Bi-layer structure formed in acrylate copolymer/fluoro-copolymer blend

Poly(2-ethylhexyl acrylate-co-acrylic acid-co-vinyl acetate), P(2EHA-AA-VAc)/poly(vinylidene fluoride-co-hexafluoro acetone), P(VDF-HFA) (70/30) blend was prepared by coating from THF solution onto poly(tetrafluoro ethylene), PTFE film. The cross-sectional layer of the P(2EHA-AA-VAc)/P(VDF-HFA) (70/30) blend revealed bi-layer structure. The P(2EHA-AA-VAc) layer and the P(VDF-HFA) layer were formed at the surface side (in contact with air) and bottom side (in contact with PTFE), respectively. We considered that the affinity between P(VDF-HFA) and PTFE strongly influenced the form of this characteristic bi-layer structure. Probe tack value of (70/30) blend reflected the form of bi-layer structure.