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Surface orientation of hydrophilic groups in sulfonated poly(ether ether ketone) membranes
Chenfeng He1, Michael D Guiver, Frej Mighri
1Department of Chemical Engineering, Laval University, 1065 avenue de la Medecine, Quebec, Quebec G1V 0A6, Canada.
Journal of Colloid and Interface Science
|August 28, 2013
Summary
Sulfonated poly(ether ether ketone) (SPEEK) membranes exhibit tunable surface properties. Their surface behavior, whether hydrophobic or hydrophilic, depends on fabrication and processing conditions, impacting material performance.
Area of Science:
- Polymer Science
- Materials Science
- Surface Chemistry
Background:
- Sulfonated poly(ether ether ketone) (SPEEK) is a promising material for various applications due to its chemical and thermal stability.
- Understanding and controlling the surface properties of SPEEK membranes is crucial for optimizing their performance in different environments.
- The inherent amphiphilicity of sulfonated polymers can lead to complex surface behaviors.
Purpose of the Study:
- To synthesize SPEEK copolymers with varying sulfonate content (SC).
- To investigate the surface behavior of SPEEK membranes fabricated via solvent casting.
- To correlate surface properties with fabrication parameters and chemical structure.
Main Methods:
- Nucleophilic substitution polycondensation for SPEEK synthesis.
- Solvent casting from dimethylacetamide for membrane fabrication.
- Water contact angle measurements (sessile drop), angle-dependent X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) for surface analysis.
Main Results:
- SPEEK membranes displayed a transition from hydrophobic in air to hydrophilic in water.
- Surface analysis revealed differences between the top and bottom surfaces, with higher sulfur content on the bottom.
- The concentration of hydrophilic sulfonic groups decreased towards the membrane surface.
- Acidification and higher temperatures led to more hydrophilic surfaces.
Conclusions:
- The surface behavior of SPEEK membranes is significantly influenced by the fabrication process and post-treatment.
- The distribution of sulfonic acid groups within the membrane dictates its surface wettability.
- SPEEK membranes offer tunable surface properties for tailored applications.
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