Cellulose diacetate (CDA) and triacetate (CTA) were derived from Egyptian cotton to fabricate reverse osmosis (RO) membranes. The Pphase inversion method was utilized for the production of CDA-based membranes. Comprehensive characterization of these membranes involved structural, morphologial, and hydrophilic property analyses through techniques such as nuclear magnetic resonance (NMR), infrared spectroscopy, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurements. NMR spectra indicated a degree of substitution of 2.9 for CTA and 2 for CDA. The resulting RO membrane demonstrated a water flux of 6.1 L/m2 center dot h and a salt rejection of 90.3%. Annealing led to an enhanced top layer with reduced defects and macrovoids in the support layer. Moreover, grafting the RO membranes with 15 wt% of 2-acrylamidopropane-2-methyl sulphonic acid improved salt rejection to 96.2% and water flux to 8.7 L/m2.h. These findings underscore the significant performance enhancements achieved through both annealing and grafting processes in RO membranes. The cellulose triacetate prepared has a degree of substitution of 2.9. The cellulose diacetate prepared has a degree of substitution of 2. The membrane grafted had fluxes of 8.7 L/m2h and a rejection value of 96.2%. The atomic force showed the pristine membranes have a high surface roughness. The surfaces of the grafted membrane became smoother and anti-fouling surfaces image

Nanocomposite reverse osmosis (RO) membranes were developed using cellulose acetate (CA) and various amounts of the carboxylated multiwalled carbon nanotubes (CMWCNTs) via phase inversion procedure. The prepared membranes were investigated by Raman and infrared spectroscopies, transmission electron microscope (TEM), scanning electron microscope (SEM), atomic force microscope (AFM), and water contact angle measurement to deduce the structural, morphological, and hydrophilic properties. The incorporation of CMWCNTs improved the performance and the hydrophilicity of the CA-RO membranes. AFM images of pure CA-RO and modified CA-RO membranes with 0.059 wt% CMWCNTs revealed that the surface roughness values were 202 nm and 7.04 nm, respectively. The salt rejection and the permeate water flux of the membranes were measured at a high salt concentration of 10,000 ppm and high salinity of 35,000 ppm NaCl solution using the cross-flow technique. The performance of the nanocomposite membranes at the optimum addition of CMWCNTs (0.059 wt%) produced the highest salt rejection of 98.5%, and permeate water flux value of 5.85 l m −2 h −1 . At higher CMWCNTs concentrations (0.177 wt%), the salt rejection was declined to 76%.

Polypyrrole film was electrodeposited onto nickel alloy and stainless-steel substrates to be assessed as a supercapacitor electrode. Double layer supercapacitor electrodes were electrochemically characterized by electrochemical impedance spectroscopy, cyclic voltammetry, and charge/discharge. It was observed that the polypyrrole electrodeposited onto stainless steel and nickel alloy electrodes provided an outstanding specific capacitance of 1400 F/g and 1030 F/g and energy density of 583.33 Wh/kg and 429.16 Wh/kg, respectively. The electrode structure and morphological properties of polypyrrole films was studied by the scanning electron microscope.

Perovskite solar cells (PSCs) are believed to be one of a promising choice of the third-generation technology platforms to address the increasing green energy demands. The main objective of this work is to fabricate a hole transport layer (HTL) based on doped polyaniline (PANI) and graphene oxide with different ratios. This layer was characterized using Raman spectroscopy, scanning electron microscope (SEM), atomic force microscopy (AFM), UV–Visible spectroscopy, photoluminescence, contact angle, Hall effect and current density–voltage measurements. Photoluminescence confirmed that the HTL of PANI/GO with 1:0.5 ratio had the highest efficiency to extract hole carriers. The conductivity and carrier concentrations of this layer were increased with the addition of small amounts of GO up to 1:0.5 and declined at the high ratio of 1:1. The optimal performance of the fabricated inverted PSC using HTL of PANI/GO with 1:0.5 ratio had short-current density (Jsc), open circuit voltage (Voc), fill factor (FF) and efficiency of 21.23 mA/cm2, 0.52 V, 0.67 and 9.24%, respectively.

In this work, electroplating is used to deposit platinum nanoparticles (Pt NPs) on a transparent conductive oxide substrate (TCO glass) as an alternative simple and low-cost technique compared to sputtering. The used platinum salt is cost effective, and a general purpose grade can be used for large-scale manufacturing. In order to study the effects of deposition method of platinum on the electrode performance, two electrochemical deposition techniques are investigated (chronoamperometry and cyclic voltammetery) to deposit platinum using the same initial materials. Also, the effect of modifying the platinum counter electrode surface by deposition of a graphite thin layer by simple technique was investigated. Finally, Pt(NPs) and Pt(NPs)/graphite electrodes were used to assemble dye sensitized solar cells (DSSCs), and the cell with structure [TCO/TiO2/N719 Ru dye/electrolyte I3/I− redox/platinum NPs/graphite/TCO] yields output photovoltaic parameters of open circuit voltage, current density, fill factor and the highest efficiency with values of 0.65 V, 29.2 mA/cm2, 0.41, 7.9%, respectively.

