンライン: 2688-7231
ISBN 印刷: 978-1-56700-497-7 (Flash Drive)
ISBN オンライン: 978-1-56700-496-0
Proceedings of the 25th National and 3rd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2019)
THERMOCAPILLARY MIGRATION OF WATER DROPLETS ON SUPERHYDROPHILIC SURFACES
Actuation of water droplets by thermocapillary phenomenon
is quite challenging due to typically large contact angles and the associated contact angle hysteresis. The present study demonstrates the migration of water droplets over UV treated TiO2 based superhydrophilic surfaces characterized by near 0° contact angle. This technique has a merit of migrating water droplets with moderate temperature gradients without the need for expensive microfabrication procedures and/or patterned wettability microheaters. The influence of droplet volume on the temporal evolution of the velocity is studied for 2µl and 6µl droplets. The
thermocapillary and spreading effects on water droplet migration dynamics are qualitatively explained. Further, fluid flow and heat transfer phenomena inside the droplet during migration are elucidated from emerging thermal patterns captured using infrared (IR) thermography.