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Search Results (16)

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Keywords = polycarbonate (PC) membrane

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13 pages, 8091 KiB  
Article
Polycarbonate Nanofiber Filters with Enhanced Efficiency and Antibacterial Performance
by Miren Blanco, Cristina Monteserín, Estíbaliz Gómez, Estíbaliz Aranzabe, Jose Luis Vilas Vilela, Ana Pérez-Márquez, Jon Maudes, Celina Vaquero, Nieves Murillo, Iñaki Zalakain and Leire Ruiz Rubio
Polymers 2025, 17(4), 444; https://doi.org/10.3390/polym17040444 - 8 Feb 2025
Viewed by 1037
Abstract
The need for clean and safe air quality is a global priority that extends to diverse environments, including households, industrial spaces, and areas requiring respiratory personal protection. In this study, polycarbonate (PC) nanofiber filters coated with a coating containing a silver salt were [...] Read more.
The need for clean and safe air quality is a global priority that extends to diverse environments, including households, industrial spaces, and areas requiring respiratory personal protection. In this study, polycarbonate (PC) nanofiber filters coated with a coating containing a silver salt were prepared by the electrospinning process and a subsequent dipping–extraction method. These nanofiber filters presented the enhancement of air filtration efficiency and reinforcement of antibacterial properties. The research includes diverse PC filter structures, assessing beaded and non-beaded structures and varying areal weights. The study evaluated filtration efficiency across NaCl particle sizes (50–400 nm) and pressure drop outcomes. In addition, the antibacterial activity of the coated filters against E. coli and other coliforms was investigated by the filtration membrane method. Repetitive testing consistently yields high efficiencies, reaching 100% in thicker filters, and minimal air resistance in beaded filters, presenting an advantage over the current systems. Furthermore, the new properties of the filters will enhance environmental safety, and their time of use will be increased since they prevented the growth of bacteria, and no significant colonies were seen. Considering all these factors, these filters presented promising application in environments with harmful microorganisms, for the development of advanced industrial filtering systems or even hygienic masks. Full article
(This article belongs to the Section Polymer Fibers)
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14 pages, 6733 KiB  
Article
The Effects of the Coating and Aging of Biodegradable Polylactic Acid Membranes on In Vitro Primary Human Retinal Pigment Epithelium Cells
by Georgina Faura, Hana Studenovska, David Sekac, Zdenka Ellederova, Goran Petrovski and Lars Eide
Biomedicines 2024, 12(5), 966; https://doi.org/10.3390/biomedicines12050966 - 26 Apr 2024
Cited by 2 | Viewed by 2005
Abstract
Age-related macular degeneration (AMD) is the most frequent cause of blindness in developed countries. The replacement of dysfunctional human retinal pigment epithelium (hRPE) cells by the transplantation of in vitro-cultivated hRPE cells to the affected area emerges as a feasible strategy for regenerative [...] Read more.
Age-related macular degeneration (AMD) is the most frequent cause of blindness in developed countries. The replacement of dysfunctional human retinal pigment epithelium (hRPE) cells by the transplantation of in vitro-cultivated hRPE cells to the affected area emerges as a feasible strategy for regenerative therapy. Synthetic biomimetic membranes arise as powerful hRPE cell carriers, but as biodegradability is a requirement, it also poses a challenge due to its limited durability. hRPE cells exhibit several characteristics that putatively respond to the type of membrane carrier, and they can be used as biomarkers to evaluate and further optimize such membranes. Here, we analyze the pigmentation, transepithelial resistance, genome integrity, and maturation markers of hRPE cells plated on commercial polycarbonate (PC) versus in-house electrospun polylactide-based (PLA) membranes, both enabling separate apical/basolateral compartments. Our results show that PLA is superior to PC-based membranes for the cultivation of hRPEs, and the BEST1/RPE65 maturation markers emerge as the best biomarkers for addressing the quality of hRPE cultivated in vitro. The stability of the cultures was observed to be affected by PLA aging, which is an effect that could be partially palliated by the coating of the PLA membranes. Full article
(This article belongs to the Topic Advanced Functional Materials for Regenerative Medicine)
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9 pages, 1601 KiB  
Article
Bisphenol A and Bisphenol S in Hemodialyzers
by Zahin Haq, Xin Wang, Qiuqiong Cheng, Gabriela F. Dias, Christoph Moore, Dorothea Piecha, Peter Kotanko, Chih-Hu Ho and Nadja Grobe
Toxins 2023, 15(7), 465; https://doi.org/10.3390/toxins15070465 - 20 Jul 2023
Cited by 5 | Viewed by 3084
Abstract
Bisphenol A (BPA)-based materials are used in the manufacturing of hemodialyzers, including their polycarbonate (PC) housings and polysulfone (PS) membranes. As concerns for BPA’s adverse health effects rise, the regulation on BPA exposure is becoming more rigorous. Therefore, BPA alternatives, such as Bisphenol [...] Read more.
