Measurement of Contact Angle and Wetting Properties

Measurement of Contact Angle and Wetting Properties
John A. STUDENT, B. Supervisor* and C. Staff
Department of Mechanical Engineering, Curtin University, Perth, WA 6845, Australia
*Company Name, Company Address
E-mail: [e-mail]
ABSTRACT
This study is on the various techniques that are mostly usable in the measurements of the contact
angles among them the conversational telescope-goniometer method, the drop-shape analysis methods
that were recently developed and the Wilhemy balance method. Elaborate applications and limitations
of each of the methods are described. Concern is also attached to exploration on ultra-small droplets
on solid surfaces allowing the testing of the wetting theories down to the manometer scale. This brings
new insights into the phenomena of contact angle and wetting behaviour.
INTRODUCTION
The topic wetting has attracted a lot of interest and attention both from the applied and fundamental
perceptions due to its numerous applications in the industrial processes. Wettability studies include
taking measurements of contact angles as the primary data which is illustrative of the extent of
wetting when a solid comes into contacts with a liquid. Large contact angles mean low wettability
while small contact angles mean high wettability1. The fundamentals of the basic science behind
wetting and contact angle is given an in depth discussion in this chapter as well as an elaborate
discussion on the different techniques used in measuring angles. Direct and indirect force methods are
the most common classifications of the techniques. Calculations are done based on the values of
contact angle-the surface tension of the solid, which is used in the determination of the wetting
characteristics of the solid.
RESULTS AND DISCUSSION
The first graph was an illustration of how temperature changes with changes in the length of time for
the two thermocouples: left and right thermocouples. Another graph introduced is one on the average
temperature of the surface2. As can be observed from the graphs, the temperature increases with an
increase in the length of the time. As time increases, the thermocouples gains more kinetic energy in
its particles thereby leading to increased rate of vibration of the particles and hence an increase in the
temperature with time.