Lanthanide Coordinated Poly(Thioctic Acid) Materials with Enhanced Strength and Room Temperature Self-Healing Performance.

Abstract

Poly(thioctic acid) materials exhibit excellent room-temperature self-healing properties due to their dynamic disulfide-bonded supramolecular network and have been widely used in applications such as wearable devices, adhesives, and wound patches. However, the limited mechanical properties of poly(thioctic acid) materials with dynamic supramolecular networks limit their practical applications. Therefore, there is an urgent need for a low-energy-consuming and facile method to enhance their mechanical strength and maintain their room-temperature self-healing properties. Here, a novel approach is developed by introducing Eu³⁺-coordination into the copolymerization of thioctic acid (TA) and sodium thioctate (ST), forming hierarchical dynamic supramolecular networks. Copolymerization of TA and ST under mild conditions (60 °C in ethanol/water solvent) introduces stable hydrogen-bonding interactions without additional chemical cross-linkers. Further Eu³⁺-coordination increases the mechanical modulus of the films by more than 100-fold while significantly improving toughness and strength. This is attributed to the large ionic radius and high coordination number of Eu ions with carboxylates which significantly enhanced the strength of the crosslinked network. This strategy offers a novel pathway for developing supramolecular materials with an optimal balance of mechanical strength and self-repairing capabilities, advancing their potential in various applications.