Bisphenol A (BPA)-based materials are used in the manufacturing of hemodialyzers, including their polycarbonate (PC) housings and polysulfone (PS) membranes. As concerns for BPA’s adverse health effects rise, the regulation on BPA exposure is becoming more rigorous. Therefore, BPA alternatives, such as Bisphenol S (BPS), are increasingly used. It is important to understand the patient risk of BPA and BPS exposure through dialyzer use during hemodialysis. Here, we report the bisphenol levels in extractables and leachables obtained from eight dialyzers currently on the market, including high-flux and medium cut-off membranes. A targeted liquid chromatography–mass spectrometry strategy utilizing stable isotope-labeled internal standards provided reliable data for quantitation with the standard addition method. BPA ranging from 0.43 to 32.82 µg/device and BPS ranging from 0.02 to 2.51 µg/device were detected in dialyzers made with BPA- and BPS-containing materials, except for the novel FX CorAL 120 dialyzer. BPA and BPS were also not detected in bloodline controls and cellulose-based membranes. Based on the currently established tolerable intake (6 µg/kg/day), the resulting margin of safety indicates that adverse effects are unlikely to occur in hemodialysis patients exposed to BPA and BPS quantified herein. With increasing availability of new data and information about the toxicity of BPA and BPS, the patient safety limits of BPA and BPS in those dialyzers may need a re-evaluation in the future. Full article
(This article belongs to the Section Uremic Toxins)
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21 pages, 11512 KiB  
Article
Isolation and Staining Reveal the Presence of Extracellular DNA in Marine Gel Particles
by Aisha S. M. Al-Wahaibi, Robert C. Upstill-Goddard and J. Grant Burgess
Gels 2023, 9(3), 251; https://doi.org/10.3390/gels9030251 - 21 Mar 2023
Cited by 1 | Viewed by 2932
Abstract
Marine gel particles (MGP) are amorphous hydrogel exudates from bacteria and microalgae that are ubiquitous in the oceans, but their biochemical composition and function are poorly understood. While dynamic ecological interactions between marine microorganisms and MGPs may result in the secretion and mixing [...] Read more.
Marine gel particles (MGP) are amorphous hydrogel exudates from bacteria and microalgae that are ubiquitous in the oceans, but their biochemical composition and function are poorly understood. While dynamic ecological interactions between marine microorganisms and MGPs may result in the secretion and mixing of bacterial extracellular polymeric substances (EPS) such as nucleic acids, compositional studies currently are limited to the identification of acidic polysaccharides and proteins in transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP). Previous studies targeted MGPs isolated by filtration. We developed a new way of isolating MGPs from seawater in liquid suspension and applied it to identify extracellular DNA (eDNA) in North Sea surface seawater. Seawater was filtered onto polycarbonate (PC) filters with gentle vacuum filtration, and then the filtered particles were gently resuspended in a smaller volume of sterile seawater. The resulting MGPs ranged in size from 0.4 to 100 µm in diameter. eDNA was detected by fluorescent microscopy using YOYO-1 (for eDNA), with Nile red (targeting cell membranes) as a counterstain. TOTO-3 was also used to stain eDNA, with ConA to localise glycoproteins and SYTO-9 for the live/dead staining of cells. Confocal laser scanning microscopy (CLSM) revealed the presence of proteins and polysaccharides. We found eDNA to be universally associated with MGPs. To further elucidate the role of eDNA, we established a model experimental MGP system using bacterial EPS from Pseudoalteromonas atlantica that also contained eDNA. Our results clearly demonstrate the occurrence of eDNA in MGPs, and should aid furthering our understanding of the micro-scale dynamics and fate of MGPs that underly the large-scale processes of carbon cycling and sedimentation in the ocean. Full article
(This article belongs to the Section Gel Analysis and Characterization)
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18 pages, 8014 KiB  
Article
MetaMembranes for the Sensitivity Enhancement of Wearable Piezoelectric MetaSensors
by Saman Farhangdoust, Gary Georgeson and Jeong-Beom Ihn
Sensors 2022, 22(5), 1909; https://doi.org/10.3390/s22051909 - 1 Mar 2022
Cited by 7 | Viewed by 2886
Abstract
The low stretchability of plain membranes restricts the sensitivity of conventional diaphragm-based pressure and inflatable piezoelectric sensors. Using theoretical and computational tools, we characterized current limitations and explored metamaterial-inspired membranes (MetaMems) to resolve these issues. This paper develops two MetaMem pressure sensors (MPSs) [...] Read more.
