Titlebar

Export bibliographic data
Literature by the same author
plus on the publication server
plus at Google Scholar

 

Wetting on Fractal Superhydrophobic Surfaces from "Core-Shell" Particles : A Comparison of Theory and Experiment

Title data

Synytska, Alla ; Ionov, Leonid ; Grundke, Karina ; Stamm, Manfred:
Wetting on Fractal Superhydrophobic Surfaces from "Core-Shell" Particles : A Comparison of Theory and Experiment.
In: Langmuir. Vol. 25 (3 March 2009) Issue 5 . - pp. 3132-3136.
ISSN 1520-5827
DOI: https://doi.org/10.1021/la803120d

Abstract in another language

We report an experimental and theoretical investigation of the wetting behavior of different model polar and nonpolar liquids and their mixtures on superhydrophobic fractal surfaces made of polymer- or silane-coated "core-shell" particles. We compared the experimental results with the theoretical predictions made according to the theories of Onda/Shibuichi (describes wetting on fractal surfaces) and Cassie-Baxter (describes wetting on generic rough composite surfaces). We found that the experimental findings deviate from the behavior predicted by the Onda-Shibuichi model. On the other hand, the wetting properties were found to be close to the predictions made by the Cassie-Baxter model in the hydrophobic region (the intrinsic contact angle on the flat surface is larger than 90°). However, the wetting behavior in the hydrophilic region (the intrinsic contact angle is less than 90°) could not be described by the Onda-Shibuichi or Cassie-Baxter model. The observed inconsistency between the experimental results and theoretical predictions was explained by the formation of metastable states of a liquid droplet on a fabricated fractal surface according to the theory developed by Johnson and Dettre for generic rough surfaces. The entrapments of the liquid droplets in metastable states resulted in superhydrophobic behavior on fractal surfaces as well, made from nonfluorinated material such as polystyrene with a surface free energy of about 30 mJ/m2. This finding is very promising for real industrial applications where fluorinated compounds are willing to be reduced. It can be concluded that employing a texture with fractal geometry is necessary for the design of superhydrophobic coatings. Thereby, extremely lowering the surface free energy of materials by fluorination is not an obligatory factor for the generation of liquid-repellent superhydrophobic materials. We believe that the results we presented in the paper give new insight into the understanding of wetting not only on general superhydrophobic rough surfaces but also on fractal surfaces.We report an experimental and theoretical investigation of the wetting behavior of different model polar and nonpolar liquids and their mixtures on superhydrophobic fractal surfaces made of polymer- or silane-coated "core-shell"particles. We compared the experimental results with the theoretical predictions made according to the theories of Onda-Shibuichi (describes wetting on fractal surfaces) and Cassie-Baxter (describes wetting on generic rough composite surfaces). We found that the experimental findings deviate from the behavior predicted by the Onda-Shibuichi model. On the other hand, the wetting properties were found to be close to the predictions made by the Cassie-Baxter model in the hydrophobic region (the intrinsic contact angle on the flat surface is larger than 90°). However, the wetting behavior in the hydrophilic region (the intrinsic contact angle is less than 90°) could not be described by the Onda-Shibuichi or Cassie-Baxter model. The observed inconsistency between the experimental results and theoretical predictions was explained by the formation of metastable states of a liquid droplet on a fabricated fractal surface according to the theory developed by Johnson and Dettre for generic rough surfaces. The entrapments of the liquid droplets in metastable states resulted in superhydrophobic behavior on fractal surfaces as well, made from nonfluorinated material such as polystyrene with a surface free energy of about 30 mJ/m2. This finding is very promising for real industrial applications where fluorinated compounds are willing to be reduced. It can be concluded that employing a texture with fractal geometry is necessary for the design of superhydrophobic coatings. Thereby, extremely lowering the surface free energy of materials by fluorination is not an obligatory factor for the generation of liquid-repellent superhydrophobic materials. We believe that the results we presented in the paper give new insight into the understanding of wetting not only on general superhydrophobic rough surfaces but also on fractal surfaces.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Engineering Science > Professur Biofabrikation > Professur Biofabrikation - Univ.-Prof. Dr. Leonid Ionov
Faculties
Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Professur Biofabrikation
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 540 Chemistry
Date Deposited: 22 Jun 2017 11:28
Last Modified: 22 Jun 2017 11:28
URI: https://eref.uni-bayreuth.de/id/eprint/37720