高强度各向异性导电复合薄膜材料

High-strength anisotropic conductive composite film materials

  • 摘要: 随着柔性电子与智能器件的快速发展,各向异性导电材料因其方向选择性电荷传输特性,在传感、能量储存及电磁屏蔽领域展现出重要应用潜力。然而,现有制备方法普遍依赖外场诱导,制备工艺复杂,存在取向性不足、导电填料团聚等结构缺陷,导致导电网络连续性与力学稳定性受限。针对上述挑战,本工作提出了一种基于超铺展诱导取向与限域聚合相结合的策略,以蒙脱土(MMT)纳米片为骨架、聚吡咯(PPy)为导电相,构筑高强度各向异性导电薄膜材料。首先利用超铺展过程中产生的界面剪切液流诱导MMT纳米片取向排列,构筑有序层状骨架;随后在取向纳米片层间进行吡咯单体限域原位聚合,使PPy在受限空间内形成连续导电网络。所制备的复合薄膜拉伸强度高达306.03 ± 15.21 MPa,水平方向电导率达到3.15 ± 0.28 S·cm−1,远高于垂直方向1.55 ± 0.12×10-5 S·cm−1。该体系为构筑高性能、多功能的各向异性导电材料提供了新的设计思路。

     

    Abstract: 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.

     

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