Polymer nanocomposites with nanoparticles dispersed in polymer matrices have attracted extensive attention due to their significantly improved overall performance, in which the nanoparticle-polymer interface plays a key role. Understanding the structures and properties of the interfacial region, however, remains a major challenge for polymer nanocomposites. Here, we directly observe the presence of two interfacial polymer layers around a nanoparticle in polar polymers, i.e., an inner bound polar layer (~10 nm thick) with aligned dipoles and an outer polar layer (over 100 nm thick) with randomly orientated dipoles. Our results reveal that the impacts of the local nanoparticle surface potential and interparticle distance on molecular dipoles induce interfacial polymer layers with different polar molecular conformations from the bulk polymer. The bilayer interfacial features lead to an exceptional enhancement in polarity-related properties of polymer nanocomposites at ultralow nanoparticle loadings. By maximizing the contribution of inner bound polar layer via a nanolamination design, we achieve an ultrahigh dielectric energy storage density of 86 J/cm³, far superior to state-of-the-art polymers and nanocomposites.

纳米颗粒分散在聚合物基体中的聚合物纳米复合材料因其显着改善的整体性能而受到广泛关注，其中纳米颗粒-聚合物界面起着关键作用。然而，了解界面区域的结构和性能仍然是聚合物纳米复合材料的主要挑战。在这里，我们直接观察到极性聚合物中纳米粒子周围存在两个界面聚合物层，即具有对齐偶极子的内束缚极性层（约10 nm厚）和具有随机取向偶极子的外极性层（超过100 nm厚） 。我们的结果表明，局部纳米颗粒表面电势和颗粒间距离对分子偶极子的影响会导致界面聚合物层具有与本体聚合物不同的极性分子构象。双层界面特征使得聚合物纳米复合材料在超低纳米颗粒负载量下的极性相关性能得到显着增强。通过纳米层压设计最大化内结合极性层的贡献，我们实现了 86 J/cm ³的超高介电储能密度，远远优于最先进的聚合物和纳米复合材料。