Structural and dimensional engineering of three-dimensional carbon nanotube/polydimethylsiloxane composite for stretchable sensor

A highly sensitive strain sensor is essential for the wearable electronic in constantly emerging applications such as human motion monitoring, personalized healthcare, human-machine interaction, soft robot and smart skin. However, most of the physical sensors currently reported are facing with challenges of non-adjustable sensing performance, unsatisfactory linearity, complicated preparation processes, and small working ranges, which greatly restricts their practical applicability. In this work, we proposal a facile technology base on the structural and dimensional engineering of carbon nanotube (CNT) conducting networks, to fabricate the flexible and stretchable strain sensor with tunable sensitivity and superior linearity in a wide sensing range. The three-dimensional CNT frameworks with adjustable density were constructed by the chemical vapor deposition method, which were used as the filler network to prepare the flexible CNT/polydimethylsiloxane (CNT/PDMS) composites. The resultant strain sensors base on the CNT/PDMS composites can realize the tunable sensitivities (gauge factor ranges from 0.7 to 233 at 100 % strain) by simply changing and regulating the structural density and macro-size of sensing strips. Meanwhile, the obtained sensors possess excellent linearity (R2 > 90 %) and repeatability on the 10 000 cycles. The technology developed in this work will offer a wide range of practical applications in wearable electronics field.