NU 2020-001
Inventors James Stoddart* Qinghui Guo
Abstract The efficient preparation of single-crystalline ionic polymers and fundamental understanding of their structure-property relationships at the molecular level remains a challenge in chemistry and materials science. Here, we describe the single crystal structure of a highly ordered polycationic polymer (polyelectrolyte) and its proton conductivity. The polyelectrolyte single crystals can be prepared on a gram-scale in quantitative yield, by taking advantage of an ultraviolet/sunlight-induced topochemical polymerization, from a tricationic monomer—a self-complementary building block possessing a preorganized conformation. A single-crystal-to-single-crystal photopolymerization was revealed unambiguously by in-situ single-crystal X-ray diffraction analysis, which was also employed to follow the progression of molecular structure from the monomer, to a partially polymerized intermediate, and, finally, to the polymer itself. Collinear polymer chains are held together tightly by multiple Coulombic interactions involving counterions to form two-dimensional lamellar sheets (1 nm in height) with subnanometer pores (5 Å). The extraordinary mechanical strength and environmental stability—in combination with its impressive proton conductivity (~ 3×10 –4 S cm –1)—endows the polymer with potential applications as a robust proton-conducting material. By marrying supramolecular chemistry with macromolecular science, this invention represents a major step towards the controlled synthesis of single-crystalline polyelectrolyte materials with perfect tacticity.
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IP Status Provisional and PCT applications have been filed.