Highly Stretchable, Directionally Oriented Carbon Nanotube/PDMS Conductive Films with Enhanced Sensitivity as Wearable Strain Sensors

• DOI: 10.1021/acsami.9b13684
• Publication Date: 2019-09-25T11:55:20Z
• Authors: Mehmet O. Tas; Mark A. Baker; Mateus G. Masteghin; Jedidiah Bentz; Keir Boxshall; Vlad Stolojan
• Keywords: Polydimethylsiloxane; Gauge factor

Recent interest in the fields of human motion monitoring, electronic skin, and human-machine interface technology demands strain sensors with high stretchability/compressibility (ε > 50%), sensitivity (or gauge factor (GF 100)), long-lasting electromechanical compliance. However, current metal- semiconductor-based have very low < 5%) stretchability or 2), typically sacrificing for sensitivity. Composite elastomer are a solution where challenge is to improve GF 100. We propose simple, low-cost fabrication mechanically compliant, physically robust metallic carbon nanotube (CNT)-polydimethylsiloxane (PDMS) sensors. The process allows alignment CNTs within PDMS elastomer, permitting directional sensing. Aligning horizontally (HA-CNTs) on substrate before embedding reduces number CNT junctions introduces scale-like features film perpendicular tensile direction, resulting improved compared vertically-aligned CNT-(VA-CNT)-PDMS under tension. modulate electron conduction pathway, affecting electrical Resulting values 594 at 15% 65 50% strains HA-CNT-PDMS 326 25% 52 VA-CNT-PDMS Under compression, show more small-scale deformation than due orientation continuous morphology film, demonstrating that sensing ability can be by aligning certain directions. Furthermore, mechanical robustness durability tested over 6000 cycles up compressive strains, good frequency responses negligible hysteresis. Finally, both types shown detect motions, successfully distinguishing various motions reaction recovery times as 130 ms 0.5 s, respectively.