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Nanoscale Water Contact Angle on Polytetrafluoroethylene Surfaces Characterized by Molecular Dynamics–Atomic Force Microscopy Imaging.

Authors :
Włoch, Jerzy
Terzyk, Artur P.
Wiśniewski, Marek
Kowalczyk, Piotr
Source :
Langmuir. 4/17/2018, Vol. 34 Issue 15, p4526-4534. 9p.
Publication Year :
2018

Abstract

The aim of this study is to link polytetrafluoroethylene (PTFE) surface characteristics with its wetting properties in the nanoscale. To do this using molecular dynamics (MD) simulation, three series of rough PTFE surfaces were generated by annealing and compressing and next characterized by the application of the MD version of the atomic force microscopy (AFM) method. The values of specific surface areas were additionally calculated. The TIP4P/2005 water model was used to study the wetting properties of obtained PTFE samples. The simulated water contact angle (WCA) value for the most flat (but slightly rough) sample having PTFE density is equal to 106.94°, and it is close to the value suggested for a perfect PTFE surface on the basis of experimental results. Also, the changes in the WCA with PTFE compression are in the same range as experimentally reported. The obtained MD simulation results make it possible to link, for the first time, the WCA values with the surface MD–AFM root-mean-square roughness and with the PTFE density. Finally, we show that for PTFE wetting in the nanoscale, the line tension is negligible and the Bormashenko’s equation reduces to the Cassie–Baxter (CB) model. In fact, our simulation results are close to the CB mechanism. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
07437463
Volume :
34
Issue :
15
Database :
Academic Search Index
Journal :
Langmuir
Publication Type :
Academic Journal
Accession number :
129115535
Full Text :
https://doi.org/10.1021/acs.langmuir.8b00257