Displaying publications 21 - 40 of 255 in total

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  1. Fulltext Role of morphological structure, doping, and coating of different materials in the sensing characteristics of humidity sensors
    Tripathy A, Pramanik S, Cho J, Santhosh J, Osman NA
    Sensors (Basel), 2014 Sep 03;14(9):16343-422.
    PMID: 25256110 DOI: 10.3390/s140916343
    The humidity sensing characteristics of different sensing materials are important properties in order to monitor different products or events in a wide range of industrial sectors, research and development laboratories as well as daily life. The primary aim of this study is to compare the sensing characteristics, including impedance or resistance, capacitance, hysteresis, recovery and response times, and stability with respect to relative humidity, frequency, and temperature, of different materials. Various materials, including ceramics, semiconductors, and polymers, used for sensing relative humidity have been reviewed. Correlations of the different electrical characteristics of different doped sensor materials as the most unique feature of a material have been noted. The electrical properties of different sensor materials are found to change significantly with the morphological changes, doping concentration of different materials and film thickness of the substrate. Various applications and scopes are pointed out in the review article. We extensively reviewed almost all main kinds of relative humidity sensors and how their electrical characteristics vary with different doping concentrations, film thickness and basic sensing materials. Based on statistical tests, the zinc oxide-based sensing material is best for humidity sensor design since it shows extremely low hysteresis loss, minimum response and recovery times and excellent stability.
    Matched MeSH terms: Polymers/chemistry*
  2. New generation Amberlite XAD resin for the removal of metal ions: A review
    Ahmad A, Siddique JA, Laskar MA, Kumar R, Mohd-Setapar SH, Khatoon A, et al.
    J Environ Sci (China), 2015 May 1;31:104-23.
    PMID: 25968265 DOI: 10.1016/j.jes.2014.12.008
    The direct determination of toxic metal ions, in environmental samples, is difficult because of the latter's presence in trace concentration in association with complex matrices, thereby leading to insufficient sensitivity and selectivity of the methods used. The simultaneous removal of the matrix and preconcentration of the metal ions, through solid phase extraction, serves as the promising solution. The mechanism involved in solid phase extraction (SPE) depends on the nature of the sorbent and analyte. Thus, SPE is carried out by means of adsorption, ion exchange, chelation, ion pair formation, and so forth. As polymeric supports, the commercially available Amberlite resins have been found very promising for designing chelating matrices due to its good physical and chemical properties such as porosity, high surface area, durability and purity. This review presents an overview of the various works done on the modification of Amberlite XAD resins with the objective of making it an efficient sorbent. The methods of modifications which are generally based on simple impregnation, sorption as chelates and chemical bonding have been discussed. The reported results, including the preconcentration limit, the detection limit, sorption capacity, preconcentration factors etc., have been reproduced.
    Matched MeSH terms: Polymers/chemistry
  3. Fulltext Removal of toxic mercury from petroleum oil by newly synthesized molecularly-imprinted polymer
    Khairi NA, Yusof NA, Abdullah AH, Mohammad F
    Int J Mol Sci, 2015;16(5):10562-77.
    PMID: 26006226 DOI: 10.3390/ijms160510562
    In recent years, molecularly-imprinted polymers (MIPs) have attracted the attention of several researchers due to their capability for molecular recognition, easiness of preparation, stability and cost-effective production. By taking advantage of these facts, Hg(II) imprinted and non-imprinted copolymers were prepared by polymerizing mercury nitrate stock solution (or without it) with methacrylic acid (MAA), 2-hydroxyl ethyl methacrylate (HEMA), methanol and ethylene glycol dimethacrylate (EGDMA) as the monomer, co-monomer solvent (porogen) and cross-linker, respectively. Thus, the formed Hg(II) imprinted polymer was characterized by using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), Brunauer, Emmett and Teller (BET) and thermal gravimetric analysis (TGA). The separation and preconcentration characteristics of Hg(II) imprinted polymer were investigated by solid phase extraction (SPE) procedures, and an optimal pH of 7 was investigated as ideal. The specific surface area of the Hg(II) imprinted polymer was found to be 19.45 m2/g with a size range from 100 to 140 µm in diameter. The maximum adsorption capacity was observed to be 1.11 mg/g of Hg(II) imprinted beads with 87.54% removal of Hg(II) ions within the first 5 min. The results of the study therefore confirm that the Hg(II) imprinted polymer can be used multiple times without significantly losing its adsorption capacity.
