Bio-ferroelectric composites represent an inexpensive and environmentally friendly electronic alternative for electrical applications such as capacitors, transistors, and actuators. The present research relates to the development of a biocomposite made of a chitosan–cellulose polymeric layer and bearing ferroelectric nanoparticles. The variables considered included the volume percentage of cellulose (15 v% and 25 v%) in the matrix and the amount of ferroelectric nanoparticles (0 wt.%, 10 wt.%, and 20 wt.%). Upon electrical characterization, the results indicated that the addition of the nanoparticles raised the capacitance and resistivity of the composite while the addition of cellulose lessened both electrical properties. The measured capacitance of the composites diminished as the applied voltage increased when contrasted with commercial capacitors where under similar testing conditions, as expected, the said capacity remained constant. Additionally, higher current flows were obtained for those capacitors than for a capacitor made with the nanocomposite. In general, it is proposed that capacitors made of this biopolymer reinforced with ferroelectric particles be suitable for radio frequency and microwave applications in which high electrical tunability and low dielectric loss are required.
Materials that exhibit very high absorption and low reflectance at optical frequencies are important in a variety of light harvesting applications. We explore nano-scale topography of bulk metallic glasses to realize metallic surfaces with controllable reflectance. Diffuse reflectance as low as 1.6% in the visible range is achieved with nano-patterned Pt-based model bulk metallic glass without further optimization. Effect of pattern dimensions (size, spacing, and aspect-ratio) on the reflectance of bulk metallic glasses is investigated using a combination of simulation and experiments. V C 2015 AIP Publishing LLC. [http://dx.
In recent years, scientists advanced the study of bio-ferroelectric composites to develop new environmentally friendly and inexpensive electronic elements such as capacitors, actuators, and transistors. Accordingly, the present research relates to composites made of chitosan-cellulose polymeric matrix and strontium titanate (STO) nanoparticles. The variables considered include different percentages of cellulose (15 and 25 v%) and strontium titanate nanoparticles (10 and 20 wt%). The electrical characterization of the composites included measuring their dielectric constant, current density, and conductivity. The results suggest that the addition of STO nanoparticles raised the dielectric constant while lowering the current density and the conductivity of the nanocomposites. Moreover, although the cellulose addition increased the current density and the conductivity of the composites, it lowered their dielectric constant. Also, the resulting biocomposite capacitors could withstand up to 60 V without any detectable dielectric breakdown. The other two properties measured were the ultimate tensile strength (UTS) and the degradation temperature (Tdeg). Higher percentages of cellulose decreased the UTS and the Tdeg of the chitosan-cellulose composites while the addition of cellulose slightly raised these properties of the composites made of chitosan-cellulose and STO nanoparticles. The results proved that these types of biocomposites are apt as capacitors with adequate strength to withstand aggressive environments. This work was fully conducted in the facilities of the Nanotechnology Center hosted by the University of Puerto Rico -Mayagüez,
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