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The structure and morphology of the skin of polyethersulfone ultrafiltration membranes: A comparative atomic force microscope and scanning electron microscope study
Author(s) -
Fritzsche A. K.,
Arevalo A. R.,
Connolly A. F.,
Moore M. D.,
Elings V.,
Wu C. M.
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070451109
Subject(s) - scanning electron microscope , ultrafiltration (renal) , membrane , materials science , chemical engineering , morphology (biology) , atomic force microscopy , coating , analytical chemistry (journal) , chemistry , nanotechnology , chromatography , composite material , biochemistry , biology , engineering , genetics
Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were used to investigate the surface structure and morphology of 10,000, 30,000, and 100,000 dalton molecular weight cutoff (MWCO) polyethersulfone (PES) ultrafiltration membranes, and the results are compared. Although both approaches reveal the pore structure in the 30,000 and 100,000 MWCO membranes, the pore diameters derived from SEM are smaller than those measured by AFM. This discrepancy is a result of the diminution in pore dimensions during the sample preparation for SEM, that is, the solvent exchange procedure needed to remove the water from the membrane prior to the high vacuum gold coating deposition step. In contrast to SEM, which requires a high vacuum both during heavy metal coating and during examination, AFM can be performed on wet ultrafiltration membranes. Consequently, the potential of altering the membranes' pore structures during sample preparation is eliminated. Therefore, the pore diameters obtained from AFM are more accurate than those derived from SEM.