    Matched MeSH terms: Polymers/chemistry*
  4. Simultaneous removal of potent cyanotoxins from water using magnetophoretic nanoparticle of polypyrrole: adsorption kinetic and isotherm study
    Hena S, Rozi R, Tabassum S, Huda A
    Environ Sci Pollut Res Int, 2016 Aug;23(15):14868-80.
    PMID: 27072032 DOI: 10.1007/s11356-016-6540-5
    Cyanotoxins, microcystins and cylindrospermopsin, are potent toxins produced by cyanobacteria in potable water supplies. This study investigated the removal of cyanotoxins from aqueous media by magnetophoretic nanoparticle of polypyrrole adsorbent. The adsorption process was pH dependent with maximum adsorption occurring at pH 7 for microcystin-LA, LR, and YR and at pH 9 for microcystin-RR and cylindrospermopsin (CYN). Kinetic studies and adsorption isotherms reflected better fit for pseudo-second-order rate and Langmuir isotherm model, respectively. Thermodynamic calculations showed that the cyanotoxin adsorption process is endothermic and spontaneous in nature. The regenerated adsorbent can be successfully reused without appreciable loss of its original capacity.
    Matched MeSH terms: Polymers/chemistry*
  5. Cytotoxicity evaluation of poly(ethylene) oxide nanofibre in MCF-7 breast cancer cell line
    Jamil M, Mustafa IS, Ahmed NM, Sahul Hamid SB
    Biomater Adv, 2022 Dec;143:213178.
    PMID: 36368056 DOI: 10.1016/j.bioadv.2022.213178
    Biocompatible polymers have received significant interest from researchers for their potential in diagnostic applications. This type of polymer can perform with an appropriate host response or carrier for a specific purpose. The current study aims to fabricate and characterise poly(ethylene) oxide (PEO) nanofibres with different concentrations for cytotoxicity evaluation in human breast cancer cell lines (MCF-7) and to get an optimal PEO nanofibre concentration (permissible limit) as a suitable polymer matrix or carrier with potential use in diagnostic applications. The fabrication of PEO nanofibres was done using electrospinning and was characterised by structure and morphology, surface roughness, chemical bonding and release profiles. The functional effects of PEO nanofibres were evaluated with MTS assay and colony formation assay in MCF-7 cells. The results showed that viscosity plays a vital role in synthesising a polymer solution in electrospinning for producing beadless nanofibrous mats ranging from 4.7 Pa·s to 77.7 Pa·s. As the PEO concentration increases, the nanofibre diameter and thickness will increase, but the surface roughness will be decreased. The average fibre diameter for 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 129 ± 70 nm, 185 ± 55 nm and 192 ± 53 nm, respectively. In addition, the fibre thickness for 4 wt% PEO, 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 269 ± 3 μm, 664 ± 4 μm, 758 ± 7 μm and 1329 ± 44 μm, respectively. Contrarily, the surface roughness for 4 wt% PEO, 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 55.6 ± 9 nm, 42.8 ± 6 nm, 42.7 ± 7 nm and 36.6 ± 1 nm, respectively. PEO nanofibres showed the same burst release pattern and rate due to the same molecular weight of PEO with a stable release rate profile after 15 min. It also demonstrates that the percentage of PEO nanofibre release increased with the increasing PEO concentration due to the fibre diameter and thickness. The findings showed that all PEO nanofibres formulations were non-toxic to MCF-7 cells. It is suggested that 5 wt% PEO nanofibre exhibited non-cytotoxic characteristics by maintaining the cell viability from dose 0-1000 μg/ml and did not induce the number of colonies. Therefore, 5 wt% PEO nanofibre is the optimal nanofibre concentration and was suggested as a suitable base polymer matrix or carrier with potential use for diagnostic purposes. The findings in this study have demonstrated the influence of cell growth and viability, including the effects of PEO nanofibre formulations on cancer progress characteristics to achieve a permissible PEO nanofibre concentration limit that can be a benchmark in medical applications, particularly diagnostic applications.
    Matched MeSH terms: Polymers/chemistry
  6. Poly-(ionic liquid) coated with magnetic nanoparticles for micro solid phase extraction of polycyclic aromatic hydrocarbons in food samples
    Muhammad Yunus F, Alias Y, Yahya N, Mohamad Zain NN, Raoov M
    Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2024 May;41(5):495-512.