The low stretchability of plain membranes restricts the sensitivity of conventional diaphragm-based pressure and inflatable piezoelectric sensors. Using theoretical and computational tools, we characterized current limitations and explored metamaterial-inspired membranes (MetaMems) to resolve these issues. This paper develops two MetaMem pressure sensors (MPSs) to enrich the sensitivity and stretchability of the conventional sensors. Two auxetic hexagonal and kirigami honeycombs are proposed to create a negative Poisson’s ratio (NPR) in the MetaMems which enables them to expand the piezo-element of sensors in both longitudinal and transverse directions much better, and consequently provides the MPSs’ diaphragm a higher capability for flexural deformation. Polyvinylidene fluoride (PVDF) and polycarbonate (PC) are considered as the preferable materials for the piezo-element and MetaMem, respectively. A finite element analysis was conducted to investigate the stretchability behavior of the MetaMems and study its effect on the PVDF’s polarization and sensor sensitivity. The results obtained from theoretical analysis and numerical simulations demonstrate that the proposed MetaMems enhance the sensitivity of pressure sensors up to 3.8 times more than an equivalent conventional sensor with a plain membrane. This paper introduces a new class of flexible MetaMems to advance wearable piezoelectric metasensor technologies. Full article
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28 pages, 3178 KiB  
Review
Recent Progress in the Membrane Distillation and Impact of Track-Etched Membranes
by Arman B. Yeszhanov, Ilya V. Korolkov, Saule S. Dosmagambetova, Maxim V. Zdorovets and Olgun Güven
Polymers 2021, 13(15), 2520; https://doi.org/10.3390/polym13152520 - 30 Jul 2021
Cited by 37 | Viewed by 4721
Abstract
Membrane distillation (MD) is a rapidly developing field of research and finds applications in desalination of water, purification from nonvolatile substances, and concentration of various solutions. This review presents data from recent studies on the MD process, MD configuration, the type of membranes [...] Read more.
Membrane distillation (MD) is a rapidly developing field of research and finds applications in desalination of water, purification from nonvolatile substances, and concentration of various solutions. This review presents data from recent studies on the MD process, MD configuration, the type of membranes and membrane hydrophobization. Particular importance has been placed on the methods of hydrophobization and the use of track-etched membranes (TeMs) in the MD process. Hydrophobic TeMs based on poly(ethylene terephthalate) (PET), poly(vinylidene fluoride) (PVDF) and polycarbonate (PC) have been applied in the purification of water from salts and pesticides, as well as in the concentration of low-level liquid radioactive waste (LLLRW). Such membranes are characterized by a narrow pore size distribution, precise values of the number of pores per unit area and narrow thickness. These properties of membranes allow them to be used for more accurate water purification and as model membranes used to test theoretical models (for instance LEP prediction). Full article
(This article belongs to the Special Issue Advanced Polymer Membranes)
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21 pages, 7014 KiB  
Article
Optimization of the Transwell® System for Assessing the Dissolution Behavior of Orally Inhaled Drug Products through In Vitro and In Silico Approaches
by Elham Amini, Abhinav Kurumaddali, Sharvari Bhagwat, Simon M. Berger and Günther Hochhaus
Pharmaceutics 2021, 13(8), 1109; https://doi.org/10.3390/pharmaceutics13081109 - 21 Jul 2021
Cited by 9 | Viewed by 3977
Abstract
The aim of this study was to further evaluate and optimize the Transwell® system for assessing the dissolution behavior of orally inhaled drug products (OIDPs), using fluticasone propionate as a model drug. Sample preparation involved the collection of a relevant inhalable dose [...] Read more.
