Determination of Contact Angles of Nanosized Silica Particles by Multi-Angle Single-Wavelength Ellipsometry

Timothy N. Hunter; Graeme J. Jameson; Erica J. Wanless

doi:10.1071/CH07133

RESEARCH FRONT

Previous Next Contents Vol 60(9)

Determination of Contact Angles of Nanosized Silica Particles by Multi-Angle Single-Wavelength Ellipsometry

Timothy N. Hunter ^A ^C , Graeme J. Jameson ^A and Erica J. Wanless ^B

+ Author Affiliations

- Author Affiliations

^A Centre for Multiphase Processes, The University of Newcastle, Callaghan NSW 2308, Australia.

^B School of Environmental & Life Sciences, The University of Newcastle, Callaghan NSW 2308, Australia.

^C Corresponding author. Email: timothy.hunter@studentmail.newcastle.edu.au

Australian Journal of Chemistry 60(9) 651-655 https://doi.org/10.1071/CH07133
Submitted: 30 April 2007 Accepted: 19 June 2007 Published: 11 September 2007

Abstract

The determination of nanoparticle wettability is an area of great practical importance to materials science and engineering fields. There has been some recent interest in using spectroscopic analysis to indirectly categorize behaviour of monolayers, using the reflective and refractive properties of immersed particles. A method is developed here to calculate specific contact information for nanoparticles at an air–water interface, using single wavelength ellipsometry. A two-layer model is used that considers the refractive index of the immersed and non-immersed particle portions. Pressureâ€“area isotherms and Brewster angle images were used to confirm and categorize the nature of a packed monolayer, and ψ and Δ measurements taken of the interface. Immersion thickness was calculated and related to an equilibrium contact angle, and combined thickness data for the two layers was successfully related to the diameter of the particles.

Acknowledgements

T. Hunter would like to thank the CSIRO for additional funding on this project. The authors would also like to thank A. Nguyen for help with the ellipsometer and G. Franks for useful discussions.

References

Determination of Contact Angles of Nanosized Silica Particles by Multi-Angle Single-Wavelength Ellipsometry

Abstract

Acknowledgements

Subscriber Login