Alternating Gyroid Network Structure in an ABC Miktoarm Terpolymer Comprised of Polystyrene and Two Polydienes.

Dimitrios Moschovas,George Zapsas,Nikolaos E Zafeiropoulos,Dimitri A Ivanov,Andreas Karydis-Messinis,Konstantinos Ntetsikas,Alexey A Piryazev,Gkreti-Maria Manesi,Nikos Hadjichristidis,Edwin L Thomas,Apostolos Avgeropoulos

doi:10.3390/nano10081497

Abstract

The synthesis, molecular and morphological characterization of a 3-miktoarm star terpolymer of polystyrene (PS, = 61.0 kg/mol), polybutadiene (PB, = 38.2 kg/mol) and polyisoprene (PI, = 29.2 kg/mol), corresponding to volume fractions (φ) of 0.46, 0.31 and 0.23 respectively, was studied. The major difference of the present material from previous ABC miktoarm stars (which is a star architecture bearing three different segments, all connected to a single junction point) with the same block components is the high 3,4-microstructure (55%) of the PI chains. The interaction parameter and the degree of polymerization of the two polydienes is sufficiently positive to create a three-phase microdomain structure as evidenced by differential scanning calorimetry and transmission electron microscopy (TEM). These results in combination with small-angle X-ray scattering (SAXS) and birefringence experiments suggest a cubic tricontinuous network structure, based on the I4132 space group never reported previously for such an architecture.

Highlights

ABC linear triblockterpolymers consist of two-junction points connecting the two end-blocks (A and C) to the center block (B), whereas for ABC miktoarm stars a single central junction point joins the three different arms [1,2,3,4,5,6,7,8,9,10,11,12]
We report the synthesis and the structural characterization of a new three-miktoarm star terpolymer consisting of PS, 1,4-PB and high 3,4-PI
All purification procedures for monomers, solvents and initiator to the standards required for anionic polymerization have been described in detail elsewhere [47,53]

Summary

Introduction

ABC linear triblockterpolymers consist of two-junction points connecting the two end-blocks (A and C) to the center block (B), whereas for ABC miktoarm stars a single central junction point joins the three different arms [1,2,3,4,5,6,7,8,9,10,11,12]. Matsushita et al [37] studied a large number of miktoarm star terpolymers of the (PI)(PS)(P2VP) type and terpolymer/homopolymer blends, which indicated various periodic tiling patterns consisting of polygons, core-shell-type topologies, three-phase component structures, cubic networks, etc., trying to cover a large range of possible volume fraction combinations. Within their extensive study, they have assigned one of the observed microstructures of a (PI)(PS)(P2VP) terpolymer blended with PS homopolymer in the zinc blende type structure with a 45 mm lattice constant, which is a non closed packed structure impossible to be achieved by using linear triblock terpolymers [38].

Materials and Methods

Results and Discussion

Conclus2ions 3