Crystallinity-controlled deformation behavior of Eucommia Ulmoides rubber for multifunctional flexible sensors

Flexible multi-functional sensors are highly desirable for health monitoring and human-computer interaction due to their adaptability and mechanical flexibility. However, materials with tunable properties for the sensitive response and flexibility of the sensors are in highly shortage. To relive this issue, we propose a novel strategy that adjusts crystallinity () to enhance the lateral deformation (LD) of Eucommia ulmoides rubber (EUR) under compression, thereby improving the sensor performance. We successfully prepared a series of EUR elastomer (EURE) composites with controllableby destroying the internal crystalline structure of EUR via epoxidation, followed by blending and vulcanization with varying amounts of EUR. The results show that the LD capability of EURE composites under compression significantly increases asdecreases. One-At-a-Time partial sensitivity analysis (OAT) reveals that Young's modulus (E) is the dominant factor governing the change in LD. Subsequently, graphite was introduced into the EURE composite to fabricate sensor. The sensor exhibits a pressure sensitivity of 2.28% kPa-1 in the range of 0-12 kPa, a rapid response time of 0.63 s, robust cycling stability, and a temperature coefficient of resistance (TCR) of 0.57% ℃-1 over 15-55 ℃. Successfully monitoring the temperature fluctuations and human motions in excellent electrical responses confirms its promising potential for fabricating wearable sensors.