Abstract
The synthesis of polyamide films used as active layers in reverse osmosis membranes was studied by in-situ diffuse reflectance spectroscopy, Rutherford backscattering spectrometry (RBS), and atomic force microscopy (AFM). Aromatic polyamide layers were formed by interfacial polymerization on porous polysulfone supports using varying concentrations of m-phenylenediamine (MPD) in water of 0.1-100. g/L with a fixed concentration of trimesoyl chloride (TMC) in hexane of 1. g/L and varying TMC concentrations of 0.1-10. g/L with a fixed MPD concentration of 20. g/L. Polyamide growth dynamics were monitored in real-time by diffuse optical reflectance at λ=329. nm. A relationship was developed between diffuse reflectance and polyamide thickness. The diffuse reflectance data show that ~50% of the polyamide thickness is produced in <2. s for all TMC concentrations studied and for MPD concentrations >2. g/L. All studied concentrations of TMC at a fixed 20. g/L MPD concentration produced a polyamide thickness of ≈120. nm. Polyamide thickness increased from ≈10 to 110. nm with increasing concentration of MPD at 1. g/L TMC. The roughness measured by AFM increased with increasing MPD concentration but decreased with increasing TMC concentration. At MPD concentrations <0.5. g/L, polyamide does not grow on top of the polysulfone.
Original language | English (US) |
---|---|
Pages (from-to) | 71-80 |
Number of pages | 10 |
Journal | Journal of Membrane Science |
Volume | 429 |
DOIs | |
State | Published - Feb 15 2013 |
Keywords
- Atomic force microscopy (AFM)
- Diffuse reflectance spectroscopy
- Interfacial polymerization
- Polyamide
- Reverse osmosis
- Rutherford backscattering spectrometry (RBS)
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- General Materials Science
- Biochemistry
- Filtration and Separation