Sheets comprising a fluorinated polymer and presenting a variable wettability with respect to a fluid as a function of pH and/or temperature

Sheets with the title behavior consist of a fluoropolymer matrix and block copolymer anchored to the matrix with a portion of the block copolymer having a hydrophilicity that is dependent on pH and temp. A typical sheet was manufd. by polymn. of 4-vinylpyridine in the presence of BlocBuilder in DMF at 115°, polymn. of Me methacrylate and styrene in the presence of the resulting macroinitiator, and impregnation of the resulting block copolymer into PVDF membrane.