Cellulose Nanofibril Film as a Piezoelectric Sensor Material

• DOI: 10.1021/acsami.6b03597
• Publication Date: 2016-05-27T18:55:27Z
• Authors: Satu Rajala; Tuomo Siponkoski; Essi Sarlin; Marja Mettänen; Maija Vuoriluoto; Arno Pammo; Jari Juuti; Orlando J. Rojas; Sami Franssila; Sampo Tuukkanen
• Keywords: piezoelectric sensor materials; Polymers; Surface Properties; 213 Electronic, automation and communications engineering, electronics; sensitivity measurement; cellulose nanofibrils; Nanofibers; 600; 216; 02 engineering and technology; 540; image-based analysis; relative permittivity; Chemistry Techniques, Analytical; 213; 216 Materials engineering; nanocellulose films; ta216; Cellulose; 0210 nano-technology; Electromagnetic Phenomena

Self-standing films (45 μm thick) of native cellulose nanofibrils (CNFs) were synthesized and characterized for their piezoelectric response. The surface and the microstructure of the films were evaluated with image-based analysis and scanning electron microscopy (SEM). The measured dielectric properties of the films at 1 kHz and 9.97 GHz indicated a relative permittivity of 3.47 and 3.38 and loss tangent tan δ of 0.011 and 0.071, respectively. The films were used as functional sensing layers in piezoelectric sensors with corresponding sensitivities of 4.7-6.4 pC/N in ambient conditions. This piezoelectric response is expected to increase remarkably upon film polarization resulting from the alignment of the cellulose crystalline regions in the film. The CNF sensor characteristics were compared with those of polyvinylidene fluoride (PVDF) as reference piezoelectric polymer. Overall, the results suggest that CNF is a suitable precursor material for disposable piezoelectric sensors, actuators, or energy generators with potential applications in the fields of electronics, sensors, and biomedical diagnostics.