Massoumeh Bagheri - Academia.edu (original) (raw)
Papers by Massoumeh Bagheri
Polymers for Advanced Technologies, Apr 12, 2019
Herein, three ionic liquid random copolymers (P) containing 1‐vinyl‐3‐butylimidazolium bromide (V... more Herein, three ionic liquid random copolymers (P) containing 1‐vinyl‐3‐butylimidazolium bromide (VBImBr) and methyl methacrylate (MMA) with various molar ratios were prepared using conventional free radical polymerization. Afterward, their corresponding chemically cross‐linked copolymers (XP) were formed similarly in the presence of polyethylene glycol dimethacrylate (PEGDMA). The synthesized copolymers were characterized using FT‐IR, 1H NMR, and GPC. Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results showed that the rigidity and thermal stability of the copolymers depended on the ionic liquid content as well as the degree of cross‐linking. Gel polymer electrolytes were then prepared via obtained copolymers in the presence of a constant amount of synthesized imidazolium‐based ionic liquid. Among the copolymers, the P3 with in feed VBImBr:MMA molar ratio of 70:30 and the cross‐linked 1%‐XP3 copolymer prepared with 1 mol% of PEGDMA exhibited the highest conductivity and diffusion coefficients for I3¯ and I¯. The power conversion efficiency of the optimized linear and cross‐linked copolymers (P3 and 1%‐XP3) under the simulated AM 1.5 solar spectrum irradiation at 100 mW cm−2 were 3.49 and 4.13% in the fabricated dye‐sensitized solar cells (DSSCs), respectively. The superior long‐term stability and high performance of the gel electrolyte containing 1%‐XP3 suggested it as commercial gel electrolyte for future DSSCs.
Journal of Polymer Research, Mar 1, 2012
Well-defined side-chain liquid crystalline star-shaped polymers were synthesized with a combinati... more Well-defined side-chain liquid crystalline star-shaped polymers were synthesized with a combination of the ''core-first'' method and atom transfer radical polymerization (ATRP). Firstly, the functionalized macroinitiator based on the a-Cyclodextrins (a-CD) bearing functional bromide groups was synthesized, confirmed by 1 H-NMR, MALDI-TOF, and FTIR analysis. Secondly, the side-chain liquid crystalline arms poly[6-(4-methoxy-4-oxy-azobenzene) hexyl methacrylate] (PMMAzo) were prepared by ATRP. The characterization of the star polymers were performed with 1 H-NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM). It was found that the liquid crystalline behavior of the star polymer a-CD-PMMAzo n was similar to that of the linear homopolymer. The phase-transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased as the molecular weight increased for most of these samples. All star-shaped polymers show photoresponsive isomerization under the irradiation with Ultraviolet light. V
Molecular Crystals and Liquid Crystals, 2013
Iranian Polymer Journal, Feb 19, 2013
In order to investigate the effects of cholesteryl pendant groups on inducing liquid crystalline ... more In order to investigate the effects of cholesteryl pendant groups on inducing liquid crystalline (LC) phase formation, a new series of cholesteryl-modified poly (monomethyl itaconate) (PMMI-Chol-C 6) have been synthesized from poly(monomethyl itaconate) (PMMI) and 6-(cholesteryloxycarbonyloxy) hexanol (Chol-C 6) with different degrees of substitution (DS chol). All the obtained compounds were characterized by conventional spectroscopic methods. The DS chol values of the modified PMMI were obtained by 1 H NMR spectroscopy and conductometric titration. The inherent viscosities of polymers were determined by an Ubbelohde viscometer at 35°C in DMSO solution. The resulting products of modified PMMA polymers were soluble in a variety of organic solvents, and the solubility improved by increasing the DS chol. Thermal behavior and optical properties of Chol-C 6 and PMMI-Chol-C 6 polymers were investigated by thermal gravimetric analysis, differential scanning calorimetry and hot-stage polarizing optical microscopy. The glass transitions of the modified PMMI polymers occurred at lower temperatures than the parent PMMI. It was found that among the synthesized polymers with different molar ratios of the substitution, only the PMMI-Chol-C 6 (1) polymer bearing 77 mol% of the side chains, with reduced melting point and increased thermal stability, formed thermotropic liquid crystalline smectic phases. This polymer exhibited wider mesophase than the mesogenic side chain Chol-C 6 and amorphous morphology. The results of a comparative study on the structure and properties of the polymers showed that liquid crystalline polymers may be achieved through the attachment of mesogenic cholesterol side chain onto the main chain via methylene chains of side branches.
