An XPS study was performed on films of methacrylic acid-styrene block copolymers (PMAA-b-PS) which were cast from DMF solutions

without or with subsequent solvent treatment. The results showed that the bulk compositions of the block copolymers had little

if any

influence on the surface compositions of the films. Direct casting from DMF solutions resulted in the highest fractional area coverages of PMAA at the surfaces according to a two-phase model

reaching a value of 0.55. In the cases of solvent treatment

the surface compositions were basically dependent on the solubility parameters of the solvents used and the fractional area coverages of PMAA at surfaces decreased in the order of water>ethyl alcohol>cyclohexane>petroleum ether.