Porous and expanded poly(tetrafluoroethy1ene) (pPTFE and ePTFE) films grafted with methacrylic acid (MAA) and 2-(dimethy1amino)ethyl methacrylate (DMA) were prepared by the combined use of the plasma treatment and photografting. Their membrane properties and permeation behavior to saccharides and dextrans were investigated. Water absorptivity and electrical conductivity considerably increased around the grafted amounts at which the individual grafted polymer chains reached the center of each PTFE film. The glucose permeability of all four types of grafted pPTFE and ePTFE films showed the maximum values at pH 8, and grafted ePTFE films had higher permeabilities than grafted pPTFE films. It was made clear from the viscometric measurements of the aqueous solutions of polyMAA (PMAA) and polyDMA (PDMA) that the glucose permeability of MAA-grafted pPTFE (MAA-g-pPTFE) and MAA-grafted ePTFE (MAA-g-ePTFE) films increased more as grafted PMAA chains expanded. Those of DMA-grafted pPTFE (DMA-g-pPTFE) and DMA-grafted ePTFE (DMA-g-ePTFE) films increased more as grafted PDMA chains contracted. These results explain that the glucose permeability of the grafted pPTFE and ePTFE films depend not only on the grafted amount but also on the distribution of the corresponding grafted polymer chains in the direction of depth inside both PTFE films. The on-off regulation of permeation for DMA-g-pPTFE and DMA-g-ePTFE films could be repeated in response to the alternate temperature change and their on-off regulation patterns were completely opposite to those of many other hydrogel samples consisting of thermosensitive polymers with lower critical solution temperatures. In addition, it was found from permeation experiments, using three types of saccharides and dextrans with different molecular weights as a permeant, that permeation flux of DMA-g-ePTFE films decreased with an increase in molecular weight of the permeant. Separation factors showed the maximum value at the grafted amount of 0.8 mmol/g. The tensile strength measurement.s showed the grafted pPTFE and ePTFE films possessed adequate strength in the waterswollen state to be of use for a functional membrane. DMA-g-ePTFE films are most suitable for a separation membrane of polymeric species of four grafted PTFE films. 0 1996