Iranian Polymer Journal, Jan 29, 2013
Journal of Polymer Research, Jan 23, 2013
ABSTRACT
Reactive & Functional Polymers, Feb 1, 2008
ABSTRACT
Reactive & Functional Polymers, Feb 1, 2008
Electrochimica Acta, 2010
ABSTRACT A series of new poly(1-vinyl-3-alkylimidazolium) iodide polymers with different alkyl de... more ABSTRACT A series of new poly(1-vinyl-3-alkylimidazolium) iodide polymers with different alkyl derivatives such as methyl, propyl and perflurodecyl have been synthesized. The alkyl substituent influenced some properties such as solubility, thermal stability, glass transition and crystallinity of the polymers. For instance, polymer having the propyl substituent was soluble in solvents of intermediate polarity such as acetonitrile, chloroform and THF, the one with the methyl substituent was only soluble in very polar solvents such as water and methanol and the fluorinated polymer was only soluble in DMF. The alkyl substituent also influenced the thermal stability in the order methyl > propyl > perflurodecyl and all the polymers thermally decomposed between 250 and 400 °C in nitrogen. The poly(1-vinyl-3-alkyl-imidazolium) iodide polymers having propyl and methyl substituents were amorphous polymers showing a glass transition temperature of 43 and 21 °C, respectively; and perflurodecyl polymers were semi-crystalline with a Tm at 153 °C and a Tg at 20 °C, as indicated by differential scanning calorimetry.Polymer electrolytes were formulated as mixtures of the ionic liquid 1-methyl-3-propylimidazolium iodide and the poly(1-vinyl-3-alkylimidazolium) iodide polymers. These polymer electrolytes showed ionic conductivities in the range of 10−3 to 10−7 S/cm at room temperature which strongly depended on the ionic liquid content. Finally, poly(1-vinyl-3-propyl-imidazolium) iodide was used to obtain gel electrolytes by adding it to a typical acetonitrile electrolyte used in dye sensitized solar cells (DSSCs). Solar cells with 1 cm2 area prepared using the polymer gel electrolyte yielded a maximum light-to-electricity conversion efficiency of 3.73%.
Polymer Science, Series B
Journal of Polymer Research, 2015
The objective of this study was the synthesis of copolymer networks based on poly (ε-caprolactone... more The objective of this study was the synthesis of copolymer networks based on poly (ε-caprolactone) (PCL), hydroxypropyl cellulose (HPC) and hexamethylene diisocyanate (HDI) via bulk graft copolymerization followed by crosslinking (using routes I and II), and subsequent optimization of the process by response surface methodology (RSM). The studied reaction parameters were: (i) monomer content (weight ratio of CL/HPC), (ii) amount of catalyst, and (iii) amount of crosslinker. FT-IR and 1 H NMR results confirmed that the grafting of PCL onto HPC and subsequent crosslinking through terminal hydroxyl groups of PCL grafts by HDI were performed successfully. Through differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD), it was found that the crystallinity of grafted polymers depended on the amount of grafted PCL and degree of crosslinking. In modeling of the process using RSM, the coefficient of determination (R 2) for the models (97.3 and 93.3 % for two routes) as well as the probability (p<0.0001) revealed high significance of the regression models. Also it was found that the obtained systems possessed T m s between 42.94 and 54.57°C (route I) and 32.49-46.30°C (route II) that were tunable by the monomer content, catalyst and crosslinker amounts. RSM provided a useful tool to select in a fast way the proper experimental conditions to synthesize crossinked HPC-g-PCL copolymer as a novel biocompatible and biodegradable shape memory polymer with adjustable switching temperature and potential biomedical applications, which would be further studied in the future.