    PMID: 38466777 DOI: 10.1080/19440049.2024.2326426
    Poly(methyl methacrylate-vinyl imidazole bromide) (poly-MMA-IL)-grafted magnetic nanoparticles were successfully developed and applied in the micro-magnetic solid phase extraction (μ-MSPE) for 16 types of polycyclic aromatic hydrocarbons (PAHs) from tea, fried food, and grilled food samples via gas chromatography flame ionization detector (GC-FID). One variable at a time (OVAT) and response surface methodology (RSM) were used for efficient optimization. The validation method showed a good coefficient of determination (R2) ranging from 0.9901 to 0.9982 (n = 3) with linearity of 0.2 μg L-1-500 μg L-1. Detection and quantification limits were 0.06 µg L-1-0.32 µg L-1 and 0.18 µg L-1-0.97 µg L-1. Additionally, satisfactory reproducibility was attained with intra-day and inter-day precisions having RSD ranges of 3.6%-11.1%. The spiked recovery value of 16 PAHs in fried food, grilled food and tea samples obtained from the night market in Malaysia ranged from 80%-12%, respectively.
    Matched MeSH terms: Polymers/chemistry
  7. Fulltext Heptamethine cyanine-based polymeric nanoparticles for photothermal therapy in HCT116 human colon cancer model
    Kampaengsri S, Yong GY, Aryamueang S, Ouengwanarat B, Pewklang T, Chansaenpak K, et al.
    Sci Rep, 2025 Jan 06;15(1):884.
    PMID: 39762372 DOI: 10.1038/s41598-024-83249-y
    In this work, we synthesize a quinoline-based heptamethine cyanine, QuCy7, with sulfonate groups to enhance water solubility. This dye demonstrates exceptional near-infrared absorption beyond 750 nm, accompanied by photothermal properties but low photostability. Encapsulating QyCy7 with polyethylene glycol to form nanopolymer, QuCy7@mPEG NPs, addresses the issue of its photoinstability. TEM showed that QuCy7@mPEG NPs possess a spherical morphology, featuring a core-shell structure with a size of around 120 nm in diameter. Upon irradiation with an 808 nm laser for 10 min, a significant increase in temperature up to 24 °C can be achieved with a photothermal conversion (PTC) rate of approximately 35%. QuCy7@mPEG NPs exhibit remarkable photothermal stability as compared to QuCy7. The efficiency of QuCy7@mPEG NPs was demonstrated by the in vitro PTT studies. Finally, the nanoparticles' acute toxicity and effectiveness were assessed using the chick embryo model. The results provide compelling evidence that QuCy7@mPEG NPs are safe without inducing hemolysis, inhibit angiogenesis when exposed to light, and exhibit anti-tumor activity with a 76% reduction in tumor size compared to QuCy7 (40%). Thus suggesting the sulfonate groups can enhance water solubility, and its nanopolymer is biocompatible and possesses superior anti-tumor efficacy.
    Matched MeSH terms: Polymers/chemistry
  8. Immobilization of Antibacterial Chlorhexidine on Biodegradable Polycaprolactone/Estradiol Electrospun Nanofibrous Membrane for Bone Regeneration
    Khrisna DF, Ambreen J, Wei TY, Riduan NAH, Daud NM, Zain NM, et al.
    J Biomed Mater Res B Appl Biomater, 2025 Apr;113(4):e35575.
    PMID: 40167028 DOI: 10.1002/jbm.b.35575
    Membrane-based scaffold for bone regeneration is vastly being explored to address issues that persist in defective bone regeneration, associated with infection and inflammation. This study focused on incorporating estradiol (E2) into biodegradable polycaprolactone (PCL) electrospun nanofibrous membrane, followed by the immobilization with antibacterial chlorhexidine (CHX) through the aid of a polydopamine (PDA) grafting layer. Several analyses including field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), wettability, biodegradation, drug release, antibacterial, and cytotoxicity analyses were conducted to study the physicochemical and biological properties of the membranes. The nanofibers were constructed with an average diameter of 1.32-1.33 μm and a porosity of 51%-53%, which is accommodating bone regeneration. The grafting of PDA was not only able to improve the surface wettability, which in turn allowed controllable degradability and sustained the release of E2 and CHX from the nanofibrous membranes. The immobilization of CHX on the PCL/E2 nanofibers has greatly retarded Gram-negative Escherichia coli compared to Gram-positive Staphylococcus aureus. The in vitro cytotoxicity assay statistically depicted the ability of the fabricated nanofibrous membranes to support cell proliferation without cytotoxic effects at the cell viability above 70%. These cumulative results indicate the potential development of CHX-immobilized PCL/E2 membrane as an alternative strategy to resolve bone regeneration issues.
