Synthesis and characterization of novel segmented polyionenes based on polydimethylsiloxane soft segments

Novel polydimethylsiloxane (PDMS) based polyionenes were synthesized by a modified Menschutkin reaction involving reaction between bromo-terminated PDMS oligomers and various ditertiary amino compounds. In this study, the nature of the hard segment was varied by using various ditertiary amino compounds and in some cases by incorporating chain extenders, while the soft segment content was varied by changing the molecular weight of the PDMS oligomers. The mechanical properties of these materials were found to be dependent on both the nature and amount of the hard segments. These materials also showed distinct evidence of a microphase-separated morphology where under normal conditions, the hard segments formed in what are believed to be cylindrical ion-rich microdomains dispersed randomly in the soft PDMS matrix. When subjected to uniaxial deformation, the ionic cylinders were found to orient along their long axes in the stretch direction.