Developing the inorganic piezoelectric particles/polymer matrix composites is a simple, effective, and low-cost strategy to manufacture the flexible, wearable sensors. But their application has been hindered by an obvious trade-off between electronic performances and mechanical deformability, because of the issue of dispersion difficulty and isolated distribution of inorganic nanofillers in matrix. Here, an ultra-soft, substrate-free, wearable piezoelectric sensor with aligned barium titanate (BTO) nanoparticles was designed and fabricated. To resolve the issue of degradation of flexibility of composites, a chemical etching treatment was introduced into the process of hydrothermal, which increased the content of tetragonal BTO nanoparticles and optimized the interaction between inorganic layer and polymer matrix. Thus, a higher sensitivity of 73.5 V/MPa was obtained by the as-prepared composites with the orientation of BTO than those of the reported BTO-based composites. Notably, the sensor with the thin functional layer demonstrated excellent stability even after 200 double-folded fatigue cycles. For this reason, the designed sensor could completely wrap or attach onto the different complex surface to simultaneously detect various dynamic signals involving the fluidic flowing, pulse rate and moved direction of body. Moreover, the foldable piezoelectric sensing array was easily fabricated by the proposed method, which offers the huge opportunity for the widespread applications in health monitoring, personal safety, and activity monitoring on the complex surface.

中文翻译：

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基于对准 BaTiO3 纳米颗粒的超柔软、可折叠、可穿戴压电传感器


开发无机压电粒子/聚合物基复合材料是制造柔性可穿戴传感器的一种简单、有效且低成本的策略。但由于分散困难和基质中无机纳米填料的孤立分布问题，它们的应用受到电子性能和机械变形性之间明显权衡的阻碍。在这里，设计和制造了一种超柔软、无衬底、可穿戴的压电传感器，该传感器具有对准钛酸钡 （BTO） 纳米颗粒。为解决复合材料柔韧性退化的问题，在水热工艺中引入了化学蚀刻处理，提高了四方 BTO 纳米颗粒的含量，优化了无机层与聚合物基体之间的相互作用。因此，与已报道的基于 BTO 的复合材料相比，具有 BTO 取向的复合材料获得了更高的灵敏度，为 73.5 V/MPa。值得注意的是，具有薄功能层的传感器即使在 200 次双折疲劳循环后也表现出出色的稳定性。因此，所设计的传感器可以完全包裹或附着在不同的复杂表面上，以同时检测涉及流体流动、脉搏速率和物体移动方向的各种动态信号。此外，所提出的方法很容易制造出可折叠的压电传感阵列，这为复杂表面上的健康监测、人身安全和活动监测的广泛应用提供了巨大的机会。