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Phase‐inversion membranes. Characterisation of patterns of skin holes
Author(s) -
Addad JeanPierre Cohen,
PedroBom Ricardo
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021961115
Subject(s) - polyetherimide , membrane , phase inversion , polymer , quadrilateral , materials science , polymer chemistry , phase (matter) , chemistry , thermodynamics , composite material , physics , organic chemistry , biochemistry , finite element method
The statistical structure of the two‐dimensional random pattern of holes which are formed through the skin of phase‐inversion membranes is analysed. Membranes were prepared from a polyetherimide solved in N ‐methyl‐2‐pyrrolidone; solutions were quickly immersed in water, at room temperature. The random pattern was observed with videomicroscopy; it is shown that it can be described quantitatively from the analysis of the ensemble of all quadrilaterals drawn from nearest neighbouring holes. Perimeters and areas of quadrilaterals were found to obey a log‐normal probability distribution function. Several features characterize the random pattern of holes. (i) There is a characteristic minimum distance between nearest neighboring holes; its order of magnitude is 5 μm. (ii) This distance is shortened when the polymer concentration in the casting solution is increased. (iii) This distance is lengthened when the solvent concentration in the coagulation bath is increased.