The aim of this study was to further evaluate and optimize the Transwell® system for assessing the dissolution behavior of orally inhaled drug products (OIDPs), using fluticasone propionate as a model drug. Sample preparation involved the collection of a relevant inhalable dose fraction through an anatomical mouth/throat model, resulting in a more uniform presentation of drug particles during the subsequent dissolution test. The method differed from previously published procedures by (1) using a 0.4 µm polycarbonate (PC) membrane, (2) stirring the receptor compartment, and (3) placing the drug-containing side of the filter paper face downwards, towards the PC membrane. A model developed in silico, paired with the results of in vitro studies, suggested that a dissolution medium providing a solubility of about 5 µg/mL would be a good starting point for the method’s development, resulting in mean transfer times that were about 10 times longer than those of a solution. Furthermore, the model suggested that larger donor/receptor and sampling volumes (3, 3.3 and 2 mL, respectively) will significantly reduce the so-called “mass effect”. The outcomes of this study shed further light on the impact of experimental conditions on the complex interplay of dissolution and diffusion within a volume-limited system, under non-sink conditions. Full article
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14 pages, 2595 KiB  
Article
[EMIM][Tf2N]-Modified Silica as Filler in Mixed Matrix Membrane for Carbon Dioxide Separation
by Siti Nur Alwani Shafie, Nik Abdul Hadi Md Nordin, Muhammad Roil Bilad, Nurasyikin Misdan, Norazlianie Sazali, Zulfan Adi Putra, Mohd Dzul Hakim Wirzal, Alamin Idris, Juhana Jaafar and Zakaria Man
Membranes 2021, 11(5), 371; https://doi.org/10.3390/membranes11050371 - 19 May 2021
Cited by 14 | Viewed by 3714
Abstract
This study focuses on the effect of modified silica fillers by [EMIN][Tf2N] via physical adsorption on the CO2 separation performance of a mixed matrix membrane (MMM). The IL-modified silica was successfully synthesized as the presence of fluorine element was observed [...] Read more.
This study focuses on the effect of modified silica fillers by [EMIN][Tf2N] via physical adsorption on the CO2 separation performance of a mixed matrix membrane (MMM). The IL-modified silica was successfully synthesized as the presence of fluorine element was observed in both Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses. The prepared MMMs with different loadings of the IL-modified silica were then compared with an unmodified silica counterpart and neat membrane. The morphology of IL-modified MMMs was observed to have insignificant changes, while polymer chains of were found to be slightly more flexible compared to their counterpart. At 2 bar of operating pressure, a significant increase in performance was observed with the incorporation of 3 wt% Sil-IL fillers compared to that of pure polycarbonate (PC). The permeability increased from 353 to 1151 Barrer while the CO2/CH4 selectivity increased from 20 to 76. The aforementioned increment also exceeded the Robeson upper bound. This indicates that the incorporation of fillers surface-modified with ionic liquid in an organic membrane is worth exploring for CO2 separation. Full article
(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)
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16 pages, 5952 KiB  
Article
Highly Sensitive and Cost-Effective Portable Sensor for Early Gastric Carcinoma Diagnosis
by Saw-Lin Oo, Shishir Venkatesh, Vaithinathan Karthikeyan, Clement Manohar Arava, Spoorthy Pathikonda, Peter K. N. Yu, Terrence C. K. Lau, Xianfeng Chen and Vellaisamy A. L. Roy
Sensors 2021, 21(8), 2639; https://doi.org/10.3390/s21082639 - 9 Apr 2021
Cited by 12 | Viewed by 4387
Abstract
Facile and efficient early detection of cancer is a major challenge in healthcare. Herein we developed a novel sensor made from a polycarbonate (PC) membrane with nanopores, followed by sequence-specific Oligo RNA modification for early gastric carcinoma diagnosis. In this design, the gastric [...] Read more.