علوم و تکنولوژی پلیمر, 2013
The rapidly increasing interest in functional materials with reversibly switchable physico- chemi... more The rapidly increasing interest in functional materials with reversibly switchable physico- chemical properties has led to significant work on the development of stimuli responsive membranes. Thermotropic liquid crystals with their exceptional properties have potentials for drug-delivery applications. Thermoresponsive liquid-crystal-embedded membranes were investigated for the purpose of developing the drug delivery systems with thermal stimuli response. Drug release occurs at temperatures above the phase transition temperature of thermotropic liquid crystals. Therefore, they can control drug release in response to small temperature changes. In this work, the biocompatible and thermotropic liquid crystalline polymer cholesteryl-(L-lactic acid)n ,CLAn (n=30), was synthesized with accurate control of molecular weight via ring opening polymerization method. Polymerization of L-lactide was carried out in the presence of cholesterol as an initiator and catalytic amount of tin (II) octoat...
Key Words shape memory polymer, temperature sensitive polymer, shape memory transition temperatur... more Key Words shape memory polymer, temperature sensitive polymer, shape memory transition temperature, magnetic nanoparticle, biodegradability Polymerization Quarterly, 2017 Volume 7, Number 3 Pages 86-97 S hape memory polymers been developed in the past years as a valid alternative to more traditional shape-memory materials. Shape memory polymers belong to a class of very smart materials that have the ability to remember their original shape. This advanced functionality makes shape memory polymer suitable and promising materials for diverse technological applications, including sensors and actuators particularly including the fabrication of smart biomedical devices. The polymers deform into a temporary shape and returns to its original shape by external environmental stimuli such as chemicals, temperature or pH. Therefore, a temperature-sensitive shape memory polymer is one that undergoes a structural change at a certain temperature called the transition temperature. A change in shape...
Key Words shape-memory polymers, stimuli-responsive, biomedical application, biocompatible, biode... more Key Words shape-memory polymers, stimuli-responsive, biomedical application, biocompatible, biodegradable Polymerization Quarterly, 2016 Volume 6, Number 1 Pages 33-42 S hape-memory polymers)SMPs) are an important class of intelligent materials which have attracted much attention in recent years, due to their prominent characteristics such as light weight, high recovery strain, low cost and ease of fabrication compared to shape-memory alloys. Shape-memory polymers can be deformed and fixed into a temporary shape, and recover their original permanent shape only upon asmall variation in environmental conditions such as heat, electric field, magnetic field, pH, light, ions, solvent, sonic field, enzyme, water and etc. This capability results from a combination of the polymer structure and the polymer morphology together with the applied processing and programming technology which is simply termed asshape-memory effect)SME). Polymers that exhibit SME are an important class of materials ...
Iranian Polymer Journal, 2022
A highly efficient poly( N -vinyl imidazole)/nitrogen-doped graphene quantum dot nanocomposite hy... more A highly efficient poly( N -vinyl imidazole)/nitrogen-doped graphene quantum dot nanocomposite hydrogel is designed for the adsorptive removal of cadmium, nickel, and chromium ions from aqueous solution. The nanocomposite hydrogels were synthesized through free-radical polymerization of N -vinyl imidazole (VI) and simultaneous cross linking by an imidazolium-based ionic liquid (DIL) with constant molar ratio of VI/DIL = 24 in the presence of nitrogen-doped graphene quantum dots (NGQD) (0.9% and 4.0% by weights) in an aqueous media. The maximum swelling degree and improved morphological features were achieved for NGQDs at its highest content, and that was used in the removal of three cations from aqueous solution. FTIR, DSC, XRD and SEM equipped with energy dispersive X-ray spectroscopy analysis were used to characterize the structure and surface morphology of the adsorbent before and after adsorption process. The effects of pH, initial concentrations of ions and contact time on the adsorption capacity of composite hydrogels were optimized. The removal efficiencies for Cd(II), Ni(II) and Cr(VI) ions were found to be 75.1%, 94.6% and 70.8% at pH 7.0, optimal ion concentration of 1000 mg/L and at contact times of 40, 45 and 180 min, respectively. The adsorption kinetics and isotherm models showed that the process was better explained by pseudo-first-order kinetics and the Langmuir isotherm model. From the model, the maximum adsorption capacities for Cd(II), Ni(II) and Cr(VI) ions were found to be 500, 555 and 357 mg/g, respectively. The results suggested that the developed nanocomposite hydrogel can effectively be used for the adsorption removal of studied metal ions. Graphical abstract
liquid crystalline polymers; thermotropic polyurethanes; mesogenic side group; optical texture; D... more liquid crystalline polymers; thermotropic polyurethanes; mesogenic side group; optical texture; DSC. To whom correspondence to be addressed.
