Incorporation of PPE in lamellar self-assembled PS-b-P4VP(PDP) supramolecules and PS-b-P4VP diblock copolymers

Self- assembled blends of PS-b-P4VP( PDP) supramolecules, obtained by hydrogen bonding of pentadecylphenol ( PDP) side chains to poly(4-vinylpyridine), and poly( 2,6- dimethyl- 1,4- diphenyl oxide) ( PPE) were investigated by thermal analysis and small- angle X- ray scattering ( SAXS) and compared with blends of PS- b- P4VP and PPE. Differential scanning calorimetry ( DSC) measurements showed a single composition dependent Tg of the PPE/ PS layers for both systems, demonstrating that PPE is distributed throughout the PS layers. Furthermore, DSC showed that for the PPE/ PS- b- P4VP( PDP) blends the presence of PDP is not restricted to the P4VP layers. Its partial presence in the PS- containing domains was confirmed by nuclear magnetic resonance ( NMR) spectroscopy on PS- P4VP core- corona nanorods prepared from hexagonally self- assembled PS- b- P4VP( PDP) supramolecules. The results of the SAXS study on the dependence of the lamellar period of PPE/ PS- bP4VP blends on the amount of PPE were in excellent agreement with a theoretical model based on the AlexanderDe Gennes approximation assuming a uniform distribution of PPE throughout the PS layers. For PPE/ PS- bP4VP( PDP) blends the dependence of the long period on the amount of PPE turned out to be somewhat stronger, which may be related to the supramolecular comb- shaped nature of the P4VP( PDP) blocks.