| abstract |
An ultrathin polymeric membrane has a membrane thickness of 10 to 1,000 Å. The membrane is constituted of polycarboxylate and obtained by the spin coating method or by the Langmuir-Blodgett method. The polycarboxylate contains recurrent units represented by the formula (I)n wherein R₁ and R₂ represent different groups and each stand for a methyl group or a hydrogen atom, and R represents a hydrocarbon group selected from the group consisting of a branched alkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a substituted alkyl group having 2 to 6 carbon atoms, a substituted cycloalkyl group having 3 to 10 carbon atoms and a siloxanic hydrocarbon group. |