    Matched MeSH terms: Polymers/chemistry
  9. Incorporation of graphene oxide/titanium dioxide with different polymer materials and its effects on methylene blue dye rejection and antifouling ability
    Mohamat R, Bakar SA, Mohamed A, Muqoyyanah M, Othman MHD, Mamat MH, et al.
    Environ Sci Pollut Res Int, 2023 Jun;30(28):72446-72462.
    PMID: 37170051 DOI: 10.1007/s11356-023-27207-7
    Exposure of synthetic dye, such as methylene blue (MB), in water bodies led to a serious threat to living things because they are toxic and non-degradable. Amongst the introduced dye removal methods, membrane separation process can be considered a powerful technique for treating dye contamination. However, this method commonly suffered from drawbacks, such as short membrane lifetime, low permeability and selectivity. To overcome these issues, graphene oxide (GO) and titanium dioxide (TiO2) were used as additives to fabricate polyethersulfone (PES)- and polyvinylidene fluoride (PVDF)-based hybrid membranes via non-solvent-induced phase separation method. Prior to membrane fabrication, GO was synthesised via electrochemical exfoliation method assisted by customised triple-tail surfactant. The potential of PES- and PVDF-based hybrid membranes for wastewater treatment has been discussed widely. However, direct comparison between these two polymeric membranes is not critically discussed for MB dye separation application yet. Therefore, this study is aimed at evaluating the performance of different types of polymers (e.g. PES and PVDF) in terms of membrane morphology, properties, dye rejection and antifouling ability. Results showed that the incorporation of GO and TiO2 alters the morphology of the fabricated membranes and affects dye rejection further, as well as their antifouling performance. In contrast with pristine membrane, PES-GO/TiO2 and PVDF-GO/TiO2 possessed high hydrophilicity, as indicated by their low contact angle (67.38° and 62.12°, respectively). Based on this study, PVDF-GO/TiO2 showed higher porosity value (94.88%), permeability (87.32 L/m2hMPa) and MB rejection rate (92.63%), as well as flux recovery ratio value of > 100% as compared with others. Overall, the incorporation of GO and TiO2 with PVDF polymer are proven to be effective hybrid materials of membrane fabrication for dye rejection application in the near future. The polymer material's intrinsic properties can affect the attributes of the fabricated membrane.
    Matched MeSH terms: Polymers/chemistry
  10. Theoretical Quantification of Cargo Effective Diffusivity in Affinity-Based Hydrogels
    Suthan R, Koo IK, Wang X, Goh KB
    Mol Pharm, 2026 Nov 02;23(11):5261-5271.
    PMID: 42969741 DOI: 10.1021/acs.molpharmaceut.6c00188
    Affinity hydrogels enable precise control of cargo release kinetics through specific, non-covalent interactions between the functionalized polymer network and therapeutic agents. Yet, how these interactions integrate with steric hindrance in the crosslinked network to determine cargo diffusivity, a critical kinetic parameter governing cargo-controlled release, remains poorly quantified. Here, we present a theoretical framework that explicitly bridges microscopic cargo-polymer interactions with macroscopic cargo release kinetics. Specifically, our approach delineates cargo diffusivity into two principal contributions: (i) binding interactions and (ii) steric hindrance, enabling a quantitative understanding of their interplay in defining cargo release performance. Increasing binding interactions, attractively, reduce diffusivity in a reverse sigmoidal fashion, transitioning from a steric- to a binding-controlled regime. Overall, we demonstrate how the interplay of microscopic forces governs cargo diffusivity within affinity hydrogels and, in turn, regulates cumulative cargo release at the macroscopic level, thereby bridging microscopic thermodynamic interactions with macroscopic cargo release kinetics, quantitatively.
    Matched MeSH terms: Polymers/chemistry
  11. A comprehensive review on polyelectrolyte complexes
    Meka VS, Sing MKG, Pichika MR, Nali SR, Kolapalli VRM, Kesharwani P
    Drug Discov Today, 2017 11;22(11):1697-1706.
    PMID: 28683256 DOI: 10.1016/j.drudis.2017.06.008
    Global research on polyelectrolytes at a fundamental and applied level is intensifying because the advantages of sustainability are being accepted in academia and industrial research settings. During recent decades, polyelectrolytes became one of the most attractive subjects of scientific research owing to their great potential in the areas of advanced technologies. Polyelectrolytes are a type of polymer that have multitudinous ionizable functional groups. Ionized polyelectrolytes in solution can form a complex with oppositely charged polyelectrolytes - a polyelectrolyte complex (PEC). The present article provides a comprehensive review on PECs and their classification, theory and characterization, as well as a critical analysis of the current research.