Key Words amphiphilic polymer, azo polymer, photoresponsive, azobenzene, self-assembly Polymeriza... more Key Words amphiphilic polymer, azo polymer, photoresponsive, azobenzene, self-assembly Polymerization Quarterly, 2016 Volume 6, Number 4 Pages 81-93 M ost interesting properties of azo polymers are directly related with the trans-cis photoisomerization of the azobenzene units present in their polymer structure. Trans-cis isomerization of azobenzene and its derivatives has been intensively investigated theoretically and experimentally. Amphiphilic azo polymers can combine the photoresponsive properties of azo polymers with the self-assembling characteristics of amphiphilic polymers. The polymers show ability to form ultra-thin films, ordered phase-separation structure in bulk, micelle, vesicles, and other aggregates containing azobenzene moieties through self-assembly. Unique photoresponsive properties related with the self-assembled structures of azo polymers have been observed and explored for potential applications. Research works have demonstrated that light irradiation manifests...
The authors have requested that this preprint be removed from Research Square.
Journal of Materials Science: Materials in Electronics, 2019
In this study, graphene quantum dots (GQDs) functionalized with ionic liquid (IL) were introduced... more In this study, graphene quantum dots (GQDs) functionalized with ionic liquid (IL) were introduced as an efficient quasi-solid-state hybrid electrolyte for dye-sensitized solar cells. The GQDs have been covalently functionalized with imidazolium-based IL (GQDs-IL), and the resulted hybrid electrolyte has been characterized by FT-IR, 1 H- and 13 C-NMR, XRD, fluorescence spectroscopy, zeta potential and thermogravimetric analysis. The power conversion efficiency of the prepared electrolytes from GQDs, IL and GQDs-IL under the simulated AM 1.5 solar spectrum irradiation at 100 mW cm −2 in the fabricated dye-sensitized solar cells (DSSCs) was found to be 2.24, 4.52 and 4.58% respectively. The short-circuit current density of the DSSC with GQDs-IL-based electrolyte was calculated to be 19.57 mA cm −2 which was remarkably more than GQDs and IL. According to Bode plots, the use of GQDs in the final electrolyte increased the electron life time and reduced the recombination reaction to the redox couple due to the inhibition of the back-electron transfer to the electrolyte. Upon the superior long-term stability and highest photoelectric conversion efficiency of the developed GQDs-IL electrolyte, the fabricated DSSCs could overcome the drawbacks of volatile liquid electrolytes.
Polymer Bulletin, 2018
The present work studies the adsorptive removal of methylene blue (MB) dye from aqueous solution ... more The present work studies the adsorptive removal of methylene blue (MB) dye from aqueous solution using a novel biocompatible adsorbent based on hydroxypropyl cellulose (HPC) and itaconic acid nanogels. The biocompatible adsorbent was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and dynamic light scattering analyses. Response surface methodology was used to modeling and optimization of the adsorption process. A second-order empirical relationship between adsorption capacity and independent variables (pH of the solution, contact time and dye concentration) was obtained. The results of design of experiments demonstrated that the predicted values were well fitted with the experimental data where coefficient of determination (R 2) equaled 0.9861. Pareto analysis for identification of the factors effect on the system revealed that the initial concentration of MB was the most effective parameter. Maximum removal efficiency (99.9%) was achieved at optimum parameters where pH, MB concentration, and contact time were 5.6, 130 mg L −1 , and 5 min, respectively. Furthermore, the adsorption experimental data were well fitted to the Temkin isotherm and pseudosecond-order kinetic model. Consequently, it was found out that the HPC-PIA nanogels with high adsorption capacity (nearly 761 mg g −1) can be a suitable adsorbent for removal of cationic dyes from textile colored wastewaters.
