A novel biopolymer gel-electrolyte system was prepared using κ- carrageenan as polymer host incor... more A novel biopolymer gel-electrolyte system was prepared using κ- carrageenan as polymer host incorporated with I - /I3 - redox couple dissolved in an environmentally benign solvent dimethylsulfoxide (DMSO). When the κ-carrageenan concentration is at 2% w/v, it forms a gel at room temperature. The gel-polymer electrolyte system was used in dye-sensitized solar cell (DSSC) applications with the configuration TiO2/dye/κ-carrageenan gel electrolyte/Pt sandwiched in between two FTO conducting glass substrates. The assembled DSSC was characterized using EIS technique to describe the charge-transfer processes occurring in its interfaces and IV- measurements under AM 1.5 illumination to determine the overall solar cell efficiency. Comparison with DSSC without κ-carrageenan revealed better efficiency due to less charge recombination process occurring in the TiO2/dye/electrolyte interface.
Highlights • First report on structural change in κ-carrageenan under ultrasonic condition.• Soni... more Highlights • First report on structural change in κ-carrageenan under ultrasonic condition.• Sonication decreased the average molecular weight of κ-carrageenan.• Sonication afforded minor modification in the structure of the κ-carrageenan repeating units.
Solid electrolyte system compared to a liquid electrolyte is desirable for some electrochemical a... more Solid electrolyte system compared to a liquid electrolyte is desirable for some electrochemical applications. Natural polymers like polysaccharides were explored as polymer matrix in the development of solid electrolyte system. Among the polysaccharides screened, κcarrageenan showed promising results. Cyclic voltammetry of the I3 /I redox couple in κcarrageenan gel showed improved performance compared to aqueous medium. Composite films of κ-carrageenan with KI and I2 as triiodide sources and polymer electrolytes based on κcarrageenan and ionic liquid, 1,3-dimethyl imidazolium iodide (DMII) with I2 were prepared and characterized. The composite characterizations indicate that lower conductivity using Van der Pauw technique was observed with KI/I2 system owing to its porous surface. The κcarrageenan/DMII/I2 system on the other hand showed a smooth surface and significantly higher conductivity making it a promising solid electrolyte system.
A halogen-free ionic liquid (IL) designed with long alkyl chain anion is reported. 1-methylimidaz... more A halogen-free ionic liquid (IL) designed with long alkyl chain anion is reported. 1-methylimidazolium stearate (MIM stearate) synthesized through Bronsted acid-base reaction has shown improved lipophilic character and is able to penetrate bacterial cell walls. Antimicrobial activities against Gram-negative bacteria, Escherichia coli, and Pseudomonas aeruginosa were observed. Anti-biofilm assays showed effectivity against the biofilm of Pseudomonas aeruginosa. At 50 µg/mL the %biofilm inhibition of MIM stearate towards P. aeruginosa biofilm formation is comparable to the Bromofuran positive control. Brine shrimp lethality assay showed weak toxicity indicating the IL to be safe and benign. The synthesized MIM stearate showed good promise as an antimicrobial and anti-biofilm agent.
IOP Conference Series: Materials Science and Engineering, 2015
Poly(3,4-ethylenedioxythiophene) (PEDOT)-κ-carregeenan polymer electrolyte blend was prepared and... more Poly(3,4-ethylenedioxythiophene) (PEDOT)-κ-carregeenan polymer electrolyte blend was prepared and incorporated as the electrolyte system in dye-sensitized solar cells (DSSC). Polymer blends prepared with different κ-carrageenan concentrations and molecular weights were investigated. It was found that the conductivity of the polymer blend increases with higher κ-carrageenan concentration, and lowers with degraded κ-carregeenan. The polymer blend was incorporated in a DSSC and yielded a solar cell with efficiency (η) of 0.421%.
For the first time, in this paper, synchrotron-based Fourier transform infrared spectroscopy char... more For the first time, in this paper, synchrotron-based Fourier transform infrared spectroscopy characterized the changes in the short-order range of potato starch after ultrasonication. Ultrasonic treatment caused cracks and fissures on potato starch granules. Simultaneously, size exclusion chromatography revealed that the ultrasonic treatment having 53 kHz did not induce scissoring of the glycosidic bond of starch. Differential scanning calorimetry showed decreased thermal parameters (To, Tp and ΔH) of potato starch, indicating a disorder in the starch molecule. Furthermore, synchrotron-based FTIR gives insights on the loosening of short-range order of potato starch as reported by the disruption of the crystalline region of potato starch.
