Few solvents are capable of dissolving polyketones (PKs). 1,1,1,3,3,3-Hexafluoro-2-propanol (hexafluoroisopropanol, HFIP) is a better solvent than trifluoroethanol and m-cresol. When HFIP was evaporated from a PK/HFIP solution, a porous cast-film with a microparticle structure was formed because the isotactic PKs adopted a helical conformation, and convection during evaporation of the high polarity and low-boiling-point HFIP caused aggregation and rolling of the polymer molecules. The addition of plasticizer suppressed particle formation, improving the surface structure and mechanical properties of the film. In particular, the dielectric properties of the film improved significantly. This will enable PKs, which are rigid insulating materials, to be used as dielectric materials, broadening their range of applications. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 887-892