Crystallization, melting, and morphology of a poly(ethylene oxide) diblock copolymer containing a tablet-like block of poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene}

A poly(ethylene oxide) diblock copolymer containing a short block of poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PEO- b-PMPCS) has been successfully synthesized via atom transfer radical polymerization (ATRP) method. The number average molecular weights ( M n) of the PEO and PMPCS blocks are 5300 and 2100 g/mol, respectively. Combining the techniques of differential scanning calorimetry (DSC), optical microscopy (OM), wide angle X-ray diffraction (WAXD), and small angle X-ray scattering (SAXS), we have found that the PMPCS blocks, which are tablet-like, can significantly affect the crystallization and melting of the diblock copolymer. The sample studied can form the crystals with a monoclinic crystal structure identical to that of the homo-PEO. The melting temperature ( T m) of the diblock copolymer increases monotonically with crystallization temperature ( T c), which is remarkably similar to the behavior of long period. On the basis of Gibbs–Thomson relationship, the equilibrium T m ( T m 0 ) of the diblock copolymer is estimated to be 65.4 °C. In a wide undercooling (Δ T) range (14 °C