Aqueous extract of sunflower (Helianthus annuus) seeds was used as a novel environmental friendly additive to improve the performance and anti-biofouling properties of cellulose acetate reverse osmosis (RO) membranes. Modified membranes were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy, while the anti-biofouling properties were studied by water contact-angle measurements, water content measurements, and static protein adsorption. The effect of modification of the membrane on the salt rejection and water flux was studied using a cross-flow RO unit. The results indicated that modified membranes have lower contact angle accomplished with high water content. They showed limited adsorption of protein and microbes, in addition to increased salt rejection and water flux values.

Mineral scale is a major flow assurance problem in industrial water systems. The antiscale properties of sunflower (Helianthus annuus) seed extract for CaSO4 and BaSO4 scales were investigated using NACE and conductivity tests, respectively. Comparative studies between the extract and 1-hydroxyethane-1,1-diphosphonic acid (HEDP), as commercial antiscalants, were done. The results revealed that the inhibition of CaSO4 scales using sunflower seed extract reached 100%, while HEDP achieved a maximum inhibition of 88%. Moreover, the maximum inhibition of BaSO4 scale in the presence of the extract was 84% compared with 86% in the presence of HEDP. Also microscopic examination showed that both inhibitors modified CaSO4 and BaSO4 crystals.

Crystalline thin films of Bi-Te-Se were deposited onto well cleaned glass substrates (BK7 type) by the vacuum thermal evaporation technique at a pressure of 10(-3) Pa. Bulk samples were used as targets to evaporate the corresponding films. The internal microstructure of bulk samples and films were characterized by x-ray diffraction (XRD). Identifications of the microstructure and the surface morphology of the bulk and thin film samples were determined using scanning electron microscopy (SEM). Powder of the bulk alloys and the thin films of our products were observed to be polycrystalline in the form of hexagonal Bi2Se3 and Bi2Te3 structure. The material characteristic power factor of 74 mu W/mK(2) was observed as the maximum value of power factor obtained in our study, and that was for Bi2Te3 near room temperature. The dimensionless figure of merit (ZT) was estimated based on Seebeck coefficient and electrical conductivity measurements alongside with thermal conductivity estimations. ZT values of Bi2Se3 and Bi2Se1.5Te1.5 were significantly enhanced as temperature increased, whilst, ZT of Bi2Te3 exhibited an opposite behavior. A mechanical stress test was performed in order to investigate the suitability of our films for thermoelectric modulus.

An electrochemical method was used to prepare polyaniline (PANI) with hydrochloric acid as a dopant. This electroactive material was fabricated using electrically modified carbon coated Teflon electrodes with an area of 0.64 cm2 in 1 M HCl. PANI was electrochemically synthesized using cyclic voltammetry (CV) with a variable number of cycles, scan rates, and step sizes at potentials ranging from − 0.2 V to 0.8 V. Fabricated samples were tested using different electrochemical techniques including CV, differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The DPV and EIS measurements indicate a linear relationship between both the current peak and the charge transfer resistance (Rct) and pH. These measurements showed that the prepared electrochemical device can be used as a sensor for pH. Optimum preparation parameters were 30 cycles, 50 mV/s scan rate and 2 mV step size. A linear relationship between oxidation current and pH of the solution with a correlation coefficient of 0.97 in the range of 1–5 makes PANI a candidate to be used as a pH sensor.

A nanoparticles layer of bright nickel base was deposited on copper substrates using electrodeposition technique before spraying the paint. IR reflectance of the paint was found to be around 0.4 without bright nickel layer and the reflectance increased to 0.6 at a Ni layer thickness of 750nm. The efficiency of the constructed solar collectors using black paint and black paint combined with bright nickel was found to be better than black paint individually. After aging tests under high temperature, Bright nickel improved the stability of the absorber paint. The collector optical gain FR(τα) was lowered by 24.7% for the commercial paint and lowered by 19.3% for the commercial paint combined with bright nickel. The overall heat loss FR(UL) was increased by 3.3% for the commercial paint and increased by 2.7% for the commercial paint combined with bright nickel after the temperature aging test.

