Automated Drop-on-Fiber contact angle measurement using a microrobotic platform

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Pooya Saketi, Juha Hirvonen, Yuli Lai, Christian Ganser, Christian Teichert, Joakim Järnström, Pedro Fardim, Pasi Kallio
Publication year: 2014
Journal: Nordic Pulp and Paper Research Journal
Journal acronym: NORD PULP PAP RES J
Volume number: 29
Issue number: 2
Start page: 225
End page: 231
Number of pages: 7
ISSN: 0283-2631
eISSN: 2000-0669


Measuring contact angles on single fibers enables the separation of structural factors from surface chemistry factors. Current Drop-on-Fiber (DOF) contact angle measurement methods for natural fibers generally, and for pulp/paper fibers specifically, present a number of challenges. These are manipulation and mounting of the microscale fibers, straightening natural fibers to produce repeatable axisymmetric droplet conformation, measuring the droplet volume excluding the fiber volume and also human errors due to manually performed tasks. This paper presents a novel method to measure contact angles in DOF systems and overcome the above mentioned challenges using microrobots. The proposed microrobotic platform is capable of handling natural and synthetic fibrous materials in microscale, and dispensing probe liquid droplets down to 12 nl. It measures contact angle values using computer vision and a droplet-profile-detection algorithm. It reports the contact angle values as a function of volume of the droplet. The paper validates the capabilities of the proposed platform by applying three commonly used probe liquids: deionized water, ethylene glycol and diiodomethane for measuring contact angles on glass and pulp fibers. Finally, the results are compared with a picoliter contact angle measurement approach.


Contact Angle, Drop-on-Fiber, Micromanipulation, Microrobotics, Pulp/Paper Fiber

Last updated on 2020-29-09 at 02:54