• Tuukkanen, Sampo
• Rajala, Satu

Abstract

SUMMARY<br/>We report the experimental results on piezoelectricity of nanocellulose films. The piezoelectric sensor elements were prepared usign a nanocellulose film as a sensing layer. The piezoelectric sensitivity values from 2-7 pC/N were obtained for the prepared sensor elements. <br/><br/>KEYWORDS: Nanocellulose, piezoelectric sensor, cellulose nanofibrils, polyvinylidenefluoride<br/><br/>INTRODUCTION<br/>Cellulose based nanomaterials, generally known as nanocellulose [1], are interesting renewable bio-based nanomaterials which have potential applications in material sciences, electronics and biomedical engineering and diagnostic. The piezoelectricity of wood initiates from the highly crystalline assemblies of cellulose chains [2]. Experimental evidence of the piezoelectricity of cellulose nanocrystals (CNC) was reported only very recently [3,4]. Cellulose nanofibrils (CNF), produced by a mechanical homogenizing process from cellulose fibers, contain both crystalline and amorphous regions (see Figure 1). CNC can be made from CNF by removal of amorphous regions using hydrolysis.<br/><br/>EXPERIMENTAL<br/>The piezoelectric sensitivity of prepared sensor elements is measured using in-house built measurement setup equipped with a mechanical shaker and charge amplifier (See Figure 2). The setup is described elsewhere in details [5].<br/><br/>RESULTS AND DISCUSSION<br/>A randomly oriented CNF film (prepared by pressure filtering from aqueous CNF dispersion) showed piezoelectric sensitivities of 2-7 pC/N [6,7]. The values align between the piezoelectric coefficients of quartz (2.3 pC/N) and polyvinylidenefluoride (PVDF, -30 pC/N). <br/><br/>CONCLUSION<br/>In this work, we have successfully demonstrated the fabrication of piezoelectric sensors using nanocellulose as a sensing material. Based on these findings, nanocellulose seems a promising material for sensors and energy harvesting applications. <br/><br/>REFERENCES<br/>[1] Moon, R. J., et al. "Cellulose nanomaterials review: structure, properties and nanocomposites." Chemical Society Reviews 40.7 (2011): 3941.<br/>[2] Fukada, E. "Piezoelectricity of wood." Journal of the Physical Society of Japan 10.2 (1955): 149.<br/>[3] Csoka, L. et al. "Piezoelectric effect of cellulose nanocrystals thin films." ACS Macro Letters 1.7 (2012): 867.<br/>[4] Frka-Petesic, B. et al. "First experimental evidence of a giant permanent electric-dipole moment in cellulose nanocrystals." Europhysics Letters 107.2 (2014): 28006.<br/>[5] Rajala, S. et al. “Structural and Electrical Characterization of Solution-Processed Electrodes for Piezoelectric Polymer Film Sensors.” IEEE Sensors Journal (Accepted for publication 2015).<br/>[6] Rajala, S. et al. "Piezoelectric sensitivity measurements of cellulose nanofibrils sensors." Proc. XXI IMEKO World Congr., Prague, Czech Republic (2015).<br/>[7] Tuukkanen, S. et al. "A survey of printable piezoelectric sensors." In: Proceedings of IEEE Sensors 2015 Conference, (2015): 1426.<br/> <br/>

Topics

• nanocomposite
• impedance spectroscopy
• dispersion
• polymer
• amorphous
• thin film
• wood
• cellulose