    Matched MeSH terms: Polymers/chemistry*
  12. Production of high molecular weight poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer by Cupriavidus malaysiensis USMAA1020 utilising substrate with longer carbon chain
    Huong KH, Elina KAR, Amirul AA
    Int J Biol Macromol, 2018 Sep;116:217-223.
    PMID: 29723627 DOI: 10.1016/j.ijbiomac.2018.04.148
    Long carbon chain alkanediols are used in the production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)], however these substrates possess high toxicity towards bacterial cells. This study demonstrated the effective utilisation of a long carbon chain alkanediol, namely 1,8-octanediol, to enhance the yield and production of a copolymer with a high molecular weight of over 1000 kDa, which is desirable for novel applications in medical and biopharmaceuticals. The increased PHA content (47-61 wt%) and concentration (1.7-4.5 g/L) was achieved by additional feeding of a combination of C4 substrates at C/N 10, with 1,8-octanediol + γ-butyrolactone producing P(3HB-co-22 mol% 4HB) with a high molecular weight (1060 kDa) and elongation at break of 970%. The DO-stat feeding strategy of C/N 10 has shown an increment of PHA concentration for both carbon combination, 0.45-4.27 g/L and 0.32-3.36 g/L for 1,8-octanediol + sodium 4-hydroxybutyrate (4HB-Na) and 1,8-octanediol + γ-butyrolactone, but with a slight reduction on molecular weight and mechanical strength. Nonetheless, further study revealed that a nitrogen-absence feeding strategy could retain the high molecular weight and elongation at break of the copolymer, and simultaneously improving the overall P(3HB-co-4HB) production.
    Matched MeSH terms: Polymers/chemistry*
  13. The effect of high UV radiation exposure environment on the novel PVC polymers
    Yousif E, Ahmed DS, Ahmed AA, Hameed AS, Muhamed SH, Yusop RM, et al.
    Environ Sci Pollut Res Int, 2019 Apr;26(10):9945-9954.
    PMID: 30739295 DOI: 10.1007/s11356-019-04323-x
    Although plastic induces environmental damages, almost the consumption of poly(vinyl chloride) never stops increasing. Therefore, this work abstracted by two parts, first, synthesis of Schiff bases 1-4 compounds through the reaction of amino group with appropriate aromatic aldehyde, reaction of PVC with Schiff bases compounds 1-4 in THF to form a new modified PVC-1, PVC-2, PVC-3, and PVC-4. The structures of Schiff bases 1-4 and the modified PVC-1, PVC-2, PVC-3, and PVC-4 have been characterized by different spectroscopic analyses. Second, the influence of introducing 4-amino-1,2,4-triazole as a pendent groups into PVC chain investigated on photostability rules of tests. The modified polymers photostability investigated by observing indices (ICO, Ipo, and IOH), weight loss, UV and morphological studies, and all results obtained indicated that PVC-1, PVC-2, PVC-3 and PVC-4 gave lower growth rate of ICO, IPO, and IOH through UV exposure time. The photostability are given as PVC-4 
    Matched MeSH terms: Polymers/chemistry
  14. Fulltext Synthesis, Characterization, and Application of Poly(4,4'-Cyclohexylidene Bisphenol Oxalate) for Solid-Phase Extraction of DNA
    Al Balawi AN, Yusof NA, Kamaruzaman S, Mohammad F, Wasoh H, Al Abbosh KF, et al.
    Biomed Res Int, 2019;2019:7064073.
    PMID: 30868072 DOI: 10.1155/2019/7064073
    The present study has synthesized poly(4,4'-cyclohexylidene bisphenol oxalate) by the condensation of oxalyl chloride with 4,4'-cyclohexylidene bisphenol, where its efficacy was tested for the solid-phase extraction of DNA. The synthesized polymer in the form of a white powder was characterized by FTIR, TGA-DTG, SEM, and BET analysis. The study utilized solid-phase application of the resulting polymer to extract DNA. The analysis of results provided the information that the extraction efficiency is a strong dependent of polymer amount and binding buffer type. Among the three types of buffers tested, the GuHCl buffer produced the most satisfactory results in terms of yield and efficiency of extraction. Moreover, the absorbance ratio of A260/A280 in all of the samples varied from 1.682 to 1.491, thereby confirming the capability of poly(4,4'-cyclohexylidene bisphenol oxalate) to elute pure DNA. The results demonstrated an increased DNA binding capacity with respect to increased percentage of the polymer. The study has concluded that poly(bisphenol Z oxalate) can be applied as one of the potential candidates for the high efficiency extraction of DNA by means of a simple, cost-effective, and environmentally friendly approach compared to the other traditional solid-phase methods.
