Piezoelectric paper for physical sensing applications

We have developed robust and mechanically flexible piezoelectric paper. The fabrication process involves functionalization of barium titanate (BaTiO
₃
) nanostructures onto wood fibers, followed by activation in a suspension of the commercially available paper-strength-enhancing additive, carboxymethyl cellulose (CMC), which improves fiber-fiber bonding. This leads to piezoelectric paper with both high tensile strength and flexibility. We have investigated the effect of CMC concentration (2-6 wt%) on the tensile properties of the paper and found the highest tensile strength at 6wt% CMC. This piezoelectric paper has the largest piezoelectric coefficient reported for paper to date (d
₃₃
= 37 - 45.7 ± 4.2 pC/N) and is comparable to that of commercially available piezoelectric polymers such as polyvinylidene fluoride with d
₃₃
= 30 pC/N. In addition, we have demonstrated the application of this paper as a tactile sensor.