Effect of the number of crystallizable blocks on the lamellar crystalline structure of block copolymers from poly(4‐tert‐butylstyrene) and poly(ethylene oxide)

Abstract

AbstractLinear block copolymers tBSEO with an amorphous block of poly(4‐tert‐butylstyrene) (PtBS) and a crystallizable block of poly(ethylene oxide) (PEO) as well as branched block copolymers tBS(EO)2 with two PEO chains linked at the same end of a PtBS block exhibit a lamellar liquid‐crystalline structure in the dry state as well as in the presence of a preferential solvent of the PtBS block. In this structure the crystallized chains are folded in two superposed layers. To investigate the effect of the number of the PEO blocks, a linear and a branched copolymer with identical relative molecular masses and copositions were studied by X‐ray diffraction and differential scanning calorimetry. It was shown that the melting temperature, the degree of crystallinity, and the number of folds of the PEO chains are higher for the linear copolymer than for the branched one.