    Matched MeSH terms: Polymers/chemistry
  15. Fulltext Synergy of the flow behaviour and disperse phase of cellulose nanoparticles in enhancing oil recovery at reservoir condition
    Agi A, Junin R, Arsad A, Abbas A, Gbadamosi A, Azli NB, et al.
    PLoS One, 2019;14(9):e0220778.
    PMID: 31560699 DOI: 10.1371/journal.pone.0220778
    Ascorbic acid was used for the first time to synthesize cellulose nanoparticles (CNP) extracted from okra mucilage. The physical properties of the CNP including their size distribution, and crystalline structures were investigated. The rheological properties of the cellulose nanofluid (CNF) were compared with the bulk okra mucilage and commercial polymer xanthan. The interfacial properties of the CNF at the interface of oil-water (O/W) system were investigated at different concentrations and temperatures. The effects of the interaction between the electrolyte and ultrasonic were determined. Core flooding experiment was conducted at reservoir condition to justify the effect of the flow behaviour and disperse phase behaviour of CNF on additional oil recovery. The performance of the CNF was compared to conventional EOR chemical. The combined method of ultrasonic, weak-acid hydrolysis and nanoprecipitation were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm, increased yield of 51% and preserved crystallinity respectively. The zeta potential result shows that the CNF was stable, and the surface charge signifies long term stability of the fluid when injected into oil field reservoirs. The CNF, okra and xanthan exhibited shear-thinning and pseudoplastic behaviour. The IFT decreased with increase in concentration of CNF, electrolyte and temperature. The pressure drop data confirmed the stability of CNF at 120°C and the formation of oil bank was enough to increase the oil recovery by 20%. CNF was found to be very effective in mobilizing residual oil at high-temperature high-pressure (HTHP) reservoir condition. The energy and cost estimations have shown that investing in ultrasonic-assisted weak-acid hydrolysis is easier, cost-effective, and can reduce energy consumption making the method economically advantageous compared to conventional methods.
    Matched MeSH terms: Polymers/chemistry
  16. Fulltext A Promising Polymer Blend Electrolytes Based on Chitosan: Methyl Cellulose for EDLC Application with High Specific Capacitance and Energy Density
    Aziz SB, Hamsan MH, Abdullah RM, Kadir MFZ
    Molecules, 2019 Jul 09;24(13).
    PMID: 31323966 DOI: 10.3390/molecules24132503
    In the present work, promising proton conducting solid polymer blend electrolytes (SPBEs) composed of chitosan (CS) and methylcellulose (MC) were prepared for electrochemical double-layer capacitor (EDLC) application with a high specific capacitance and energy density. The change in intensity and the broad nature of the XRD pattern of doped samples compared to pure CS:MC system evidencedthe amorphous character of the electrolyte samples. The morphology of the samples in FESEM images supported the amorphous behavior of the solid electrolyte films. The results of impedance and Bode plotindicate that the bulk resistance decreasedwith increasing salt concentration. The highest DC conductivity was found to be 2.81 × 10-3 S/cm. The electrical equivalent circuit (EEC) model was conducted for selected samples to explain the complete picture of the electrical properties.The performance of EDLC cells was examined at room temperature by electrochemical techniques, such as impedance spectroscopy, cyclic voltammetry (CV) and constant current charge-discharge techniques. It was found that the studied samples exhibit a very good performance as electrolyte for EDLC applications. Ions were found to be the dominant charge carriers in the polymer electrolyte. The ion transference number (tion) was found to be 0.84 while 0.16 for electron transference number (tel). Through investigation of linear sweep voltammetry (LSV), the CS:MC:NH4SCN system was found to be electrochemically stable up to 1.8 V. The CV plot revealed no redox peak, indicating the occurrence of charge double-layer at the surface of activated carbon electrodes. Specific capacitance (Cspe) for the fabricated EDLC was calculated using CV plot and charge-discharge analyses. It was found to be 66.3 F g-1 and 69.9 F g-1 (at thefirst cycle), respectively. Equivalent series resistance (Resr) of the EDLC was also identified, ranging from 50.0 to 150.0 Ω. Finally, energy density (Ed) was stabilized to anaverage of 8.63 Wh kg-1 from the 10th cycle to the 100th cycle. The first cycle obtained power density (Pd) of 1666.6 W kg-1 and then itdropped to 747.0 W kg-1 at the 50th cycle and continued to drop to 555.5 W kg-1 as the EDLC completed 100 cycles.
