Construction of Supramolecular Polymer Networks Regulated by Dynamic Covalent Chemistry and Optimization of Their Self-Healing Properties

Abstract

This study focuses on the design, synthesis, and characterization of a novel class of supramolecular polymer networks (SPNs) whose architecture and dynamics are precisely regulated by dynamic covalent chemistry (DCC). The integration of dynamic covalent bonds, specifically reversible imine bonds, within a flexible poly(ethylene glycol) (PEG)-based network backbone aims to create materials that synergistically combine robust mechanical properties with efficient self-healing capabilities. The networks were constructed via a one-pot condensation reaction between a difunctional PEG-diamine and a trifunctional aldehyde, benzene-1,3,5-tricarbaldehyde. By systematically varying the stoichiometric ratio between the amine and aldehyde functional groups, as well as the molecular weight of the PEG-diamine, a series of networks with tunable crosslink density and dynamics were obtained. The structural integrity, thermal properties, and viscoelastic behavior of the resulting materials were thoroughly investigated using Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The self-healing performance was quantitatively evaluated through macroscopic damage-repair experiments and the recovery of mechanical properties, including tensile strength and fracture strain. The results demonstrate that an optimal balance between network stability and bond exchange kinetics is crucial for achieving autonomous self-healing at mild conditions without external intervention. Networks with moderate crosslink density exhibited the most promising performance, showcasing high healing efficiency (> 92% recovery in tensile strength after 12 hours at 50°C) while maintaining adequate structural integrity. This work provides fundamental insights into the structure-property relationships in DCC-regulated SPNs and outlines a versatile strategy for fabricating advanced self-healing polymeric materials for applications in soft robotics, wearable electronics, and sustainable coatings.