Usage of conductive materials for manufacturing electronic circuits using 3D printing methods plays a prominent role in sensing applications and has achieved significant growth in recent years. This growth has led to the development of stretchable, flexible electronics and wearable electronics that are useful as sensing applications in the fields of real-time health monitoring systems. In this paper, a multiwalled carbon nanotube (MWCNT)-based electronic circuit was developed using the 3D printing technique called direct ink writing (DIW). Polyvinyl alcohol (PVA) was used as the binder material to make the MWCNT ink for printing. Different concentrations of MWCNT ink were prepared using 5, 10, and 15 wt. % PVA solutions. The viscosity of MWCNT inks was measured using a rheometer (cone and plate type). The ink exhibited shear thinning behavior, which is suitable for DIW. Finally, the printing of a designed electronic circuit was carried out using a pneumatic extrusion–based 3D printer. The strain sensor circuit—measuring 20 mm long, 9.2 mm wide, and 0.8 mm thick—is manufactured by the 3D printer. Electrical resistivity of strain sensor circuit is evaluated by adopting a two-probe method; the observed resistivity value was 1.7 × 10−2 Ωm for MWCNT ink made with 10 wt. % PVA solution and 1.97 × 10−2 Ωm for MWCNT ink made with 15 wt. % PVA solution.
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