A novel biopolymer gel-electrolyte system was prepared using κ- carrageenan as polymer host incor... more A novel biopolymer gel-electrolyte system was prepared using κ- carrageenan as polymer host incorporated with I - /I3 - redox couple dissolved in an environmentally benign solvent dimethylsulfoxide (DMSO). When the κ-carrageenan concentration is at 2% w/v, it forms a gel at room temperature. The gel-polymer electrolyte system was used in dye-sensitized solar cell (DSSC) applications with the configuration TiO2/dye/κ-carrageenan gel electrolyte/Pt sandwiched in between two FTO conducting glass substrates. The assembled DSSC was characterized using EIS technique to describe the charge-transfer processes occurring in its interfaces and IV- measurements under AM 1.5 illumination to determine the overall solar cell efficiency. Comparison with DSSC without κ-carrageenan revealed better efficiency due to less charge recombination process occurring in the TiO2/dye/electrolyte interface.
Highlights • First report on structural change in κ-carrageenan under ultrasonic condition.• Soni... more Highlights • First report on structural change in κ-carrageenan under ultrasonic condition.• Sonication decreased the average molecular weight of κ-carrageenan.• Sonication afforded minor modification in the structure of the κ-carrageenan repeating units.
Solid electrolyte system compared to a liquid electrolyte is desirable for some electrochemical a... more Solid electrolyte system compared to a liquid electrolyte is desirable for some electrochemical applications. Natural polymers like polysaccharides were explored as polymer matrix in the development of solid electrolyte system. Among the polysaccharides screened, κcarrageenan showed promising results. Cyclic voltammetry of the I3 /I redox couple in κcarrageenan gel showed improved performance compared to aqueous medium. Composite films of κ-carrageenan with KI and I2 as triiodide sources and polymer electrolytes based on κcarrageenan and ionic liquid, 1,3-dimethyl imidazolium iodide (DMII) with I2 were prepared and characterized. The composite characterizations indicate that lower conductivity using Van der Pauw technique was observed with KI/I2 system owing to its porous surface. The κcarrageenan/DMII/I2 system on the other hand showed a smooth surface and significantly higher conductivity making it a promising solid electrolyte system.
A halogen-free ionic liquid (IL) designed with long alkyl chain anion is reported. 1-methylimidaz... more A halogen-free ionic liquid (IL) designed with long alkyl chain anion is reported. 1-methylimidazolium stearate (MIM stearate) synthesized through Bronsted acid-base reaction has shown improved lipophilic character and is able to penetrate bacterial cell walls. Antimicrobial activities against Gram-negative bacteria, Escherichia coli, and Pseudomonas aeruginosa were observed. Anti-biofilm assays showed effectivity against the biofilm of Pseudomonas aeruginosa. At 50 µg/mL the %biofilm inhibition of MIM stearate towards P. aeruginosa biofilm formation is comparable to the Bromofuran positive control. Brine shrimp lethality assay showed weak toxicity indicating the IL to be safe and benign. The synthesized MIM stearate showed good promise as an antimicrobial and anti-biofilm agent.
IOP Conference Series: Materials Science and Engineering, 2015
Poly(3,4-ethylenedioxythiophene) (PEDOT)-κ-carregeenan polymer electrolyte blend was prepared and... more Poly(3,4-ethylenedioxythiophene) (PEDOT)-κ-carregeenan polymer electrolyte blend was prepared and incorporated as the electrolyte system in dye-sensitized solar cells (DSSC). Polymer blends prepared with different κ-carrageenan concentrations and molecular weights were investigated. It was found that the conductivity of the polymer blend increases with higher κ-carrageenan concentration, and lowers with degraded κ-carregeenan. The polymer blend was incorporated in a DSSC and yielded a solar cell with efficiency (η) of 0.421%.
For the first time, in this paper, synchrotron-based Fourier transform infrared spectroscopy char... more For the first time, in this paper, synchrotron-based Fourier transform infrared spectroscopy characterized the changes in the short-order range of potato starch after ultrasonication. Ultrasonic treatment caused cracks and fissures on potato starch granules. Simultaneously, size exclusion chromatography revealed that the ultrasonic treatment having 53 kHz did not induce scissoring of the glycosidic bond of starch. Differential scanning calorimetry showed decreased thermal parameters (To, Tp and ΔH) of potato starch, indicating a disorder in the starch molecule. Furthermore, synchrotron-based FTIR gives insights on the loosening of short-range order of potato starch as reported by the disruption of the crystalline region of potato starch.
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Papers by Drexel Camacho