Atomic force microscopy characterization of ultrafiltration membranes: correspondence between surface pore dimensions and molecular weight cut-off

• Published in: Surface and interface analysis Vol. 29; no. 8; pp. 544 - 547
• Main Authors: Richard Bowen, W., Doneva, Teodora A.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.08.2000; Wiley
• Subjects: Applied sciences; atomic force microscopy; Chemistry; Colloidal state and disperse state; Exact sciences and technology; Exchange resins and membranes; Forms of application and semi-finished materials; General and physical chemistry; Membranes; molecular weight cut-off; Polymer industry, paints, wood; pore size; Technology of polymers; ultrafiltration membrane; Atomic force microscopy; Membrane; Pore size; Property structure relationship; Ultrafiltration; Molecular weight
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/1096-9918(200008)29:8<544::AID-SIA901>3.0.CO;2-4

Atomic force microscopy (AFM) has been used to quantify the mean surface pore diameters of a family of five ultrafiltration membranes with molecular weight cut‐off (MWCO) in the range 1000–10 000 aspect ratio tips were used and the images were treated with fast Fourier transform filtering to remove distortions. The mean pore diameters were found to be in the range 1.93–3.14 nm, increasing systematically with the MWCO. Mean pore diameters have also been evaluated from the MWCO values using three published expressions relating MWCO to solute radius. Depending on the expression used, the ratio of the mean pore diameters obtained from MWCO data and AFM measurements (Rr) was in the range 1.04–2.42. Agreement between the diameters obtained in the two ways was best for the membranes with the lowest MWCO values. The overall agreement was substantially better than has been reported previously. The good correspondence between mean surface pore dimensions and MWCO demonstrates the usefulness of AFM in quantifying such a key membrane property. Copyright © 2000 John Wiley & Sons, Ltd.