Facile and efficient early detection of cancer is a major challenge in healthcare. Herein we developed a novel sensor made from a polycarbonate (PC) membrane with nanopores, followed by sequence-specific Oligo RNA modification for early gastric carcinoma diagnosis. In this design, the gastric cancer antigen CA72-4 is specifically conjugated to the Oligo RNA, thereby inhibiting the electrical current through the PC membrane in a concentration-dependent manner. The device can determine the concentration of cancer antigen CA72-4 in the range from 4 to 14 U/mL, possessing a sensitivity of 7.029 µAU−1mLcm−2 with a linear regression (R2) of 0.965 and a lower detection limit of 4 U/mL. This device has integrated advantages including high specificity and sensitivity and being simple, portable, and cost effective, which collectively enables a giant leap for cancer screening technologies towards clinical use. This is the first report to use RNA aptamers to detect CA72-4 for gastric carcinoma diagnosis. Full article
(This article belongs to the Section Biomedical Sensors)
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16 pages, 5535 KiB  
Article
Surface Enhanced Raman Spectroscopy With Electrodeposited Copper Ultramicro-Wires With/Without Silver Nanostars Decoration
by Margherita Longoni, Maria Sole Zalaffi, Lavinia de Ferri, Angela Maria Stortini, Giulio Pojana and Paolo Ugo
Nanomaterials 2021, 11(2), 518; https://doi.org/10.3390/nano11020518 - 18 Feb 2021
Cited by 10 | Viewed by 4306
Abstract
The electrochemical preparation of arrays of copper ultramicrowires (CuUWs) by using porous membranes as templates is critically revisited, with the goal of obtaining cheap but efficient substrates for surface enhanced Raman spectroscopy (SERS). The role of the materials used for the electrodeposition is [...] Read more.
The electrochemical preparation of arrays of copper ultramicrowires (CuUWs) by using porous membranes as templates is critically revisited, with the goal of obtaining cheap but efficient substrates for surface enhanced Raman spectroscopy (SERS). The role of the materials used for the electrodeposition is examined, comparing membranes of anodized aluminum oxide (AAO) vs. track-etched polycarbonate (PC) as well as copper vs. glassy carbon (GC) as electrode material. A voltammetric study performed on bare electrodes and potentiostatic tests on membrane coated electrodes allowed the optimization of the deposition parameters. The final arrays of CuUWs were obtained by chemical etching of the template, with NaOH for AAO and CH2Cl2 for PC. After total etching of the template, SERS spectra were recorded on CuUWs using benzenethiol as SERS probe with known spectral features. The CuUW substrates displayed good SERS properties, providing enhancement factor in the 103–104 range. Finally, it was demonstrated that higher Raman enhancement can be achieved when CuUWs are decorated with silver nanostars, supporting the formation of SERS active hot-spots at the bimetallic interface. Full article
(This article belongs to the Special Issue Low-Dimensional Nanomaterials for Photonics and Optoelectronics)
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15 pages, 2247 KiB  
Article
Structure and Electronic Properties of InSb Nanowires Grown in Flexible Polycarbonate Membranes
by Abhay Pratap Singh, Kevin Roccapriore, Zaina Algarni, Riyadh Salloom, Teresa D. Golden and U. Philipose
Nanomaterials 2019, 9(9), 1260; https://doi.org/10.3390/nano9091260 - 5 Sep 2019
Cited by 9 | Viewed by 3765
Abstract
A dense array of vertically aligned indium antimonide (InSb) nanowires with high aspect ratio (diameter 150 nm, length 20 μ m) were grown in the pores of a track-etched polycarbonate membrane via a one-step electrochemical method. There are several reports on InSb nanowire [...] Read more.
