Critical study of contact angle goniometry

Research output: ThesisDoctoral ThesisCollection of Articles

Abstract

In this thesis contact angle goniometry as a characterization method for solid surface wettability is critically examined. Contact angle goniometry is a powerful and versatile tool for measuring wetting properties, facilitating the study of microscale surface properties by macroscopic an optical method. The apparent ease which with contact angles can be measured have ensured its position as the golden standard of wetting characterization. Measuring meaningful contact angles and interpreting the data correctly is far from simple, however. Real solid surfaces exhibit a range of stable contact angles. Collecting meaningful data requires knowledge to recognize the contact angles which can be reproducibly measured, on how to perform the measurements in a reliable manner and on interpretation of the results. Publication I provides a method for reliable measurement of the receding contact angle. The validity of the method is evaluated both theoretically, and by a wide range of experimental evidence. Publication II proposes a growth model for the synthesis of silicone nanofilaments - a class of superhydrophobic 1-dimensional polysiloxane nanostructures. Theoretical model for pressureinduced film expansion is provided. Publication III introduces a protocol for contact angle measurements that can be applied to a wide variety of samples. Instructions on minimizing both systematic and random errors are provided, along with troubleshooting for most common problems encountered. Publication IV quantifies the error in contact angle measurement caused by misplacement of the baseline - the line between the solid and liquid/gas in the 2D-images analyzed. Special emphasis is given on the error for superhydrophobic surfaces. Publication V expands on publications IV by quantifying the error caused by the optical system used in contact angle goniometry. User error of contact angle measurements is also meas-ured.
Translated title of the contributionKontaktikulmamittauksen kriittinen tarkastelu
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Ras, Robin, Supervising Professor
Publisher
Print ISBNs978-952-64-1621-2
Electronic ISBNs978-952-64-1622-9
Publication statusPublished - 2024
MoE publication typeG5 Doctoral dissertation (article)

Keywords

  • contact angle
  • wetting
  • superhydrophobicity
  • silicone nanofilaments

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