Cellulose Nanofibril Film as a Piezoelectric Sensor Material

Abstract

Self-standing films (45-μm thick) of native cellulose nanofibrils (CNF) 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  of 0.011 and 0.071, respectively. The films were used as functional sensing layers in piezoelectric sensors with corresponding sensitivities of 4.7 to 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, actuator or energy generators with potential applications in the fields of electronics, sensors and biomedical diagnostics.

Biodegradable, electro-active chitin nanofiber films for flexible piezoelectric transducers

“…[18][19] In recent years, piezoelectric biopolymer such as polysaccharides (e.g., chitin [20][21] and cellulose [22][23][24] and proteins (e.g., silk 25 ) have been focused to overcome these drawbacks due to non-toxicity and eco-friendly characteristics in Figure 1.2. 9,12,[25][26] In particular, chitin is the second most abundant natural polysaccharide that are being produced at 100 billion tons/year 25 and has the piezoelectric properties (due to intrinsic molecular polarization arising from the noncentrosymmetric crystal structure of α-and β-chitin polymorphs). However, the piezoelectricity of chitin material have rarely been studied since the first discovery of piezoelectricity in 1975 by Eiichi Fukada.…”

“…This d33 value of β-chitin is similar with that of cellulose materials. 26 In addition, the theoretical polarization values of α-and β-chitin was calculated by density functional theory (DFT) simulation by using The Vienna Ab-initio Simulation Package (VASP). [32][33] While the theoretical spontaneous polarization value of α-chitin is 0 C/m 2 in both case of O6A and O6B conformation, the net polarization value of β-chitin is 1.87 C/m 2 along the [00 ̅ ] direction under the boundary conditions in Table 1.…”

Nanostructured polymer-based piezoelectric and triboelectric materials and devices for energy harvesting applications

“…Copyright 2013 American Chemical Society. [36,37]. In the case of poly-L-lactic acid (PLLA), there are four known crystal phases (α′, α, β and γ) based around a helical conformation of the polymer chain.…”

Low-temperature atomic layer deposition of SiO 2 /Al 2 O 3 multilayer structures constructed on self-standing films of cellulose nanofibrils

“…These include, for example, piezoelectric properties, low thermal conductivity, high thermal stability, and low density coupled with relatively high strength as well as the ability to form flexible films that can act as a gas barrier material. [4][5][6][7] Hybrid structures combining organic with inorganic materials are commonplace and many of the applications, like solar cells, are based on thin film technology. [8] The use of biopolymers, however, has remained a largely unexplored area with thin film hybrids, particularly concerning plant-based polysaccharides like cellulose.…”