A dense array of vertically aligned indium antimonide (InSb) nanowires with high aspect ratio (diameter 150 nm, length 20 μ m) were grown in the pores of a track-etched polycarbonate membrane via a one-step electrochemical method. There are several reports on InSb nanowire growth in the pores of a mechanically rigid, nano-channel alumina template (NCA), where nanowire growth occurs in the pores of the NCA. This work on InSb nanowire growth in pores of track-etched polycarbonate (PC) membrane sheds light on the various factors that affect nucleation and nanowire growth. The average length and diameter of the as-grown nanowires was about 10 μ m and 150 nm, respectively. Two possible mechanisms accounting for two different morphologies of the as-grown nanowires are proposed. The polycrystallinity observed in some of the nanowires is explained using the 3D ‘nucleation-coalescence’ mechanism. On the other hand, single crystal nanowires with a high density of twin defects and stacking faults grow epitaxially by a two-dimensional (2D) nucleation/growth mechanism. To assess the electrical quality of the nanowires, two- and four-terminal devices were fabricated using a single InSb nanowire contacted by two Ni electrodes. It was found that, at low bias, the ohmic current is controlled by charge diffusion from the bulk contacts. On the other hand, at high bias, the effects of space charge limited current (SCLC) are evident in the current–voltage behavior, characteristic of transport through structures with reduced electrostatic screening. A cross-over from ohmic to SCLC occurs at about 0.14 V, yielding a free carrier concentration of the order of 10 14 cm 3 . Full article
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18 pages, 7197 KiB  
Article
One-Step Bark-Like Imitated Polypropylene (PP)/Polycarbonate (PC) Nanofibrous Meltblown Membrane for Efficient Particulate Matter Removal
by Ting-Ting Li, Xixi Cen, Hai-Tao Ren, Fei Sun, Qi Lin, Ching-Wen Lou and Jia-Horng Lin
Polymers 2019, 11(8), 1307; https://doi.org/10.3390/polym11081307 - 4 Aug 2019
Cited by 21 | Viewed by 4183
Abstract
A bark-like imitated polypr opylene (PP)/polycarbonate (PC) nanofibrous membrane was constructed by one-step meltblown technique for efficient particulate matter (PM) removal. The effects of PC content (0%, 1%, 3%, 5%, and 7%) on membrane thermal stability, microscopic characteristics, filtration performance, hydrophilicity, and water [...] Read more.
A bark-like imitated polypr opylene (PP)/polycarbonate (PC) nanofibrous membrane was constructed by one-step meltblown technique for efficient particulate matter (PM) removal. The effects of PC content (0%, 1%, 3%, 5%, and 7%) on membrane thermal stability, microscopic characteristics, filtration performance, hydrophilicity, and water vapor transmission were investigated. The results demonstrated that using facile design of incompatibility and viscosity difference between PC and PP polymers decreases average fiber diameter, creating a bark-like groove appearance and increasing surface potential, making a new PP/PC membrane with high filtration performance. The resultant PP/PC membrane had finer average fiber diameter of 0.63 μm, which was nearly 89.41% lower than PP membranes (5.95 μm), and its quality factor (0.036 Pa−1) was nearly 2.12 times than that of PP membranes (0.017 Pa−1) with the die hole diameter of 0.5 mm. This fabrication technique of a special meltblown filter membrane saves the cost of die retrofitting and post-processing, which provides an innovative method for particulate efficient removal of high efficient filters. Full article
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10 pages, 3042 KiB  
Article
Improving Oxygen Permeability and Thermostability of Polycarbonate via Copolymerization Modification with Bio-Phenol Polysiloxane
by Xiaoyan Pang, Xin Ge, Jianye Ji, Weijie Liang, Ruoling Liu, Xunjun Chen, Guoqiang Yin and Jianfang Ge
Polymers 2019, 11(8), 1302; https://doi.org/10.3390/polym11081302 - 3 Aug 2019
Cited by 11 | Viewed by 5110
Abstract
As a new kind of functionalized polysiloxane with chemical reactivity, bio-phenol polysiloxane was synthesized through facile heterogeneous catalytic route. Bio-phenol polysiloxane/polycarbonate (Si/PC) block copolymer was synthesized via a three-step approach, and the effect of the amount of bio-phenol polysiloxane on the properties of [...] Read more.