Polymers for Advanced Technologies, Apr 12, 2019
Herein, three ionic liquid random copolymers (P) containing 1‐vinyl‐3‐butylimidazolium bromide (V... more Herein, three ionic liquid random copolymers (P) containing 1‐vinyl‐3‐butylimidazolium bromide (VBImBr) and methyl methacrylate (MMA) with various molar ratios were prepared using conventional free radical polymerization. Afterward, their corresponding chemically cross‐linked copolymers (XP) were formed similarly in the presence of polyethylene glycol dimethacrylate (PEGDMA). The synthesized copolymers were characterized using FT‐IR, 1H NMR, and GPC. Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results showed that the rigidity and thermal stability of the copolymers depended on the ionic liquid content as well as the degree of cross‐linking. Gel polymer electrolytes were then prepared via obtained copolymers in the presence of a constant amount of synthesized imidazolium‐based ionic liquid. Among the copolymers, the P3 with in feed VBImBr:MMA molar ratio of 70:30 and the cross‐linked 1%‐XP3 copolymer prepared with 1 mol% of PEGDMA exhibited the highest conductivity and diffusion coefficients for I3¯ and I¯. The power conversion efficiency of the optimized linear and cross‐linked copolymers (P3 and 1%‐XP3) under the simulated AM 1.5 solar spectrum irradiation at 100 mW cm−2 were 3.49 and 4.13% in the fabricated dye‐sensitized solar cells (DSSCs), respectively. The superior long‐term stability and high performance of the gel electrolyte containing 1%‐XP3 suggested it as commercial gel electrolyte for future DSSCs.
Journal of Polymer Research, Mar 1, 2012
Well-defined side-chain liquid crystalline star-shaped polymers were synthesized with a combinati... more Well-defined side-chain liquid crystalline star-shaped polymers were synthesized with a combination of the ''core-first'' method and atom transfer radical polymerization (ATRP). Firstly, the functionalized macroinitiator based on the a-Cyclodextrins (a-CD) bearing functional bromide groups was synthesized, confirmed by 1 H-NMR, MALDI-TOF, and FTIR analysis. Secondly, the side-chain liquid crystalline arms poly[6-(4-methoxy-4-oxy-azobenzene) hexyl methacrylate] (PMMAzo) were prepared by ATRP. The characterization of the star polymers were performed with 1 H-NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM). It was found that the liquid crystalline behavior of the star polymer a-CD-PMMAzo n was similar to that of the linear homopolymer. The phase-transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased as the molecular weight increased for most of these samples. All star-shaped polymers show photoresponsive isomerization under the irradiation with Ultraviolet light. V
Molecular Crystals and Liquid Crystals, 2013
Iranian Polymer Journal, Feb 19, 2013
In order to investigate the effects of cholesteryl pendant groups on inducing liquid crystalline ... more In order to investigate the effects of cholesteryl pendant groups on inducing liquid crystalline (LC) phase formation, a new series of cholesteryl-modified poly (monomethyl itaconate) (PMMI-Chol-C 6) have been synthesized from poly(monomethyl itaconate) (PMMI) and 6-(cholesteryloxycarbonyloxy) hexanol (Chol-C 6) with different degrees of substitution (DS chol). All the obtained compounds were characterized by conventional spectroscopic methods. The DS chol values of the modified PMMI were obtained by 1 H NMR spectroscopy and conductometric titration. The inherent viscosities of polymers were determined by an Ubbelohde viscometer at 35°C in DMSO solution. The resulting products of modified PMMA polymers were soluble in a variety of organic solvents, and the solubility improved by increasing the DS chol. Thermal behavior and optical properties of Chol-C 6 and PMMI-Chol-C 6 polymers were investigated by thermal gravimetric analysis, differential scanning calorimetry and hot-stage polarizing optical microscopy. The glass transitions of the modified PMMI polymers occurred at lower temperatures than the parent PMMI. It was found that among the synthesized polymers with different molar ratios of the substitution, only the PMMI-Chol-C 6 (1) polymer bearing 77 mol% of the side chains, with reduced melting point and increased thermal stability, formed thermotropic liquid crystalline smectic phases. This polymer exhibited wider mesophase than the mesogenic side chain Chol-C 6 and amorphous morphology. The results of a comparative study on the structure and properties of the polymers showed that liquid crystalline polymers may be achieved through the attachment of mesogenic cholesterol side chain onto the main chain via methylene chains of side branches.
