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Download fileSurface energy measurements of coated titanium dioxide pigment
journal contribution
posted on 2008-03-19, 17:22 authored by Boon-Cheng Lim, Noreen Thomas, I. SutherlandIn this study surface energy measurements have been carried out on titanium
dioxide pigments coated with different types of organic compound. The organic
coatings investigated were polymethylsiloxane and octyl triethoxy-silane. The level of
coating applied was increased from 0.2 up to 1.5 weight %. Contact angles were
measured using an advancing sessile drop method. To allow for the fact that
measurements were made on pressed discs of particles rather than on a perfectly flat
surface, a correction was applied to convert each measured contact angle to the true
Young’s contact angle. Surface energies were calculated from the corrected contact
angles using the Owens and Wendt equation. From the values of surface energy it was
possible to determine at what coating level the surface characteristics changed from
hydrophilic to hydrophobic and hence when complete coverage had taken place. For
both the siloxane and the silane coatings it was found that complete coating coverage
occurred at an addition level of around 0.8 weight %. The surface energies of all the
coated pigments were found to correlate well with their dispersion behaviour in liquid
paraffin.
Keywords: In this study surface energy measurements have been carried out on titanium
dioxide pigments coated with different types of organic compound. The organic
coatings investigated were polymethylsiloxane and octyl triethoxy-silane. The level of
coating applied was increased from 0.2 up to 1.5 weight %. Contact angles were
measured using an advancing sessile drop method. To allow for the fact that
measurements were made on pressed discs of particles rather than on a perfectly flat
surface, a correction was applied to convert each measured contact angle to the true
Young’s contact angle. Surface energies were calculated from the corrected contact
angles using the Owens and Wendt equation. From the values of surface energy it was
possible to determine at what coating level the surface characteristics changed from
hydrophilic to hydrophobic and hence when complete coverage had taken place. For
both the siloxane and the silane coatings it was found that complete coating coverage
occurred at an addition level of around 0.8 weight %. The surface energies of all the
coated pigments were found to correlate well with their dispersion behaviour in liquid
paraffin.
Keywords: Titanium dioxide; surface energy; contact angle; organic coating; surface energy; contact angle; organic coating
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials
Citation
LIM, B.C., THOMAS, N.L. and SUTHERLAND, I., 2007. Surface energy measurements of coated titanium dioxide pigment. Progress in organic coatings, 62 (2), pp. 123-128Publisher
© ElsevierPublication date
2008Notes
This article was published in the journal, Progress in organic coatings [© Elsevier]. The definitive version is available at: http://www.sciencedirect.com/science/journal/03009440ISSN
0300-9440Language
- en