scholarly journals Thermal Annealing Effect on Structural, Morphological, and Sensor Performance of PANI-Ag-Fe Based ElectrochemicalE. coliSensor for Environmental Monitoring

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Norshafadzila Mohammad Naim ◽  
H. Abdullah ◽  
Akrajas Ali Umar ◽  
Aidil Abdul Hamid ◽  
Sahbudin Shaari

PANI-Ag-Fe nanocomposite thin films based electrochemicalE. colisensor was developed with thermal annealing. PANI-Ag-Fe nanocomposite thin films were prepared by oxidative polymerization of aniline and the reduction process of Ag-Fe bimetallic compound with the presence of nitric acid and PVA. The films were deposited on glass substrate using spin-coating technique before they were annealed at 300°C. The films were characterized using XRD, UV-Vis spectroscopy, and FESEM to study the structural and morphological properties. The electrochemical sensor performance was conducted usingI-Vmeasurement electrochemical impedance spectroscopy (EIS). The sensitivity upon the presence ofE. coliwas measured in clean water andE. colisolution. From XRD analysis, the crystallite sizes were found to become larger for the samples after annealing. UV-Vis absorption bands for samples before and after annealing show maximum absorbance peaks at around 422 nm–424 nm and 426 nm–464 nm, respectively. FESEM images show the diameter size for nanospherical Ag-Fe alloy particles increases after annealing. The sensor performance of PANI-Ag-Fe nanocomposite thin films uponE. colicells in liquid medium indicates the sensitivity increases after annealing.

2015 ◽  
Vol 1119 ◽  
pp. 101-105 ◽  
Author(s):  
Huda Abdullah ◽  
Norshafadzila Mohammad Naim ◽  
Noor Azwen Noor Azmy ◽  
Akrajas Ali Umar ◽  
Aidil Abdul Hamid ◽  
...  

The nanocomposite of polyaniline (PANI) and bimetallic nanoparticles of silver and iron were prepared by the oxidative polymerization of aniline and the reduction process of bimetallic compound with the presence of nitric acid and PVA. The nanocomposite thin films in various compositions were deposited using spin-coating technique. The films were characterized by UV-visible spectroscopy to study the optical and structural properties. The microphotograph from TEM image shows the nanospherical of Ag-Fe alloy particles in 5 – 25 nm diameter size. The sensitivity performance was tested using I-V measurement to obtain the changes of resistivity before and after the incubation with E. coli bacteria in water. UV-visible absorption bands show the single absorbance peak at 422 – 424 nm in each band indicating the Ag-Fe alloy nanoparticles form. I-V characteristic shows the sample which contains Fe-rich Ag-Fe alloy performed high sensitivity on E. coli.


2016 ◽  
Vol 846 ◽  
pp. 641-649 ◽  
Author(s):  
Norshafadzila Mohammad Naim ◽  
Huda Abdullah ◽  
Noor Azwen Noor Azmy ◽  
Akrajas Ali Umar ◽  
Aidil Abdul Hamid ◽  
...  

Conducting polymers are excellent host materials for nanoparticles of metals and semiconductors. PANI-Ag-Co nanocomposite was prepared by chemical oxidative polymerization of aniline monomer in the presence of nitric acid. PANI-Ag-Co thin films were deposited on the glass substrate using spin-coating technique. The films were characterized by UV-Vis spectroscopy, XRD, AFM and TEM to analyze the internal structure and surface morphology. The performance of the sensor was conducted using I–V measurement to obtain the changes in the current before and after the incubation with E. coli bacteria in water. In UV-visible absorbance bands, a single peak appears at 421.6 nm in each band indicating the Ag-Co alloy nanoparticles were formed. The peaks in the XRD patterns show the crystals are oriented along (111) planes for Ag while (200) plane for Co. AFM images indicate the surface roughness of the PANI-Ag-Co films decreases when the concentration of Co increased. TEM image shows spherical shaped of Ag-Co alloy particles with diameter in the range of 6 – 10 nm. I–V measurements show that the current change of the films increased when incubated in E. coli. The sensitivity on E. coli increases as we increase the Co concentration. PANI-Ag-Co nanocomposite thin films can be explored further for microbial sensor application in future study.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Huda Abdullah ◽  
Norshafadzila Mohammad Naim ◽  
Noor Azwen Noor Azmy ◽  
Aidil Abdul Hamid

