Polymeric Thin Films and Membranes

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Applications".

Deadline for manuscript submissions: closed (25 January 2020) | Viewed by 46050

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Departamento de Termodinámica Aplicada, E.T.S.I.I., Instituto de Tecnología Eléctrica, Universitat Politècnica de València, 46022 València,Spain
Interests: molecular mobility; thermal; mechanical; dielectric properties; biomaterials; nano technology

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Instituto Universitario de Automática e Informática Industrial, Universitat Poltecnica de Valencia, Valencia, Spain
Interests: molecular mobility; thermal; mechanical; dielectric properties; biomaterials; nano technology
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Athlone Institute of Technology, Dublin Road, Athlone, County Westmeath, Ireland
Interests: biomaterials; smart hydrogels; nanotechnology; drug delivery
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Investigations involving polymer films and membranes represent a rapidly growing research area in physics, materials/polymer science, chemistry and engineering. The study of the dynamics of polymer molecules has been one of the most fruitful areas of polymer physics. The glass transition, the precursor of which is the glass-liquid relaxation, is one of the most important unsolved subjects in the physics of condensed matter. In cooling, supercooled liquids can reach a temperature in the vicinity of which ergodicity is lost. The physical properties of the materials are directly related to the structure and molecular mobility of the same. For this reason, a special focus has always been placed on understanding dynamics and the glass transition in polymer films.

In recent years, the current trend to the miniaturization of existing devices has stimulated the development of polymer material thin films, which has brought with it the investment of a substantial effort to understand the dynamics and the glass transition in thin polymer films. The current experimental data supports the idea that the dynamics of thin polymer films is different from bulk. This is due to the fact that confinement effects, as well as interfacial interactions, have a growing impact on film physical properties. Thus, polymers in thin films and nanocomposite structures can exhibit unusual physical properties due to these geometric constraints imposed by the presence of surfaces and interfaces. The mobility change control induced in the vicinity of surfaces and interfaces has important technological implications. Indeed nano-structures are driving many applications in biomedical interactions with polymer films. 

For this reason, significant effort has been invested in the design of new thin polymer materials, as well as in the study of their physical properties in the proximty of surfaces and interfaces, since these interactions have significant implications for both behavior and applications. Furthermore, the interest in polymer surfaces and ultrathin films arises from the development of nanofabrication processes, where knowledge of the structure and dynamics of interfacial layers has significant implications.

This Special Issue, “Polymeric Thin Films and Membranes”, aims to be a collection of high-calibre original/review papers focusing on recent progress on polymeric thin film-based materials. These thin polymer films have numerous technological applications in various industrial and biomedical sectors. Among these applications, we include sensor technologies, microelectronics and optoelectronics, catalysts, electroactive protective shields, bright fluorescent coatings to new adhesives, low friction coatings, the design of energy-efficient materials, new portable devices, such as wearable medical devices, applications as biomaterials and the biocompatibility of medical implants. High temperature polymeric materials for electrical insulation and energy storage are needed for transformational power applications such as pulsed-power and hybrid electrical vehicles.

In addition, the aim is to achieve functional materials using approaches that are simple to realize, using low-cost materials that are potentially scalable. The environmental friendliness at reduced cost represents the driving force for profound changes in contemporary technology. In this respect, new synthetic procedures have been developed using resources of natural origin for the preparation of these new polymeric materials and green chemistry.

Prof. M.J. Sanchis
Dr. Marta Carsí
Dr. Michael J.D. Nugent
Guest Editors

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Keywords

  • dynamic mobility
  • biotechnology
  • biosensors
  • energy-efficient materials
  • polymer coatings
  • nanotechnology
  • smart hydrogels

Published Papers (13 papers)

