| dc.description.abstract | Cellulose nanomaterials have recently continued to attract higher attention in the current research output, due to their extremely excellent mechanical, optical as well as electrical properties. Their sustainability coupled with good structural and morphological properties have made them become a great resource in the construction of both active and passive components in the electronics sector. Interestingly, water hyacinth, a serious environmental threat in Lake Victoria and other water bodies globally, is a rich source of this novel material. This research study has been dedicated to find out the correlation between the degree of alignment and the piezoelectric effect of cellulose nanocrystals fabricated from water hyacinth. The CNCs were synthesized by a rigorous acid hydrolysis using varied acids, concentration, temperature and time and the effects of these parameters on the opto-structural properties of the resultant films investigated using UV Visspectrophotometer, fluorescence spectrophotometer and XRD technique.Further, the Urbach energies have been calculated and found to increase while the optical band gap energies found to decrease with increase in hydrolysis temperature. From a plot of Eg verses Eu, the optical band gap energy of the CNCs when there was no disorder in their microstructure was found to be ~5.43 eV. Further, it has been shown that the Urbach energy is absent when hydrolysis process is done at 14.23oC. Additionally, the piezoelectric effect of the electric field assisted convective
shear assembled CNCs has been systematically studied and the effect of the applied voltage and the frequency mapped. The sensitivity of fabricated sensors was measured using the fabricated measurement setup. From the study, a high degree of CNC orientation in the films has been found to be a key characteristic for the piezoelectric response. The amount of applied voltage and the frequency have been found to increase the degree of the orientation/alignment of the CNCs within the films hence leading to enhanced piezoelectric response. This is because the orientation of crystalline CNC regions inside the films led to a remarkable increase of piezoelectric effect as a result of the large piezoelectric coefficient of the CNCs. From the study, it was clear that functional piezoelectric sensors can be fabricated from CNF films and thus, the results obtained suggests that CNC films are suitable sensor materials for applications in different fields including electronics, biomedical diagnostics and material sciences. | en_US |
