The synthesis, molecular and morphological characterization of a 3-miktoarm star terpolymer of polystyrene (PS, M¯n = 61.0 kg/mol), polybutadiene (PB, M¯n = 38.2 kg/mol) and polyisoprene (PI, M¯n = 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.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors would like to thank Malcolm Capelfor his technical assistance at the National Synchrotron Light Source at Brookhaven National Laboratory (BNL). A.A. would like to acknowledge Christian Honeker and Sam Ha for their help in obtaining the SAXS results from BNL. A.A., D.M., G.-M.M. and A.K.-M. would like to acknowledge the Network of Research Supporting Laboratories at the University of Ioannina for using the Electron Microscopy Facility and the Nuclear Magnetic Resonance Spectroscopy Center. G.Z.,
K.N. and N.H. would like to acknowledge the support of King Abdullah University of Science and Technology (KAUST).