Cellulose diacetate (CDA) and cellulose triacetate (CTA) were extracted from Egyptian rice straw. Reverse osmosis (RO) membranes were prepared from this CDA using phase inversion technique. The structural, crystalline, morphological, and hydrophilic properties of the prepared membranes were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance ((HNMR)-H-1), X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle measurements, respectively. The NMR spectra revealed a degree of substitution of 2.8 for CTA and 1.75 for CDA. The values of water flux and salt rejection for CA-RO membrane without annealing, tested in 10,000ppm NaCl, were 7.1 L/m(2)h and 87.4%, respectively, while the water flux of 4.76 L/m(2)h and a salt rejection of 93.3% were obtained for the annealed CA-RO membrane at 14bar. The annealed CA-RO membranes showed an asymmetric structure with ridge-and-valley on the top layer and macrovoid structures in the support layer as revealed by SEM. The CA-RO membranes grafted with 15wt% of 2-acrylamidopropane-2-methyl sulfonic acid produced a salt rejection of 93.5% and a water flux of 8.3 L/m(2)h. It was concluded that both the annealing and grafting processes enhanced the performance of the CA-RO membranes.

Polymethylacrylate (PMA) nanofibers membranes are fabricated by electrospinning technique and applied to the polymer matrix in quasi-solid-state electrolytes for dye sensitized solar cells (DSSCs). There is no previous studies reporting the production of PMA nanofibers. The electrospinning parameters such as polymer concentration, applied voltage, feed rate, tip to collector distance and solvent were optimized. Electrospun PMA fibrous membrane with average fiber diameter of 350nm was prepared from a 10wt% solution of PMA in a mixture of acetone/N,N-dimethylacetamide (6:4v/v) at an applied voltage of 20kV. It was then activated by immersing it in 0.5M LiI, 0.05M I2, and 0.5M 4-tert-butylpyridine in 3-methoxyproponitrile to obtain the corresponding membrane electrolyte with an ionic conductivity of 2.4×10−3Scm−1 at 25°C. Dye sensitized solar cells (DSSCs) employing the quasi solid-state electrolyte have an open-circuit voltage (Voc) of 0.65V and a short circuit current (Jsc) of 6.5mAcm−2 and photoelectric energy conversion efficiency (η) of 1.4% at an incident light intensity of 100mWcm−2.

In this work a novel and straightforward pyroelectric infrared detector based on blend of dodecylbenzene sulfonic acid (DBSA) doped polyaniline (PANI) and polyvinylidene fluoride (PVDF) with different weight percentages of PANI was fabricated. The crystalline and morphological properties of this blend were characterized using X-ray diffraction and scanning electron microscope, respectively. It was found that doped PANI hinders alpha-phase while promotes the polar beta-phase formation of PVDF. The voltage responsivity (R-v), noise equivalent power (NEP), and specific detectivity (D*) of PANI/PVDF blend were measured in the range from 0.01 Hz to 1000 Hz using an electrical chopped circuit. The optimum values of Rv and D* were 157 V/W and 1.82 x 10(6) cm Hz(1/2)/W, respectively, while the minimum value of NEP was about 2.67 x 10(-7) W/root Hz for the blend of 10 wt.% of PANI. (C) 2016 Elsevier B.V. All rights reserved.

An important step of fabrication of selective DNA probe/receptor is the functionalization of semiconducting surfaces with a self-assembled monolayer (SAM) with an appropriate surface termination to interact with DNA. In this work, we studied an immobilization of single-strand DNA (ssDNA) onto self-assembly monolayer of both the heavily exploited aminopropyltriethoxy silane (APTES) and n-(2-aminoethyl)-11-aminoundecyltrimethoxysilane (NAATS), a bi-functional amino silane onto the surface of SiGe substrate. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) techniques were employed to characterize the silanization of SAMs on SiGe surface. The immobilization process was confirmed using fluorescence intensity measurements. The coverage values of APTES and NAATS SAMs were estimated to be 71.3 and 83 XPS% at 78°, respectively from the C/Ge ratio. Comparing the performance towards both specific and non-specific ssDNA complements for both silanes, it was observed that a higher selectivity and sensitivity was obtained by using NAATS SAM. This work highlighted the importance of SAM chain length by comparing one short alkyl chains, APTES with that long-chain counterpart, NAATS.