    Matched MeSH terms: Polymers/chemistry*
  17. Fulltext Structural, Impedance, and EDLC Characteristics of Proton Conducting Chitosan-Based Polymer Blend Electrolytes with High Electrochemical Stability
    Aziz SB, Abdulwahid RT, Hamsan MH, Brza MA, Abdullah RM, Kadir MFZ, et al.
    Molecules, 2019 Sep 27;24(19).
    PMID: 31569650 DOI: 10.3390/molecules24193508
    In this report, a facile solution casting technique was used to fabricate polymer blend electrolytes of chitosan (CS):poly (ethylene oxide) (PEO):NH4SCN with high electrochemical stability (2.43V). Fourier transform infrared (FTIR) spectroscopy was used to investigate the polymer electrolyte formation. For the electrochemical property analysis, cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) techniques were carried out. Referring to the FTIR spectra, a complex formation between the added salt and CS:PEO was deduced by considering the decreasing and shifting of FTIR bands intensity in terms of functional groups. The CS:PEO:NH4SCN electrolyte was found to be electrochemically stable as the applied voltage linearly swept up to 2.43V. The cyclic voltammogram has presented a wide potential window without showing any sign of redox peaks on the electrode surface. The proved mechanisms of charge storage in these fabricated systems were found to be double layer charging. The EIS analysis showed the existence of bulk resistance, wherein the semicircle diameter decreased with increasing salt concentration. The calculated maximum DC conductivity value was observed to be 2.11 × 10-4 S/cm for CS:PEO incorporated with 40 wt% of NH4SCN salt. The charged species in CS:PEO:NH4SCN electrolytes were considered to be predominantly ionic in nature. This was verified from transference number analysis (TNM), in which ion and electron transference numbers were found to be tion = 0.954 and tel = 0.045, respectively. The results obtained for both ion transference number and DC conductivity implied the possibility of fabricating electrolytes for electrochemical double layer capacitor (EDLC) device application. The specific capacitance of the fabricated EDLC was obtained from the area under the curve of the CV plot.
    Matched MeSH terms: Polymers/chemistry*
  18. Hemodialysis performance and anticoagulant activities of PVP-k25 and carboxylic-multiwall nanotube composite blended Polyethersulfone membrane
    Irfan M, Irfan M, Shah SM, Baig N, Saleh TA, Ahmed M, et al.
    Mater Sci Eng C Mater Biol Appl, 2019 Oct;103:109769.
    PMID: 31349444 DOI: 10.1016/j.msec.2019.109769
    Non-covalent electrostatic interaction between amide nitrogen and carbonyl carbon of shorter chain length of polyvinylpyrrolidone (PVP-k25) was developed with in-house carboxylic oxidized multiwall carbon nanotubes (O-MWCNT) and then blended with Polyethersulfone (PES) polymer. FTIR analysis was utilized to confirm bonding nature of nano-composites (NCs) of O-MWCNT/PVP-k25 and casting membranes. Non-solvent induces phase separation process developed regular finger-like channels in composite membranes whereas pristine PES exhibited spongy entities as studied by cross sectional analysis report of FESEM. Further, FESEM instrument was also utilized to observe the dispersion of O-MWCNT/PVP based nanocomposite (NCs) with PES and membranes leaching phenomena analysis. Contact angle experiments described 24% improvement of hydrophilic behaviour, leaching ratio of additives was reduced to 1.89%, whereas water flux enhanced up to 6 times. Bovine serum albumin (BSA) and lysozyme based antifouling analysis shown up to 25% improvement, whereas 84% of water flux was regained after protein fouling than pristine PES. Anticoagulant activity was reported by estimating prothrombin, thrombin, plasma re-calcification times and production of fibrinogen cluster with platelets-adhesions photographs and hemolysis experiments. Composite membranes exhibited 3.4 and 3 times better dialysis clearance ratios of urea and creatinine solutes as compared to the raw PES membrane.
    Matched MeSH terms: Polymers/chemistry*
  19. Fulltext Poly(2,6-Dimethyl-1,4-Phenylene Oxide)-Based Hydroxide Exchange Separator Membranes for Zinc-Air Battery
    Abbasi A, Hosseini S, Somwangthanaroj A, Mohamad AA, Kheawhom S
    Int J Mol Sci, 2019 Jul 26;20(15).
