Polymerization-Induced Electrostatic Self-Assembly Governed by Guanidinium Ionic Hydrogen Bonds

Polymerization-induced electrostatic self-assembly (PIESA) represents a powerful method for the scalable synthesis of polyion complex (PIC) nanoparticles with various morphologies. Previous PIESA was driven by Coulombic interactions. Yet, biomimetic multivalent interactions, e.g., ionic hydrogen bonds omnipresent in proteins and potentially enabling access to new materials, remain unexplored. Herein, we update PIESA using arginine-like full-spectrum guanidinium ionic hydrogen bonds. Kinetic studies unravel that, at guanidinium-starving n+/n- (0.84), guanidinium interactions evolve from opposite-charge (6-73% conversion) into like-charge ionic hydrogen bonds (84 to >99% conversion), leading to ultrasmall clusters (2-5 nm, at 6-84% conversion) and size-tunable large compound micelles (14-25 nm, at 90 to >99% conversion). Longer guanidinium-block length results in the transformation of charge-neutral worms to positive-charge micron-scale large-area monolayer lamellae to multilayer platelets to tubular networks to vesicular aggregates, suggesting that the like-charge ionic hydrogen bonds are strong enough to overwhelm Coulombic repulsive interactions, and thus to revolutionize our PIESA chemistry for the precision synthesis of nextgeneration nanostructured biomimetic functional materials.

Automated summary

Polymerization-induced electrostatic self-assembly (PIESA) is a powerful method for synthesizing polyion complex (PIC) nanoparticles. In this study, PIESA was updated using arginine-like full-spectrum guanidinium ionic hydrogen bonds. The results showed that guanidinium interactions could lead to nanoparticles with different morphologies. The strong effect of like-charge ionic hydrogen bonds can overcome Coulombic repulsive interactions, revolutionizing the synthesis of nanostructured biomimetic functional materials.