Stimuli-Responsive Peptide-Based ABA-Triblock Copolymers: Unique Morphology Transitions With pH

Authors

  • Jacob G. Ray,

    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
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  • Sandeep S. Naik,

    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
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  • Emily A. Hoff,

    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
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  • Ashley J Johnson,

    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
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  • Jack T. Ly,

    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
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  • Charles P. Easterling,

    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
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  • Derek L. Patton,

    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
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  • Daniel A. Savin

    Corresponding author
    1. School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA
    • School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #5050, Hattiesburg, MS 39406, USA.
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Abstract

We report the synthesis and solution characterization of poly(L-lysine)-b-poly(propylene oxide)-b-poly(L-lysine) (KPK) triblock copolymers with high lysine weight fractions (>75 wt%). In contrast to PK diblock copolymers in this composition range, KPK triblock copolymers exhibit morphology transitions as a function of pH. Using a combination of light-scattering and microscopy techniques, we demonstrate spherical micelle-vesicle and spherical micelle-disk micelle transitions for different K fractions. We interpret these morphology changes in terms of the energy penalty associated with folding the core P block to form a spherical micelle in relation to the interfacial curvature associated with different charged states of the K block.

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