Highly Viscoelastic Supramolecular Polymers of Pt(II) Complexes with Exceptional Mechanical Reinforcement

초록

Controlling the mechanical properties of supramolecular polymers remains a major challenge, yet it is crucial for expanding their applicability across diverse fields. Here, we report dramatically enhanced viscosity and mechanical strength in supramolecular polymers derived from monoalkynylplatinum(II) terpyridine complexes in a 15% H2O/DMSO mixture. Remarkably, a well-dispersed supramolecular solution (1.0 mM) gradually transformed into a gel-like state with a viscosity comparable to honey. The viscoelastic properties of the resulting lamellar supramolecular polymers exhibited an approximately 7- to 90-fold increase compared to the initial state. Furthermore, the viscosity could be precisely tuned using a seeded living supramolecular polymerization strategy. High-resolution atomic force microscopy (AFM) combined with force-distance (F-D) curve analysis revealed that the Young's modulus of a single fiber reached the GPa scale upon aging, surpassing that of collagen and representing nearly a 10-fold enhancement relative to its initial value. In addition, a free-standing film fabricated solely from the highly viscoelastic supramolecular polymer, without any additives, exhibited both circular dichroism (CD) and circularly polarized luminescence (CPL), underscoring its unique multifunctional properties. These findings highlight a promising strategy for designing supramolecular materials that combine mechanical robustness with advanced optical functions.

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