Microporous solids made by polymerizing the organic phase of bicontinuous microemulsions stabilized with didodecyldimethylammonium bromide show surface areas as high as 70 m(2)/g. Small-angle X-ray scattering measurements on microporous copolymers containing polymethylmethacrylate show that these areas result from structures larger than 250 Angstrom that are generated during polymerisation. These X-rays measurements also show that the 17-Angstrom structures characteristics of the original microemulsion are retained during polymerization, but destroyed when the detergent is extracted and the solid is dried.