Iranian Polymer Journal, Jan 29, 2013
Journal of Polymer Research, Jan 23, 2013
ABSTRACT
Reactive & Functional Polymers, Feb 1, 2008
ABSTRACT
Reactive & Functional Polymers, Feb 1, 2008
Electrochimica Acta, 2010
ABSTRACT A series of new poly(1-vinyl-3-alkylimidazolium) iodide polymers with different alkyl de... more ABSTRACT A series of new poly(1-vinyl-3-alkylimidazolium) iodide polymers with different alkyl derivatives such as methyl, propyl and perflurodecyl have been synthesized. The alkyl substituent influenced some properties such as solubility, thermal stability, glass transition and crystallinity of the polymers. For instance, polymer having the propyl substituent was soluble in solvents of intermediate polarity such as acetonitrile, chloroform and THF, the one with the methyl substituent was only soluble in very polar solvents such as water and methanol and the fluorinated polymer was only soluble in DMF. The alkyl substituent also influenced the thermal stability in the order methyl > propyl > perflurodecyl and all the polymers thermally decomposed between 250 and 400 °C in nitrogen. The poly(1-vinyl-3-alkyl-imidazolium) iodide polymers having propyl and methyl substituents were amorphous polymers showing a glass transition temperature of 43 and 21 °C, respectively; and perflurodecyl polymers were semi-crystalline with a Tm at 153 °C and a Tg at 20 °C, as indicated by differential scanning calorimetry.Polymer electrolytes were formulated as mixtures of the ionic liquid 1-methyl-3-propylimidazolium iodide and the poly(1-vinyl-3-alkylimidazolium) iodide polymers. These polymer electrolytes showed ionic conductivities in the range of 10−3 to 10−7 S/cm at room temperature which strongly depended on the ionic liquid content. Finally, poly(1-vinyl-3-propyl-imidazolium) iodide was used to obtain gel electrolytes by adding it to a typical acetonitrile electrolyte used in dye sensitized solar cells (DSSCs). Solar cells with 1 cm2 area prepared using the polymer gel electrolyte yielded a maximum light-to-electricity conversion efficiency of 3.73%.
Polymer Science, Series B
Journal of Polymer Research, 2015
The objective of this study was the synthesis of copolymer networks based on poly (ε-caprolactone... more The objective of this study was the synthesis of copolymer networks based on poly (ε-caprolactone) (PCL), hydroxypropyl cellulose (HPC) and hexamethylene diisocyanate (HDI) via bulk graft copolymerization followed by crosslinking (using routes I and II), and subsequent optimization of the process by response surface methodology (RSM). The studied reaction parameters were: (i) monomer content (weight ratio of CL/HPC), (ii) amount of catalyst, and (iii) amount of crosslinker. FT-IR and 1 H NMR results confirmed that the grafting of PCL onto HPC and subsequent crosslinking through terminal hydroxyl groups of PCL grafts by HDI were performed successfully. Through differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD), it was found that the crystallinity of grafted polymers depended on the amount of grafted PCL and degree of crosslinking. In modeling of the process using RSM, the coefficient of determination (R 2) for the models (97.3 and 93.3 % for two routes) as well as the probability (p<0.0001) revealed high significance of the regression models. Also it was found that the obtained systems possessed T m s between 42.94 and 54.57°C (route I) and 32.49-46.30°C (route II) that were tunable by the monomer content, catalyst and crosslinker amounts. RSM provided a useful tool to select in a fast way the proper experimental conditions to synthesize crossinked HPC-g-PCL copolymer as a novel biocompatible and biodegradable shape memory polymer with adjustable switching temperature and potential biomedical applications, which would be further studied in the future.
