3D printed graphene/polydimethylsiloxane composite for stretchable strain sensor with tunable sensitivity.

Materials with tunable and high strain sensitivities have a great potential to be used in next generation flexible electronic devices. Conventional methods, which focus on tailoring the material composition to obtain controllable sensitivities, face the issues of complicated fabrication process and instability, restricting their use in real applications. In this work, we propose the idea of tuning the sensitivities through precisely controlled micro-structures. Based on 3D printing technique, we successfully fabricate graphene/polydimethylsiloxane composites with long range ordered porous structures. The resultant composites present tunable and high gauge factors, along with excellent durability. The tunable sensitivity comes from different strain distributions on the composites under stretching, arising from the different micro-structures constructed. Taking full advantage of the composites in terms of sensitivity and durability, we demonstrate the application of the 3D printed porous sensors as wearable human motion detectors.