It is a challenge to fabricate low-cost and flexible electronic devices with degradable materials. In this work, a flexible and degradable strain sensor was fabricated on a paper substrate by dip-coating in an aqueous suspension of carbon black (CB) and carboxymethyl cellulose (CMC). The composition of CB and CMC in the suspension was first studied for producing a uniform conducting layer on the paper. Then the strain sensor was obtained by assembling the coated paper and wires with silver paste. The sensor exhibits gauge factor of 4.3 and responsive time of approximately 240 ms, demonstrating the capability of monitoring various human motions with high stability >1000 cycles. The microgaps between CB particles and cracks on the surface of the CB layer can account for this resistive-type sensitivity. The degradation test shows that the sensor can be degraded soon under gentle rubbing in wet state, implying it is an environmentally friendly “green” electronic device. Furthermore, the cost of the sensor is quite low (<$0.001/sensor) due to the cheap raw materials used, which provides an opportunity for its future utilization in various intelligent systems.

中文翻译：

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低成本的柔性可降解纸基应变传感器

用可降解材料制造低成本和柔性电子设备是一个挑战。在这项工作中，通过在炭黑（CB）和羧甲基纤维素（CMC）的水悬浮液中浸涂，在纸质基材上制造了柔性且可降解的应变传感器。首先研究了悬浮液中CB和CMC的成分，以在纸上产生均匀的导电层。然后通过将涂布纸和电线与银浆组装在一起来获得应变传感器。该传感器的规格系数为4.3，响应时间约为240毫秒，证明了能够以大于1000个周期的高稳定性监视各种人体运动。CB颗粒之间的微间隙和CB层表面上的裂缝可以解释这种电阻型灵敏度。退化测试表明，该传感器在潮湿状态下进行轻柔摩擦后很快就会退化，这表明它是一种环保的“绿色”电子设备。此外，由于所使用的廉价原材料，传感器的成本非常低（每个传感器<0.001美元），这为将来在各种智能系统中的使用提供了机会。