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Research

9 pages, 2615 KiB  
Article
Preparation and Characterization of PEBAX-5513/AgBF4/BMIMBF4 Membranes for Olefin/Paraffin Separation
by So Young Kim, Younghyun Cho and Sang Wook Kang
Polymers 2020, 12(7), 1550; https://doi.org/10.3390/polym12071550 - 13 Jul 2020
Cited by 8 | Viewed by 2456
Abstract
In this study, we investigated a poly(ether-block-amide)-5513 (PEBAX-5513)/AgBF4/1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) composite membrane, which is expected to have a high stabilizing effect on the Ag+ ions functioning as olefin carriers in the amide group. Poly(ethylene oxide) (PEO) only consists [...] Read more.
In this study, we investigated a poly(ether-block-amide)-5513 (PEBAX-5513)/AgBF4/1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) composite membrane, which is expected to have a high stabilizing effect on the Ag+ ions functioning as olefin carriers in the amide group. Poly(ethylene oxide) (PEO) only consists of ether regions, whereas the PEBAX-5513 copolymer contains both ether and amide regions. However, given the brittle nature of the amide, the penetration of BMIMBF4 remains challenging. The nanoparticles did not stabilize after their formation in the long-term test, thereby resulting in a poor performance compared to previous experiments using PEO as the polymer (selectivity 3; permeance 12.3 GPU). The properties of the functional groups in the polymers were assessed using Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis, which confirmed that the properties endowed during the production of the film using the ionic liquid can impact the performance. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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10 pages, 1668 KiB  
Article
Unveiling the Uniqueness of Crystal Structure and Crystalline Phase Behavior of Anhydrous Octyl β-D-Glucoside Using Aligned Assembly on a Surface
by Shigesaburo Ogawa and Isao Takahashi
Polymers 2020, 12(3), 671; https://doi.org/10.3390/polym12030671 - 17 Mar 2020
Cited by 4 | Viewed by 2300
Abstract
Although the anomalous low crystallinity of octyl β-D-glucoside (β-OGlu) was first proposed more than 30 years ago, many fundamental aspects of its crystal structure and of the crystalline phase behavior of the pure substance have remained uncertain. In this paper, [...] Read more.
Although the anomalous low crystallinity of octyl β-D-glucoside (β-OGlu) was first proposed more than 30 years ago, many fundamental aspects of its crystal structure and of the crystalline phase behavior of the pure substance have remained uncertain. In this paper, we employ grazing-incidence wide-angle X-ray-diffraction measurements using a two-dimensional detector (2D-GI-WAXD) and perpendicularly aligned crystalline films to demonstrate that β-OGlu forms crystal structures consisting of an intermediate phase—like a ripple phase with two large crystal-lattice constants, a and c, comparable to the lengths of its bilayer structures. Furthermore, solid-to-solid phase transitions accompanied by latent heat confirm the existence of a solid-solution-like phase consisting of a crystalline and a liquid-crystal (LC) phase, which persists over a 20 °C temperature range, in a single-component system. In addition, the system forms a superlattice, accompanied by a change in packing of the component sugars in the partial-melting state; this shift is different from the gel-crystal transition observed for a typical lipid system. These facts indicate that even in the crystalline phase formed from a single component, each individual β-OGlu molecule in a single-component phase plays a versatile role in the crystallisation and melting processes. These findings must somewhat explain the specific co-assembling features with proteins of β-OGlu, which has long been used empirically in biochemistry. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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13 pages, 1389 KiB  
Article
Determination of Volatile Water Pollutants Using Cross-Linked Polymeric Ionic Liquid as Solid Phase Micro-Extraction Coatings
by Yuan Tian, Xilan Feng, Yuping Zhang, Quan Yu, Xiaohao Wang and Mengkui Tian
Polymers 2020, 12(2), 292; https://doi.org/10.3390/polym12020292 - 2 Feb 2020
Cited by 11 | Viewed by 2882
Abstract
Ionic liquids found a wide application in catalysis and extraction due to their unique properties. Herein, ethylene glycol dimethacrylate as the cross-linker and 1-vinyl-3- butylimidazolium tetrafluoroborate as functional monomer via thermally initiated free-radical polymerization was prepared as a novel copolymer solid phase micro-extraction [...] Read more.
