|dc.description.abstract||Droplet motion is an everyday phenomenon with potential benefits to multiple
industrial and biological applications. It can be achieved via various methods,
and the understanding and altering of the underlying mechanism are
important to the accurate control of the droplet behaviour and motion. This
thesis focuses on three different mechanisms that induce the droplet motion:
roughness gradient by micro-structure fabrication, thermocapillary motion
with self-rewetting fluid and vapor-mediated droplet motion.
Firstly, the motion of microscale water droplets on the hydrophobic microstructured
surfaces with structural wettability contrast has been studied. The
velocity and displacement of the droplets moving across the wettability
contrasts have been monitored and their relations to the morphological
parameters of the micro-structure have been systematically investigated.
Besides, the dynamic behaviour of the droplets has been investigated and
explained by the mathematical mode proposed.
Secondly, the thermocapillary motion of self-rewetting droplets has been
reported. The behaviour of self-rewetting droplets departed greatly from the
droplets of ordinary mixture and pure fluids. A unique oscillatory behaviour
was observed for self-rewetting droplets, which was related to the nonmonotonic
dependence of surface tension on temperature. Influencing
parameters were studied and IR thermography assisted to reveal the internal
Last, the motion of sessile mixture or pure droplets induced by vapour was
investigated. The spatial concentration change via the mass transfer through
the liquid-vapour interface near contact line leads to unbalanced surface
tension, which leads to droplet motion. Depending on the concentration of
both droplets and the vapour, repulsive or attractive motion can be observed.
A phase map as well as a critical concentration boundary was proposed for
the mixture of PG and water droplets, which can help to predict the direction
of droplet motion.||en
|dc.publisher||The University of Edinburgh||en
|dc.title||Study of passive and active driven motion of droplets on engineered substrates||en
|dc.title.alternative||A study of passive and active driven motion of droplets on engineered substrates||en
|dc.type||Thesis or Dissertation||en
|dc.type.qualificationname||PhD Doctor of Philosophy||en