The Applicability of a Drop Penetration Method to Measure Contact Angles on TiO2 and ZnO Nanoparticles

Sabrina M Garner; Edgar A O'Rear; Sharukh Soli Khajotia; Fernando Luis Esteban Florez

doi:10.3390/nano10061099

The Applicability of a Drop Penetration Method to Measure Contact Angles on TiO₂ and ZnO Nanoparticles

Nanomaterials (Basel). 2020 Jun 2;10(6):1099. doi: 10.3390/nano10061099.

Authors

Sabrina M Garner¹, Edgar A O'Rear², Sharukh Soli Khajotia³, Fernando Luis Esteban Florez³

Affiliations

¹ Stephenson School of Biomedical Engineering, University of Oklahoma, 173 Felgar St., Norman, OK 73019, USA.
² Chemical, Biological, and Materials Engineering, IBEST, University of Oklahoma, 100 East Boyd Street, T-301, Norman, OK 73019, USA.
³ Department of Restorative Sciences, The University of Oklahoma Health Sciences Center College of Dentistry, Division of Dental Biomaterials 1201 N. Stonewall Ave., Oklahoma, OK 73117, USA.

Abstract

In this study, six solvents (water, diiodomethane, bromonaphthalene, formamide, ethanol and ethylene glycol) were examined for three nanoparticle substrates, zinc oxide and titanium dioxide (21 nm and 100 nm), with the goal of assessing the suitability of a modified drop penetration method (DPM) for orders of magnitude smaller particles. Nanoparticles were compressed into flat discs and the solvent dropped on the surface while the image with time was recorded. Contact angles were in reasonable agreement with literature over the range of 20-80°, but failed to provide acceptable results for surface energy components. It was necessary to eliminate certain solvents and substrates not meeting the selection criteria.

Keywords: contact angle measurement; drop penetration method; nanoparticle; powder; titanium dioxide; zinc oxide.