Suresha K Mahadeva studied Mechanical Engineering at the University of Mysore, India and received his B.E degree in 1999. He completed his M.Tech degree from National Institute of Technology Karnataka, India after having researched on heat transfer during solidification at metal-mold interface. He completed his Ph.D thesis in 2010 from School of Engineering, INHA University, South Korea with the research focused on developement of cellulose based hybrid composites for biomimetic actuator and sensing applications. He is currently a postdoctoral research fellow and a member of Microsystems and Nanotechnology Research Group at The University of British Columbia, Vancouver. His current research includes fabrication,characterization, and testing paper based piezoelectric materials for sensing applications.
Journal: ACS Appl. Mater. Interfaces 7(16), 8345- 8362..
Abstract: Paper is a ubiquitous material that has various applications in day to day life. A sheet of paper is produced by pressing moist wood cellulose fibers together. Paper offers unique properties: paper allows passive liquid transport, it is compatible with many chemical and biochemical moieties, it exhibits piezoelectricity, and it is biodegradable. Hence, paper is an attractive low-cost functional material for sensing devices. In recent years, researchers in the field of science and engineering have witnessed an exponential growth in the number of research contributions that focus on the development of cost-effective and scalable fabrication methods and new applications of paper-based devices. In this review article, we highlight recent advances in the development of paper-based sensing devices in the areas of electronics, energy storage, strain sensing, microfluidic devices, and biosensing, including piezoelectric paper. Additionally, this review includes current limitations of paper-based sensing devices and points out issues that have limited the commercialization of some of the paper-based sensing devices.
Conference: IEEE MEMS-2015..
Abstract: We have developed robust and mechanically flexible piezoelectric paper. The fabrication process involves functionalization of barium titanate (BaTiO3) 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 (d33 = 37 – 45.7 ± 4.2 pC/N) and is comparable to that of commercially available piezoelectric polymers such as polyvinylidene fluoride with d33 = 30 pC/N. In addition, we have demonstrated the application of this paper as a tactile sensor.
Journal: ACS Appl. Mater. Interfaces 6(10), 7547- 7553..
Abstract: We have successfully developed hybrid piezoelectric paper through fiber functionalization that involves anchoring nanostructured BaTiO3 into a stable matrix with wood cellulose fibers prior to the process of making paper sheets. This is realized by alternating immersion of wood fibers in a solution of poly(diallyldimethylammonium chloride) PDDA (+), followed by poly(sodium 4-styrenesulfonate) PSS (−), and once again in PDDA (+), resulting in the creation of a positively charged surface on the wood fibers. The treated wood fibers are then immersed in a BaTiO3 suspension, resulting in the attachment of BaTiO3 nanoparticles to the wood fibers due to a strong electrostatic interaction. Zeta potential measurements, X-ray diffraction, and microscopic and spectroscopic analysis imply successful functionalization of wood fibers with BaTiO3 nanoparticles without altering the hydrogen bonding and crystal structure of the wood fibers. The paper has the largest piezoelectric coefficient, d33 = 4.8 ± 0.4 pC N–1, at the highest nanoparticle loading of 48 wt % BaTiO3. This newly developed piezoelectric hybrid paper is promising as a low-cost substrate to build sensing devices.
Conference: IEEE MEMS-2014..
Abstract: 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).
Journal: J. Phys. D: Appl. Phys. 46(28), 285305..
Abstract: Corona poling was used to create piezoelectric polyvinylidene flouride (PVDF) thin films and the effects of poling time and grid voltage on the electric and physical properties of the samples was studied. Using x-ray diffraction, infrared spectroscopy, and direct measurement of piezoelectricity, the phase transition behaviour and piezoelectric constant of stretched and poled PVDF film was investigated. Results indicate that the poling time and grid voltage have no substantial influence on the phase transition behaviour of PVDF. However, they were found to have a significant effect on the piezoelectric charge constant of PVDF.