STUDY OF FACTORS AFFECTING THE FORMATION OF A GRADIENT STRUCTURE IN ACRYLATE COPOLYMER FLUORO-COPOLYMER BLENDS

The effects of the solution concentration and the rate of solvent evap oration on the formation of gradient structures were examined for poly (2-ethylhexyl acrylate-co-acrylic acid-co-vinyl acetate) [P(2EHA-AA-VA c)]/poly(vinylidene fluoride-co-hexafluoro-acetone) [P(VDF-HFA)] blend s. When the 30/70 P(2EHA-AA-VAc)/P(VDF-HFA) blend was prepared from 10 wt%. THF solution, a gradient structure was not formed. When the 70/3 0, 50/50, and 30/70 P(2EHA-AA-VAc)/P(VDF-HFA) blends were prepared by casting from 5 wt% tetrahydrofuran (THF) solution onto poly(tetrafluor oethylene) (PTFE), the chemical compositions of the surface and bottom sides of the blends were different depending on the blend ratio and r ate of solvent evaporation. Therefore. it was concluded that the forma tion of a gradient structure is strongly influenced by the solution co ncentration and the rate of solvent evaporation.