The main objective of this work is to synthesize CdTe quantum dots (QDs) conjugated with Concanavalin A (Con A) as a novel biosensor to be selective and specific for the detection of Lipopolysaccharide (LPS). In addition, the conjugated CdTe QDs-Con A was used as fluorescence labels to capture Serratia marcescens bacteria through the recognition between CdTe QDs-Con A and LPS of S. marcescens. The appearance of the lattice plans in the high resolution transmission electron photograph indicated a high crystalline with an average size of 4-5 nm for the CdTe QDs. The results showed that the relative fluorescence intensity of CdTe QDs-Con A decreased linearly with LPS concentration in the range from 10 to 90 fg/mL and with correlation coefficient (R(2)) equal to 0.9713. LPS surrounding the S. marcescens bacteria was bound to the CdTe QDs-Con A and leads to quenching of PL intensity. It was found that a good linear relationship between the relative PL intensity and the logarithmic of cell population of S. marcescens in range from 1×10 to 1×10(6) CFU/mL at pH 7 with R(2) of 0.952 was established.

Cobalt doped cadmium telluride (CdTe) quantum dots (QDs) were synthesized with different Co concentrations by using non-aqueous method. CoxCd1−xTe QDs were characterized using optical absorption and photoluminescence spectroscopy, X-ray diffraction and high resolution transmission electron microscopy (HRTEM). It was noted that Co2+ was incorporated CdTe QDs without any shift in the diffraction peaks. HRTEM images revealed that the CdTe QDs were regular spherical particles with an average diameter of ~3 nm for undoped CdTe QDs and the average size of 2, 5 and 15 % Co2+ doped CdTe QDs were 4, 6.5 and 2.8 nm, respectively. Magnetization recognized for 0, 2, 5 and 15 % cobalt doped CdTe QDs revealed a ferromagnetic signal and ferromagnetic hysteresis loop. For pristine CdTe QDs a weak ferromagnetism was attributed to the charge transfer between capping agent and host CdTe QDs. Co2+ doped CdTe QDs exhibit stronger ferromagnetism and magnetic parameters such as saturation magnetization, MS, remanence, MR, and coercivity, HC, of CoxCd1−xTe QDs were obtained from the hysteresis loops. It was found that with increasing the doping concentration of Co2+ in CdTe QDs up to 5 %, Ms increased.

In this work, polyanil ine (PANT) base-single wall carbon nanotubes (SWCNTs) composite counter electrode (CE) and N3 ruthenium dye sensitized TiO2, prepared using hydrothermal method, photoelectrode were assembled to form a dye sensitized solar cell (DSSC). Three different compositions (ITO/PANI, ITO/PANI-SWCNTs and ITO/PANI-SWCNTs-graphite) of counter electrodes were fabricated and used for constructing different DSSCs. The morphologies of PANT-SWCNTs counter electrode and TiO2 mesoporous film surfaces were investigated using scanning electron microscope (SEM). The electrical properties of the resultant solar cells were investigated by measuring the current density voltage (J-V) under illumination condition and impedance measurements. The photovoltaic cell characteristics, i.e., open circuit voltage (V-OC), short circuit current density (J(sc)), fill factor (FF) and energy conversion efficiency (eta) were evaluated under illumination and were found to be 530 mV, 12 mA/cm(2), 0.3 and 1.8%, respectively for ITO/PANI-SWCNTs/graphite/electrolyte/ TiO2-N3 dye/ITO heterostructure. The depositing of a graphite layer on the PANI/SWCNTs nanocomposite creates a novel structure for the counter electrode and enhances the photovoltaic cell efficiency by 80%. (C) 2014 The Electrochemical Society. All rights reserved.

Polyaniline nanofibers were prepared chemically in both emiraldine base (EB) and emiraldine salt (ES) forms. The composite of polyaniline emiraldine salt with single walled carbon nanotubes (SWCNTs) was developed. Electrochemical sensors based on polyaniline nanofibers and its composite have been developed for the detection of chloropyrifos. Chloropyrifos exhibits one well defined reduction peak. The maximum peak current was linearly related to chloropyrifos concentration in the range from 0.2 μM to 1.4 μM. It was found that the SWCNTs improved the sensitivity of the polyaniline base graphite electrode from 3.0 mA/μM for polyaniline base to 9.69 mA/μM for ES-SWCNTs composite electrode.

Infrared detection based on polymeric materials is continuously developed in order to be cheap and easy to processing and also having high pyroelectric coefficient to convert heat to electrical signal. PANI/DBSA was blended with polyvinylidene fluoride (PVDF) with different weight ratios to improve pyroelectric coefficient and electrical conductivity of PVDF. The temperature dependence of the electrical conductivity is measured in the range of 20-100 °C It was found that the pyroelectric coefficient increased from 1.5×10-8 C/m2 °C for pristine PVDF to 2.61×10-5 C/m2 °C at 25 wt.% PANI at 30 °C. The infrared detector circuit connected to the gate of a voltage follower JFET with high input impedance was designed to convert the high output impedance of the sensor into the output resistance. The output from the sensor and JFET is amplified in two stages of operational amplifier with high voltage gain with low noise.