| 초록 |
Polymer composites to assay the radioactive contamination were prepared using polysulfone (PSF) and cerium activated yttrium silicate (CAYS), consisting of a dense support layer and a top layer holding CAYS. The active top layer in the film was obtained by the coagulation of a casting solution via the diffusion-induced phase inversion. As coagulated through direct immersion into a water bath without vapor exposure, the CAYS-holding layer showed a typical asymmetric structure with large macropores. The inorganic fluor, CAYS, was embedded in the matrix by being transfixed into a polymer network. With the increase in vapor exposure time before immersion in a water bath, morphology of the films transformed from asymmetric to sponge-like structures, revealing more developed cellular structure. CAYS, which is separated from the polymer network, was found in the nucleated polymer-lean phase. The border structure between the two layers epitomized the phase inversion rate of a cast solution, revealing the ingredients’ movement during the structure formation. As for the film prepared by direct immersion in a water bath, a clear-cut structure on the border supports the rapid transition of the cast solution into a solid state. On the contrary, the ambiguous interface feature on the films prepared by involving vapor exposure revealed the delayed phase transition with the corresponding sponge-like structure. The polymer phase in a sponge-like structure is so dense that the deposited radionyclides could not pass the phase, consequently coming to the loss in the detection efficiency. |
