Supported reagents—preparation analysis and applications. J. H. Clark,A. P. Kybett and D. J. Macquarrie. VCH,Weinheim, New York,Basle, Cambridge, 1992. pp. xi+152, price £40.50, DM108.00. ISBN 3-527-28043-X/1-56081-010-6

It is shown quantitatively that the formation of holes through the skin of membranes, prepared by the quick immersion in water of polyetherimides in solution in N-methylpyrrolidone, is governed by the solvent mobility. The surface pattern observed by videomicroscopy exhibits a characteristic distance between neighbouring holes (?5 μm) which is a linear function of D^?1_s; D_s is the solvent diffusion coefficient in the polymeric solution, measured using a pulsedfield gradient NMR technique. The dependence of this distance on the solvent concentration in water is also characterized.