Polymer Engineering Faculty Research

Supramolecular Multiblock Polystyrene-Polyisobutylene Copolymers via Ionic Interactions

Longhe Zhang, University of Akron Main Campus
Robson F. Storey
Kevin Cavicchi, University of Akron Main Campus
Robert Weiss, University of Akron Main Campus

Abstract

Main-chain supramolecular block copolymers consist of individual blocks that are connected by non-covalent bonds. The work described here used ionic interactions as the non-covalent linkers, which provided much stronger binding energy compared to more commonly used hydrogen bonds. Two oligomeric building blocks, i.e. telechelic polystyrene end-capped with sulfonic acid (PS(SO3)2, Mn=6500Da, PDI=1.19) and telechelic polyisobutylene end-capped with primary amine (PIB(NH2)2, Mn=6200Da, PDI=1.02), were employed to prepare supramolecular multiblock copolymers (SMBCP). The SMBCP was a clear, flexible and self-standing film with a highly ordered microstructure of lamellar nanodomains, as determined by small-angle X-ray scattering (SAXS) and frequency-dependent melt rheology. An order-disorder transition (ODT) was observed using temperature dependent SAXS. Temperature sweep rheological measurements showed a plateau and ODT, which again demonstrated the formation of the high molecular weight SMBCP. The nonlinear response of the SMBCP was investigated by three strain sweep-time sweep cycles. Due to the high dissociation energy of the ionic interactions used, the supramolecular block copolymers remained intact even when large strain amplitude was applied.