Continuous conductive network is associated with the percolation effect, yet the method of fabricating network structure at low content is still a challenge. Herein, this work proposed a “honeycomb” structure via hot pressing to realize weak negative permittivity at low percolation threshold. By polydopamine (PDA) self-polymerization and silver mirror reaction plating, Ag nanoparticles coated polystyrene (PS) microsphere (PS@PDA@Ag) was prepared. Through hot pressing, the microspheres were compressed into “honeycomb”. The percolation threshold was reduced because the thin silver layer oscillated at low frequency plasma. Besides, by controlling the slivering time, weak negative permittivity in the range of −139 to −95 was observed and the percolation threshold was merely 2.23 vol%. The ac conductivity increased by four orders of magnitude and the thermal conductivity enhanced 79.08 %. The electric field and power loss density were simulated by finite element method. More than 100 V/m of electric field mode and 3 × 10 W/m of power loss density were presented, explaining the generation of negative permittivity and the enhancement of dielectric loss. This work presented a method of achieving weak negative dielectric via honeycomb structure, and provided a novel perspective for the development of metal-based metacomposites.

中文翻译：

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银纳米粒子构建的蜂窝网络结构在低渗流阈值下实现负介电常数


连续的导电网络与渗流效应相关，但低含量网络结构的制造方法仍然是一个挑战。本文提出了一种通过热压的“蜂窝”结构，以在低渗流阈值下实现弱负介电常数。通过聚多巴胺（PDA）自聚合和银镜反应电镀，制备了纳米银颗粒包覆的聚苯乙烯（PS）微球（PS@PDA@Ag）。通过热压，微球被压缩成“蜂窝”。由于薄银层在低频等离子体下振荡，渗透阈值降低。此外，通过控制划条时间，观察到在-139至-95范围内的弱负介电常数，逾渗阈值仅为2.23vol%。交流电导率提高了四个数量级，导热系数提高了79.08%。采用有限元法对电场和功率损耗密度进行了模拟。超过100 V/m的电场模式和3×10 W/m的功率损耗密度，解释了负介电常数的产生和介电损耗的增强。该工作提出了一种通过蜂窝结构实现弱负介电的方法，为金属基超复合材料的发展提供了新的视角。