Abstract: The relationship between the compatibility in bulk and surface enrichment of PDMS has been studied with a series of [PSF-PDMS-PHS]n /PSF blends, where PSF polysulfone, PDMS polydimethylsiloxane, PHS poly-p-hydroxystyrene. DSC, DMA and TEM were used to characterize the bulk morphology, and XPS was used to obtain the information of the surface composition. It is shown that the level of surface enrichment of PDMS was affected by the compatibility between the homopolymer PSF and the hard phase of [PSF-PDMS-PHS]n. PDMS surface enrichment in the blends was similar to that in the corresponding ternary segmented copolymer [PSF-PDMS-PHS]n, when the homopolymer PSF and the hard phase of [PSF-PDMS-PHS]n were miscible. XPS results on the immiscible blends of [PSF-PDMS-PHS]n /PSF indicated a higher surface enrichment of PDMS, and the latter increased rapidly when the bulk siloxane concentrztion increased from 1% to 5%.

Key words: blend compatibility, surface enrichment, polysulfone, polydimethyl siloxane, polyhydroxy styrene