(129d) Manufacturing and Remanufacturing of Ion-Mediated Polymer Assemblies, Blends and Nanostructures

Chemically dissimilar polymers are rarely miscible due to an entropy of mixing that scales as 1/N, where N is the degree of polymerization, thus, compatibilization of immiscible polymer blends is a challenge in both academic research and relevant industry. When the chain ends of distinct polymers are functionalized with reacting cation/anion groups, supramolecular block copolymer (SBCP) with ionic junctions can form in situ via “reactive blending”, leading to stabilized microdomains and suppressing macroscopic phase separation. Due to the dynamic nature of ionic bonds, SBCP self-assembly can be tuned by the ionic bond energy (h), segregation strength (χN), and chain architecture. In this work, we synthesized a library of ionic polystyrene/polydimethylsiloxane (PS/PDMS) SBCP blends that are macroscopically homogeneous but with various end group chemistries (various h), molecular weights, and architectures (diblock and triblock). Moreover, using X-ray scattering and transmission electron microscopy techniques, we have observed well-ordered lamellae produced by stronger cation-anion interactions and more swollen microphases in weakly-interacting, larger molar mass, or triblock-type SBCPs, where unbonded homopolymers swell the corresponding domain. The phase behavior of ionic SBCP has been systematically studied experimentally and by SCFT simulations, revealing that ionic interactions are a powerful tool to compatibilize immiscible blends and might be exploited in plastic waste upcycling.