Molecular Architecture Induced Chain-Folding in Polymeric Amphiphilic Unimolecular Micelles

ORAL

Abstract

An amphiphilic star-like macromolecule (ASM) with an aliphatic core and four poly(ethylene oxide) (PEO) arms was synthesized. Its crystallization and self-assembly behaviors at different crystallization temperatures ($T_{c}$s) were characterized by synchrotron small angle X-ray scattering (SAXS). The overall $d$-spacing of alternating amorphous and crystalline lamellae almost doubled from 11.4 nm for samples quenched into liquid nitrogen to 21.0 nm for $T_{c}$ = 42 \r{ }C. Due to an insufficient arm-to-core ratio in the ASM, chain-folding was forced to occur in the arm PEO crystals, while only extended chain crystals were observed for the PEO oligomer having a molecular weight of 2000 g/mol. In the ASM, gradual transitions from almost once-folded to non-integer folded, and finally to extended chain crystals were observed with increasing $T_{c}$ from -20 \r{ }C to 42 \r{ }C.

*This work was supported by NSF CAREER awards, DMR-0348724 (LZ) and BES-9983272 (KEU).

–

Authors

  • Lei Zhu

    • Polymer Program, Institute of Material Science and Department of Chemical Engineering, University of Connecticut, Storrs, CT 06269-3136
    • Polymer Program, Institute of Materials Science and Department of Chemical Engineering, The University of Connecticut
    • Polymer Program, Institute of Materials Science and Department of Chemical Engineering, The University of Connecticut, Storrs, CT 06269-3136

  • Jianjun Miao

    • Polymer Program, Institute of Materials Science and Department of Chemical Engineering, The University of Connecticut, Storrs, CT 06269

  • Guoqiang Xu

    • Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853

  • Lu Tian

  • Kathryn Uhrich

    • Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854

  • Carlos Avila-Orta

  • Benjamin Hsiao

    • Chemistry Department, State University of New York at Stony Brook, Stony Brook, NY 11794
    • Department of Chemistry, Stony Brook University
    • Department of Chemistry, State University of New York, Stony Brook, NY 11794 - 3400
    • Stony Brook University
    • Chemistry Department, State University of New York at Stony Brook