The combination of conductive material and flexible material is an unavoidable problem in the preparation of flexible sensor, but uniform combination of the materials in micro- or nanostructure is difficult. Coaxial electrospinning is an effective way to realize the combination, which is very strict for the solutions and the synthesis conditions. In this paper, composite pH-sensitive sensors were developed by coaxial electrospinning of polyaniline (PANI) and polyurethane (PU) into core–shell fibers. PU improved the mechanical properties of the sensors. The mechanical properties and conductivity of the sensor can be changed through adjusting the proportion of PANI and PU. By chronopotentiometry in buffer solutions, the sensor worked linearly in the pH range of 2–7 with the sensitivity of − 60 mV/pH and pH change below 0.2 can be detected. It was also proved that the sensor can resist the influence from the changes in temperature, detection time and deformation of the sensor, ensuring the stability in pH detection. Further, by attaching to skin, our sensor showed the response to the pH of small amount of sweat on the skin surface, which suggested the possibility in wearable devices.

中文翻译：

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同轴电纺柔性 PANI//PU 纤维作为高灵敏度 pH 可穿戴传感器

导电材料与柔性材料的结合是柔性传感器制备过程中不可避免的问题，但材料在微米或纳米结构中的均匀结合是困难的。同轴静电纺丝是实现复合的有效途径，对溶液和合成条件要求非常严格。在本文中，通过将聚苯胺 (PANI) 和聚氨酯 (PU) 同轴静电纺丝成核壳纤维，开发了复合 pH 敏感传感器。PU 改善了传感器的机械性能。可以通过调整PANI和PU的比例来改变传感器的机械性能和电导率。通过缓冲溶液中的计时电位法，传感器在 2-7 的 pH 范围内线性工作，灵敏度为 − 60 mV/pH 并且可以检测到低于 0.2 的 pH 变化。还证明该传感器可以抵抗温度变化、检测时间和传感器变形的影响，保证了pH检测的稳定性。此外，通过附着在皮肤上，我们的传感器显示出对皮肤表面少量汗液的 pH 值的响应，这表明可穿戴设备的可能性。