    PMID: 31357565 DOI: 10.3390/ijms20153678
    Rechargeable zinc-air batteries are deemed as the most feasible alternative to replace lithium-ion batteries in various applications. Among battery components, separators play a crucial role in the commercial realization of rechargeable zinc-air batteries, especially from the viewpoint of preventing zincate (Zn(OH)42-) ion crossover from the zinc anode to the air cathode. In this study, a new hydroxide exchange membrane for zinc-air batteries was synthesized using poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) as the base polymer. PPO was quaternized using three tertiary amines, including trimethylamine (TMA), 1-methylpyrolidine (MPY), and 1-methylimidazole (MIM), and casted into separator films. The successful synthesis process was confirmed by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, while their thermal stability was examined using thermogravimetric analysis. Besides, their water/electrolyte absorption capacity and dimensional change, induced by the electrolyte uptake, were studied. Ionic conductivity of PPO-TMA, PPO-MPY, and PPO-MIM was determined using electrochemical impedance spectroscopy to be 0.17, 0.16, and 0.003 mS/cm, respectively. Zincate crossover evaluation tests revealed very low zincate diffusion coefficient of 1.13 × 10-8, and 0.28 × 10-8 cm2/min for PPO-TMA, and PPO-MPY, respectively. Moreover, galvanostatic discharge performance of the primary batteries assembled using PPO-TMA and PPO-MPY as initial battery tests showed a high specific discharge capacity and specific power of ~800 mAh/gZn and 1000 mWh/gZn, respectively. Low zincate crossover and high discharge capacity of these separator membranes makes them potential materials to be used in zinc-air batteries.
    Matched MeSH terms: Polymers/chemistry*
  20. Fulltext Engineering of Naproxen Loaded Polymer Hybrid Enteric Microspheres for Modified Release Tablets: Development, Characterization, in silico Modelling and in vivo Evaluation
    Hameed HA, Khan S, Shahid M, Ullah R, Bari A, Ali SS, et al.
    Drug Des Devel Ther, 2020;14:27-41.
    PMID: 32021089 DOI: 10.2147/DDDT.S232111
    BACKGROUND: Naproxen (NP) is a non-steroidal anti-inflammatory drug with poor aqueous solubility and low oral bioavailability, which may lead to therapeutic failure. NP causes crucial GIT irritation, bleeding, and peptic and duodenal ulcers.

    PURPOSE OF THE STUDY: This study aimed to engineer and characterize polymer hybrid enteric microspheres using an integrated (experimental and molecular modelling) approach with further development to solid dosage form with modified drug release kinetics and improved bioavailability.

    MATERIALS AND METHODS: NP loaded polymer hybrid enteric microspheres (PHE-Ms) were fabricated by using a modified solvent evaporation technique coupled with molecular modelling (MM) approach. The PHE-Ms were characterized by particle size, distribution, morphology, crystallinity, EE, drug-polymer compatibility, and DSC. The optimized NP loaded PHE-Ms were further subjected to downstream procedures including tablet dosage form development, stability studies and comparative in vitro-in vivo evaluation.

    RESULTS: The hydrophobic polymer EUD-L100 and hydrophilic polymer HPMC-E5 delayed and modified drug release at intestinal pH while imparting retardation of NP release at gastric pH to diminish the gastric side effects. The crystallinity of the NP loaded PHE-Ms was established through DSC and P (XRD). The particle size for the developed formulations of PEH-Ms (M1-M5) was in the range from 29.06 ±7.3-74.31 ± 17.7 μm with Span index values of 0.491-0.69, respectively. The produced NP hybrid microspheres demonstrated retarded drug release at pH 1.2 and improved dissolution at pH 6.8. The in vitro drug release patterns were fitted to various release kinetic models and the best-followed model was the Higuchi model with a release exponent "n" value > 0.5. Stability studies at different storage conditions confirmed stability of the NP loaded PHE-Ms based tablets (P<0.05). The molecular modelling (MM) study resulted in adequate binding energy of co-polymer complex SLS-Eudragit-HPMC-Naproxen (-3.9 kcal/mol). In contrast to the NP (unprocessed) and marketed formulations, a significant increase in the Cmax of PHE-MT1 (44.41±4.43) was observed.

    CONCLUSION: The current study concludes that developing NP loaded PHE-Ms based tablets could effectively reduce GIT consequences with restored therapeutic effects. The modified release pattern could improve the dissolution rate and enhancement of oral bioavailability. The MM study strengthens the polymer-drug relationship in microspheres.

    Matched MeSH terms: Polymers/chemistry*
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