As a new kind of functionalized polysiloxane with chemical reactivity, bio-phenol polysiloxane was synthesized through facile heterogeneous catalytic route. Bio-phenol polysiloxane/polycarbonate (Si/PC) block copolymer was synthesized via a three-step approach, and the effect of the amount of bio-phenol polysiloxane on the properties of Si/PC copolymer was then studied. The structure and morphology of Si/PC copolymer were characterized, showing that, when the amount of bio-phenol polysiloxane reached 20%, the pyrolysis temperature of Si/PC copolymer at 5% weight loss was 450.8 °C which was 76.1 °C higher than pure PC. The oxygen permeability of 20%Si/PC copolymer membrane was 502.65 cm3/m2·24h·0.1MPa, which was increased by 128.4% compared with pure PC membrane. The mechanical property and hydrophobicity of Si/PC copolymer had been improved. Full article
(This article belongs to the Collection Silicon-Containing Polymeric Materials)
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12 pages, 4772 KiB  
Article
Plasma Activation of Copper Nanowires Arrays for Electrocatalytic Sensing of Nitrate in Food and Water
by Angela Maria Stortini, Sabrina Fabris, Gloria Saorin, Emanuele Verga Falzacappa, Ligia Maria Moretto and Paolo Ugo
Nanomaterials 2019, 9(2), 150; https://doi.org/10.3390/nano9020150 - 25 Jan 2019
Cited by 14 | Viewed by 3956
Abstract
Electrochemical methods for nitrate detection are very attractive since they are suitable for in-field and decentralized monitoring. Copper electrodes are often used to this aim as this metal presents interesting electrocatalytic properties towards nitrate reduction. In this research, we study improvements in the [...] Read more.
Electrochemical methods for nitrate detection are very attractive since they are suitable for in-field and decentralized monitoring. Copper electrodes are often used to this aim as this metal presents interesting electrocatalytic properties towards nitrate reduction. In this research, we study improvements in the electrochemical analysis of nitrate in natural water and food by taking advantage of the detection capabilities of ensembles of copper nanowire electrodes (CuWNEEs). These electrodes are prepared via template electrodeposition of copper within the nanopores of track-etched polycarbonate (PC) membranes. A critical step in the preparation of these sensors is the removal of the template. Here, we applied the combination of chemical etching with atmospheric plasma cleaning which proved suitable for improving the performance of the nanostructured copper electrode. Analytical results obtained with the CuWNEE sensor for nitrate analyses in river water samples compare satisfactorily with those achieved by standard chromatographic or spectroscopic methods. Experimental results concerning the application of the CuWNEEs for nitrate analysis in food samples are also presented and discussed, with focus on nitrate detection in leafy vegetables. Full article
(This article belongs to the Special Issue Nanomaterials for Electrocatalytic Applications in Energy and Sensing)
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18 pages, 5209 KiB  
Article
Effects of Phase Separation Behavior on Morphology and Performance of Polycarbonate Membranes
by Alamin Idris, Zakaria Man, Abdulhalim S. Maulud and Muhammad Saad Khan
Membranes 2017, 7(2), 21; https://doi.org/10.3390/membranes7020021 - 5 Apr 2017
Cited by 71 | Viewed by 11649
Abstract
The phase separation behavior of bisphenol-A-polycarbonate (PC), dissolved in N-methyl-2-pyrrolidone and dichloromethane solvents in coagulant water, was studied by the cloud point method. The respective cloud point data were determined by titration against water at room temperature and the characteristic binodal curves [...] Read more.
The phase separation behavior of bisphenol-A-polycarbonate (PC), dissolved in N-methyl-2-pyrrolidone and dichloromethane solvents in coagulant water, was studied by the cloud point method. The respective cloud point data were determined by titration against water at room temperature and the characteristic binodal curves for the ternary systems were plotted. Further, the physical properties such as viscosity, refractive index, and density of the solution were measured. The critical polymer concentrations were determined from the viscosity measurements. PC/NMP and PC/DCM membranes were fabricated by the dry-wet phase inversion technique and characterized for their morphology, structure, and thermal stability using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis, respectively. The membranes’ performances were tested for their permeance to CO2, CH4, and N2 gases at 24 ± 0.5 °C with varying feed pressures from 2 to 10 bar. The PC/DCM membranes appeared to be asymmetric dense membrane types with appreciable thermal stability, whereas the PC/NMP membranes were observed to be asymmetric with porous structures exhibiting 4.18% and 9.17% decrease in the initial and maximum degradation temperatures, respectively. The ideal CO2/N2 and CO2/CH4 selectivities of the PC/NMP membrane decreased with the increase in feed pressures, while for the PC/DCM membrane, the average ideal CO2/N2 and CO2/CH4 selectivities were found to be 25.1 ± 0.8 and 21.1 ± 0.6, respectively. Therefore, the PC/DCM membranes with dense morphologies are appropriate for gas separation applications. Full article
(This article belongs to the Section Membrane Physics and Theory)
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