Composition dependence of nanophase‐separated structures formed by star‐shaped terpolymers of the A_1.0B_1.0C_<i>X</i> type

Abstract

Abstract Several hierarchical nanophase‐separated structures have been observed for a series of ABC star‐shaped terpolymers by transmission electron microscopy (TEM) and electron computerized tomography (3D‐TEM). The seven terpolymers synthesized are composed of polyisoprene (I), polystyrene (S), and poly(2‐vinylpyridine) (P), their volume fraction ratios of I:S:P are 1:1: X , where X equals 0.2, 0.4, 0.7, 1.2, 1.9, 3.0, and 4.9, respectively, and additional four samples were prepared by blending each two parent terpolymers. From morphological observation by TEM and tomography, a terpolymer with X of 0.2 shows lamellar structure with spheres at the interface, those with X ranging from 0.4 to 1.9 show cylindrical structures with two‐dimensional tiling, while those with X of 3.0 and 4.9 show hierarchical cylinders‐in‐lamella structure. Two the other terpolymer samples with X of 7.9 and 10 were produced by blending a P homopolymer with the terpolymer I 1.0 S 1.0 P 4.9 , and they both exhibited columnar piled disk cylinders in P matrix. From the comparison of the present results with the predictions by the Monte–Carlo simulation, it was confirmed that the observed nanophase‐separated structures of the ISP star‐shaped terpolymers are mostly in good agreement with the prediction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2277–2283, 2007