High-strength anisotropic conductive composite film materials

With the rapid development of flexible electronics and intelligent devices, anisotropic conductive materials have demonstrated significant potential in sensing, energy storage, and electromagnetic interference (EMI) shielding due to their direction-selective charge transport properties. However, existing fabrication methods generally rely on external-field induction and involve complex processing procedures, often leading to structural issues such as insufficient orientation control and aggregation of conductive fillers. These limitations hinder the formation of continuous conductive networks and compromise mechanical stability. To address these challenges, this work proposes a strategy that integrates superspreading-induced alignment with confined polymerization. Using montmorillonite nanosheets as the structural scaffold and polypyrrole as the conductive phase, a high-strength anisotropic conductive film is constructed. First, interfacial shear flow generated during the superspreading process is employed to induce the oriented assembly of MMT nanosheets, thereby forming an ordered layered framework. Subsequently, pyrrole monomers are polymerized in situ within the confined spaces of the oriented nanosheets, enabling PPy to form a continuous conductive network under spatial confinement. The resulting composite film exhibits an ultrahigh tensile strength of 306.03 ± 15.21 MPa. Moreover, the in-plane electrical conductivity reaches 3.15 ± 0.28 S·cm⁻¹, which is several orders of magnitude higher than that in the through-thickness direction (1.55 ± 0.12 × 10⁻⁵ S·cm⁻¹). This method provides a new design strategy for developing high-performance, multifunctional anisotropic conductive materials.