PANI-Ag-Cu nanocomposite thin films were prepared by sol-gel method and deposited on the glass substrate using spin coating technique. Polyaniline was synthesized by chemical oxidative polymerization of aniline monomer in the presence of nitric acid. The films were characterized using XRD, FTIR, and UV-Visible spectroscopy. The performance of the sensor was conducted using electrochemical impedance spectroscopy to obtain the change in impedance of the sensor film before and after incubation withE. colibacteria in water. The peaks in XRD pattern confirm the presence of Ag and Cu nanoparticles in face-centered cubic structure. FTIR analysis shows the stretching of N–H in the polyaniline structure. The absorption band from UV-Visible spectroscopy shows high peaks between 400 nm and 500 nm which indicate the presence of Ag and Cu nanoparticles, respectively. Impedance analysis indicates that the change in impedance of the films decreases with the presence ofE. coli. The sensitivity onE. coliincreases for the sample with high concentration of Cu.


Author(s):  
Huda Abdullah ◽  
Muhamad Aiman Kamarudin ◽  
Norshafadzila Mohammad Naim ◽  
Aidil Abdul Hamid ◽  
Mohd Hafiz Dzarfan Othman

2014 ◽  
Vol 911 ◽  
pp. 131-135 ◽  
Author(s):  
H. Abdullah ◽  
Noor Azwen Noor Azmy ◽  
Norshafadzila Mohammad Naim ◽  
Aisyah Bolhan ◽  
Aidil Abdul Hamid ◽  
...  

Polymers are excellent host materials for nanoparticles of metals and semiconductors. PVAAgCu nanocomposite was synthesized from chemical reduction, whereas PANIAgCu nanocomposite was synthesized by chemical oxidative polymerization. PVAAgCu and PANIAgCu thin films were deposited on the glass substrate by spin coating technique. The films were characterized by using XRD and AFM. The sensitivity of the samples was analyzed by IV measurement. The peaks in XRD patterns confirm the presence of Ag-Cu nanoparticles in face centered cubic structure. AFM images show the roughness of PVAAgCu and PANIAgCu increased as Ag concentration decreased and Cu concentration increased. I-V measurements indicate that the change in the current of the films increases with the presence of E. coli. The sensitivity on E. coli increases for PVAAgCu and PANIAgCu thin films with high concentration of Cu.


2019 ◽  
Vol 786 ◽  
pp. 750-757 ◽  
Author(s):  
Jaspal Singh ◽  
Kavita Sahu ◽  
Ranveer Singh ◽  
T. Som ◽  
R.K. Kotnala ◽  
...  

2019 ◽  
Vol 26 (05) ◽  
pp. 1850197 ◽  
Author(s):  
SELMA M. H. AL-JAWAD ◽  
SABAH H. SABEEH ◽  
ALI A. TAHA ◽  
HUSSEIN A. JASSIM

Pure and Fe-doped zinc oxide (ZnO) sol–gel thin films were deposited by spin-coating process. Pure ZnO and Fe–ZnO films, containing Fe of 2–8[Formula: see text]wt.%, were annealed at 500∘C for 2[Formula: see text]h. All prepared thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV–visible (UV–vis) spectroscopy. XRD studies show the polycrystalline nature with hexagonal wurtzite structure of pure ZnO and Fe–ZnO thin films. The crystallite size of the prepared samples reduced with increasing Fe doping concentrations. AFM and SEM results indicated that the average grain size decreased as Fe doping concentration increased. The transmittance spectra were then recorded at wavelengths ranging from 300[Formula: see text]nm to 1000[Formula: see text]nm. The films produced yielded high transmission at visible regions. The optical bandgap energy of spin-coated films also decreased as Fe doping concentration increased. In particular, their optical bandgap energies were 3.75, 3.6, 3.5, 3.45 and 3.3 eV at 0-, 2-, 4-, 6- and 8-wt.% Fe concentrations, respectively. Antibacterial activities of pure ZnO and Fe–ZnO against E. coli and S. aureus were evaluated by international recognized test (JIS Z 2801). The results showed that pure and Fe-doped ZnO thin films have antibacterial inhibition zone against E. coli and S. aureus. Gram-positive bacteria seemed be more resistant to pure and Fe-doped ZnO thin films than gram-negative bacteria. The test shows an incremental increase in antibacterial activity of the thin films when dopant ratio increased under UV light.


Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 468
Author(s):  
Marcela Socol ◽  
Nicoleta Preda ◽  
Andreea Costas ◽  
Bogdana Borca ◽  
Gianina Popescu-Pelin ◽  
...  

Matrix-assisted pulsed laser evaporation (MAPLE) was used to deposit hybrid nanocomposite thin films based on cobalt phthalocyanine (CoPc), C60 fullerene and ZnO nanoparticles. The inorganic nanoparticles, with a size of about 20 nm, having the structural and optical properties characteristic of ZnO, were chemically synthesized by a simple precipitation method. Furthermore, ZnO nanoparticles were dispersed in a dimethyl sulfoxide solution in which CoPc and C60 had been dissolved, ready for the freezing MAPLE target. The effect of the concentration of ZnO nanoparticles on the structural, morphological, optical and electrical properties of the CoPc:C60:ZnO hybrid nanocomposite layers deposited by MAPLE was evaluated. The infrared spectra of the hybrid nanocomposite films confirm that the CoPc and C60 preserve their chemical structure during the laser deposition process. The CoPc optical signature is recognized in the ultraviolet–visible (UV–Vis) spectra of the obtained layers, these being dominated by the absorption bands associated to this organic compound while the ZnO optical fingerprint is identified in the photoluminescence spectra of the prepared layers, these disclosing the emission bands linked to this inorganic semiconductor. The hybrid nanocomposite layers exhibit globular morphology, which is typical for the thin films deposited by MAPLE. Current-voltage (J-V) characteristics of the structures developed on CoPc:C60:ZnO layers reveal that the addition of an appropriate amount of ZnO nanoparticles in the CoPc:C60 mixture leads to a more efficient charge transfer between the organic and inorganic components. Due to their photovoltaic effect, structures featuring such hybrid nanocomposite thin films deposited by MAPLE can have potential applications in the field of photovoltaic devices.


2005 ◽  
Vol 60 (11) ◽  
pp. 1158-1167 ◽  
Author(s):  
Yuh-Fan Su ◽  
Tse-Chuan Chou

Correlations between the photocatalytic and photoelectrocatalytic decolorization of methyl orange, using TiO2 thin films sputtered under various conditions, were made. Three types of systems, namely: two photocatalytic systems, one with and one without a Pt counter electrode, and a third with a Pt counter electrode having an applied potential, were used to evaluate photocatalytic activity.The crystal structure, morphology, bandgap energy, flatband potential, and the resistances of the TiO2 films were characterized by X-ray diffraction, scanning electron microscopy, UV/vis spectroscopy, a photocurrent method, and electrochemical impedance spectroscopy, respectively. The results showed that the decolorization of methyl orange only occurred on the anode of the TiO2/Ti electrode and that the decolorization rate increased 67% when the photocatalyst was coupled to a Pt electrode (0 V applied potential), and 275% when connected with the Pt cathode and 1 V vs. Ag/AgCl applied potential. The benefits of high crystallinity, a high quantity of the anatase, and a more negative flatband potential were found in the photocatalytic reaction, whereas the resistance of the film was the main factor affecting the photoelectrocatalytic activity.


2016 ◽  
Vol 3 (2) ◽  
pp. 538-544 ◽  
Author(s):  
Huda Abdullah ◽  
Norshafadzila Mohammad Naim ◽  
Aidil Abdul Hamid ◽  
Akrajas Ali Umar

Sign in / Sign up

Export Citation Format

Share Document