TY - JOUR
T1 - Polymer membranes – Fractal characteristics and determination of roughness scaling exponents
AU - Johnson, Daniel
AU - Hilal, Nidal
N1 - Funding Information:
The authors would like to thank the Royal Society , United Kingdom for funding this work through a Royal Society International Collaboration Award ( IC160133 ).
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/1/15
Y1 - 2019/1/15
N2 - Surface roughness is a parameter widely reported when characterising membrane surfaces, due to its effect on membrane properties, such as fouling / biofouling and wetting. However, a surface does not have a single roughness value, rather the magnitude of measured roughness is dependent on the length scales of measurement. Here, we report findings from roughness measurements of several commercial filtration membrane surfaces using atomic force microscopy. All membranes showed self-affine behaviour at scan sizes below approximately 10 µm, where the magnitude of root mean squared roughness, Rq, was described by both the scan length and an exponential factor, H. Furthermore, we show that values of H can be obtained from power spectra of AFM images using a relatively simple approach. Using values of H and Rq obtained at a single scan size from image power spectra allowed us to estimate, within reasonable error, Rq values at other scan size, below a cross-over length. Above this crossover length roughness scaling was linear, rather than exponential for the membranes studied.
AB - Surface roughness is a parameter widely reported when characterising membrane surfaces, due to its effect on membrane properties, such as fouling / biofouling and wetting. However, a surface does not have a single roughness value, rather the magnitude of measured roughness is dependent on the length scales of measurement. Here, we report findings from roughness measurements of several commercial filtration membrane surfaces using atomic force microscopy. All membranes showed self-affine behaviour at scan sizes below approximately 10 µm, where the magnitude of root mean squared roughness, Rq, was described by both the scan length and an exponential factor, H. Furthermore, we show that values of H can be obtained from power spectra of AFM images using a relatively simple approach. Using values of H and Rq obtained at a single scan size from image power spectra allowed us to estimate, within reasonable error, Rq values at other scan size, below a cross-over length. Above this crossover length roughness scaling was linear, rather than exponential for the membranes studied.
KW - Atomic force microscopy
KW - Polymer membrane
KW - Roughness
KW - Roughness scaling
KW - Surface characterisation
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U2 - 10.1016/j.memsci.2018.10.024
DO - 10.1016/j.memsci.2018.10.024
M3 - Article
AN - SCOPUS:85055055393
VL - 570-571
SP - 9
EP - 22
JO - Jornal of Membrane Science
JF - Jornal of Membrane Science
SN - 0376-7388
ER -