علوم و تکنولوژی پلیمر, 2013
The rapidly increasing interest in functional materials with reversibly switchable physico- chemi... more The rapidly increasing interest in functional materials with reversibly switchable physico- chemical properties has led to significant work on the development of stimuli responsive membranes. Thermotropic liquid crystals with their exceptional properties have potentials for drug-delivery applications. Thermoresponsive liquid-crystal-embedded membranes were investigated for the purpose of developing the drug delivery systems with thermal stimuli response. Drug release occurs at temperatures above the phase transition temperature of thermotropic liquid crystals. Therefore, they can control drug release in response to small temperature changes. In this work, the biocompatible and thermotropic liquid crystalline polymer cholesteryl-(L-lactic acid)n ,CLAn (n=30), was synthesized with accurate control of molecular weight via ring opening polymerization method. Polymerization of L-lactide was carried out in the presence of cholesterol as an initiator and catalytic amount of tin (II) octoat...
Key Words shape memory polymer, temperature sensitive polymer, shape memory transition temperatur... more Key Words shape memory polymer, temperature sensitive polymer, shape memory transition temperature, magnetic nanoparticle, biodegradability Polymerization Quarterly, 2017 Volume 7, Number 3 Pages 86-97 S hape memory polymers been developed in the past years as a valid alternative to more traditional shape-memory materials. Shape memory polymers belong to a class of very smart materials that have the ability to remember their original shape. This advanced functionality makes shape memory polymer suitable and promising materials for diverse technological applications, including sensors and actuators particularly including the fabrication of smart biomedical devices. The polymers deform into a temporary shape and returns to its original shape by external environmental stimuli such as chemicals, temperature or pH. Therefore, a temperature-sensitive shape memory polymer is one that undergoes a structural change at a certain temperature called the transition temperature. A change in shape...
Key Words shape-memory polymers, stimuli-responsive, biomedical application, biocompatible, biode... more Key Words shape-memory polymers, stimuli-responsive, biomedical application, biocompatible, biodegradable Polymerization Quarterly, 2016 Volume 6, Number 1 Pages 33-42 S hape-memory polymers)SMPs) are an important class of intelligent materials which have attracted much attention in recent years, due to their prominent characteristics such as light weight, high recovery strain, low cost and ease of fabrication compared to shape-memory alloys. Shape-memory polymers can be deformed and fixed into a temporary shape, and recover their original permanent shape only upon asmall variation in environmental conditions such as heat, electric field, magnetic field, pH, light, ions, solvent, sonic field, enzyme, water and etc. This capability results from a combination of the polymer structure and the polymer morphology together with the applied processing and programming technology which is simply termed asshape-memory effect)SME). Polymers that exhibit SME are an important class of materials ...
Iranian Polymer Journal, 2022
A highly efficient poly( N -vinyl imidazole)/nitrogen-doped graphene quantum dot nanocomposite hy... more A highly efficient poly( N -vinyl imidazole)/nitrogen-doped graphene quantum dot nanocomposite hydrogel is designed for the adsorptive removal of cadmium, nickel, and chromium ions from aqueous solution. The nanocomposite hydrogels were synthesized through free-radical polymerization of N -vinyl imidazole (VI) and simultaneous cross linking by an imidazolium-based ionic liquid (DIL) with constant molar ratio of VI/DIL = 24 in the presence of nitrogen-doped graphene quantum dots (NGQD) (0.9% and 4.0% by weights) in an aqueous media. The maximum swelling degree and improved morphological features were achieved for NGQDs at its highest content, and that was used in the removal of three cations from aqueous solution. FTIR, DSC, XRD and SEM equipped with energy dispersive X-ray spectroscopy analysis were used to characterize the structure and surface morphology of the adsorbent before and after adsorption process. The effects of pH, initial concentrations of ions and contact time on the adsorption capacity of composite hydrogels were optimized. The removal efficiencies for Cd(II), Ni(II) and Cr(VI) ions were found to be 75.1%, 94.6% and 70.8% at pH 7.0, optimal ion concentration of 1000 mg/L and at contact times of 40, 45 and 180 min, respectively. The adsorption kinetics and isotherm models showed that the process was better explained by pseudo-first-order kinetics and the Langmuir isotherm model. From the model, the maximum adsorption capacities for Cd(II), Ni(II) and Cr(VI) ions were found to be 500, 555 and 357 mg/g, respectively. The results suggested that the developed nanocomposite hydrogel can effectively be used for the adsorption removal of studied metal ions. Graphical abstract
liquid crystalline polymers; thermotropic polyurethanes; mesogenic side group; optical texture; D... more liquid crystalline polymers; thermotropic polyurethanes; mesogenic side group; optical texture; DSC. To whom correspondence to be addressed.
