Fabrication and testing of piezoelectric hybrid paper for MEMS applications

We have developed and demonstrated a new inexpensive and environmentally friendly functional paper based material that can be used as a piezoelectric substrate for sensing applications. The process involves embedding nanostructured barium titanate (BaTiO₃) into a stable matrix of wood fibers via fiber functionalization. This is achieved by employing a layer-by-layer approach, and results in the creation of a positively charged surface on the wood fibers. The treated wood fibers are then immersed in a BaTiO₃ suspension, leading to the electrostatic binding of the BaTiO₃ nanoparticles. We have investigated hybrid paper samples with five different BaTiO₃ concentrations (8-48 wt%), and we have found the highest piezoelectric coefficient at 48 wt% BaTiO₃. Our study suggests that functionalizing wood cellulose fibers with nanostructured BaTiO₃ is a promising approach to enhancing the functionality and value of paper for developing low-cost microelectromechanical systems (MEMS).