456151 Complexation of Zwitterionic Polyelectrolyte and Inorganic Nanocluster Macroion into Mechanically Strong Supramolecular Coacervate and Hydrogel

Tuesday, November 15, 2016: 4:15 PM
Golden Gate 2 (Hilton San Francisco Union Square)
Benxin Jing, Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI and Yingxi Elaine Zhu, Chemical Engineering and Materials Science, Wayne State University, Detroit, MI

Complexation of polyanions and polycations has been investigated as the self-assembly of responsive polymeric materials ranging from layer-by-layer polymer thin films to polyelectrolyte complex coacervates and hydrogels. Instead of using two oppositely charged polyelectrolytes in salt solutions, we explore the coacervation of anionic tungsten oxide-based polyoxometalate (POM) macroions and zwitterionic polybetaine polyelectrolytes in LiCl salt solutions. The phase diagram of POM-polybetaine complexes is examined with varied POM-to-polybataine charge ratio and LiCl concentration. We are intrigued to observe a solution-coacervate-hydrogel transition as increasing POM-to-polybetaine charge ratios and broader coacervation region as increasing LiCl concentration. Importantly, the organic-inorganic macroion complexes in solution exhibit much enhanced viscoelastic properties with tunable temperature response in comparison to polyelectrolyte complexes. Bulk POM-polybetaine coacervates exhibit intriguing shear-thickening response, yet the polymer-rich liquid coacervates exhibit similar viscoelastic solid-like properties to those of the hydrogels formed at high POM-to-polybataine charge ratios. Zeta-potential and solution conductivity measurements suggest Li-cation medicated ion pairing between both net negatively charged polybetaine and POMs. The organic-inorganic macroion coacervation could open new material opportunities in controlling charge-driven phase behavior and polyelectrolyte assembly.

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See more of this Session: Nanoscale Phenomena in Macromolecular Systems
See more of this Group/Topical: Materials Engineering and Sciences Division