Key Words amphiphilic polymer, azo polymer, photoresponsive, azobenzene, self-assembly Polymeriza... more Key Words amphiphilic polymer, azo polymer, photoresponsive, azobenzene, self-assembly Polymerization Quarterly, 2016 Volume 6, Number 4 Pages 81-93 M ost interesting properties of azo polymers are directly related with the trans-cis photoisomerization of the azobenzene units present in their polymer structure. Trans-cis isomerization of azobenzene and its derivatives has been intensively investigated theoretically and experimentally. Amphiphilic azo polymers can combine the photoresponsive properties of azo polymers with the self-assembling characteristics of amphiphilic polymers. The polymers show ability to form ultra-thin films, ordered phase-separation structure in bulk, micelle, vesicles, and other aggregates containing azobenzene moieties through self-assembly. Unique photoresponsive properties related with the self-assembled structures of azo polymers have been observed and explored for potential applications. Research works have demonstrated that light irradiation manifests...
The authors have requested that this preprint be removed from Research Square.
Journal of Materials Science: Materials in Electronics, 2019
In this study, graphene quantum dots (GQDs) functionalized with ionic liquid (IL) were introduced... more In this study, graphene quantum dots (GQDs) functionalized with ionic liquid (IL) were introduced as an efficient quasi-solid-state hybrid electrolyte for dye-sensitized solar cells. The GQDs have been covalently functionalized with imidazolium-based IL (GQDs-IL), and the resulted hybrid electrolyte has been characterized by FT-IR, 1 H- and 13 C-NMR, XRD, fluorescence spectroscopy, zeta potential and thermogravimetric analysis. The power conversion efficiency of the prepared electrolytes from GQDs, IL and GQDs-IL under the simulated AM 1.5 solar spectrum irradiation at 100 mW cm −2 in the fabricated dye-sensitized solar cells (DSSCs) was found to be 2.24, 4.52 and 4.58% respectively. The short-circuit current density of the DSSC with GQDs-IL-based electrolyte was calculated to be 19.57 mA cm −2 which was remarkably more than GQDs and IL. According to Bode plots, the use of GQDs in the final electrolyte increased the electron life time and reduced the recombination reaction to the redox couple due to the inhibition of the back-electron transfer to the electrolyte. Upon the superior long-term stability and highest photoelectric conversion efficiency of the developed GQDs-IL electrolyte, the fabricated DSSCs could overcome the drawbacks of volatile liquid electrolytes.
Polymer Bulletin, 2018
The present work studies the adsorptive removal of methylene blue (MB) dye from aqueous solution ... more The present work studies the adsorptive removal of methylene blue (MB) dye from aqueous solution using a novel biocompatible adsorbent based on hydroxypropyl cellulose (HPC) and itaconic acid nanogels. The biocompatible adsorbent was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and dynamic light scattering analyses. Response surface methodology was used to modeling and optimization of the adsorption process. A second-order empirical relationship between adsorption capacity and independent variables (pH of the solution, contact time and dye concentration) was obtained. The results of design of experiments demonstrated that the predicted values were well fitted with the experimental data where coefficient of determination (R 2) equaled 0.9861. Pareto analysis for identification of the factors effect on the system revealed that the initial concentration of MB was the most effective parameter. Maximum removal efficiency (99.9%) was achieved at optimum parameters where pH, MB concentration, and contact time were 5.6, 130 mg L −1 , and 5 min, respectively. Furthermore, the adsorption experimental data were well fitted to the Temkin isotherm and pseudosecond-order kinetic model. Consequently, it was found out that the HPC-PIA nanogels with high adsorption capacity (nearly 761 mg g −1) can be a suitable adsorbent for removal of cationic dyes from textile colored wastewaters.