A novel strategy for designing high-performance self-healing polysiloxane-polyurea composites enhanced by dopamine-grafted cellulose nanofibers and Zn2+

Inspired by natural mussels, a novel dopamine-grafted cellulose nanofiber (DA-CNF) functional filler and Zn²⁺ were incorporated into polysiloxane-polyurea to create advanced composites for Internet of Things applications. Through experimental characterization, molecular dynamics (MD) simulations and finite element (FE) analysis, we thoroughly investigated the mechanism by which DA-CNF and Zn²⁺ improve the mechanical and self-healing properties of the polymer. The innovative synergistic effect of extra-added dynamic hydrogen bonds and metal ion coordination bonds between the filler and matrix simultaneously enhanced mechanical strength and self-healing efficiency, overcoming the traditional trade-off problem in conventional polymers. The results showed that the tensile strength and healing efficiency of DA-CNF/PU@Zn²⁺ were 198.89 % and 104.77 % of the value of the control sample, respectively. This performance significantly surpasses that of previously reported self-healing polydimethylsiloxane-based materials. In the EMI shielding tests for Internet of Things applications, the conductive composite film fabricated with DA-CNF/PU@Zn²⁺ and silver nanowires (AgNWs) effectively addresses the issues of resource waste and device stability. These findings offer a new strategy for designing high-performance self-healing composite materials with significant potential for applications in electronics, aerospace, automotive and wearable devices.