Ionic liquids found a wide application in catalysis and extraction due to their unique properties. Herein, ethylene glycol dimethacrylate as the cross-linker and 1-vinyl-3- butylimidazolium tetrafluoroborate as functional monomer via thermally initiated free-radical polymerization was prepared as a novel copolymer solid phase micro-extraction (SPME) coating. A surface modified stainless-steel wire was implemented as the substrate. Factors affecting the extraction performances of the copolymer, including the molar ratio of monomers to cross-linkers, the amount of porogen agent, and polymerization time were evaluated and optimized. To evaluate the extraction performance, five commonly seen polycyclic aromatic hydrocarbons (PAHs) were taken as the analytical targets. The potential factors affecting extraction efficiency were optimized. The as-prepared SPME device, coupled with gas chromatography, was successfully applied for the determination of PAHs in water samples. The wide linear range, low detection limit, good reproducibility, selectivity, and excellent thermal stability indicate the promising application of the newly developed SPME fiber in environmental monitoring as well as in other samples having complex matrices. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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14 pages, 2659 KiB  
Article
Development and Properties of Fish Gelatin/Oxidized Starch Double Network Film Catalyzed by Thermal Treatment and Schiff’ Base Reaction
by Yuhao Dong, Hao Chen, Peng Qiao and Zijing Liu
Polymers 2019, 11(12), 2065; https://doi.org/10.3390/polym11122065 - 11 Dec 2019
Cited by 18 | Viewed by 3805
Abstract
In order to improve the properties of fish gelatin (FG), oxidized starch (OS) was adopted to form hetero-covalent linkage with it based on thermal treatment and the Schiff’ base reaction. The effects of different ratios of FG/OS (ranging from 10:1 to 2:1) on [...] Read more.
In order to improve the properties of fish gelatin (FG), oxidized starch (OS) was adopted to form hetero-covalent linkage with it based on thermal treatment and the Schiff’ base reaction. The effects of different ratios of FG/OS (ranging from 10:1 to 2:1) on the properties of films were investigated. OS improved the mechanical and barrier properties of films significantly, while the moisture content decreased as OS concentration increased. The optimum concentration was obtained at the loading amount of 1.5% (w/v) OS. FT-IR spectra revealed the covalent cross-linking between FG and OS induced by Schiff’ base reaction. Moreover, composite films had superior preservation effect on blueberry, according to the results of weight loss, total soluble solids, titratable acidity, and total anthocyanin content. Therefore, this study suggested that FG-OS double network films (FODF) has great potential in the packaging industry. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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19 pages, 4450 KiB  
Article
Tunable Structure and Properties of Segmented Thermoplastic Polyurethanes as a Function of Flexible Segment
by Manuel Asensio, Victor Costa, Andrés Nohales, Otávio Bianchi and Clara M Gómez
Polymers 2019, 11(12), 1910; https://doi.org/10.3390/polym11121910 - 20 Nov 2019
Cited by 50 | Viewed by 7214
Abstract
Segmented thermoplastic polyurethanes (PUs) were synthetized using macrodiols with different functional groups (carbonate, ester, and /or ether) as a segment with a molar mass of 1000 and 2000 g/mol, and 4,4’-diphenylmethane diisocyanate (MDI) and 1,4-butanediol as a rigid segment. The polyurethanes obtained reveal [...] Read more.
Segmented thermoplastic polyurethanes (PUs) were synthetized using macrodiols with different functional groups (carbonate, ester, and /or ether) as a segment with a molar mass of 1000 and 2000 g/mol, and 4,4’-diphenylmethane diisocyanate (MDI) and 1,4-butanediol as a rigid segment. The polyurethanes obtained reveal a wide variation of microphase separation degree that is correlated with mechanical properties and retention of tensile properties under degradation by heat, oil, weather, and water. Different techniques such as differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR), and synchrotron small-angle X-ray scattering (SAXS) were used to determine rigid-flexible segments’ phase behaviour. Retention of tensile properties determines the stability of the samples under different external factors. This work reveals that pure polycarbonate-based macrodiols induce the highest degree of phase miscibility, better tensile properties, hardness shore A, and retention of tensile properties under external agents. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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11 pages, 2294 KiB  
Article
An Immunosensor Based on Au-Ag Bimetallic NPs Patterned on a Thermal Resistant Flexible Polymer Substrate for In-Vitro Protein Detection
by Pan Wang, Shiliang Wei, Lifen Tong, Xiaohong He, Yun Bai, Kun Jia and Xiaobo Liu
Polymers 2019, 11(8), 1257; https://doi.org/10.3390/polym11081257 - 29 Jul 2019
Cited by 5 | Viewed by 2604
Abstract
Nanosensors based on flexible polymers have emerged as powerful tools for next generation smart devices in the recent years. Here, we report a facile protocol to fabricate an immunosensor supported by a thermally resistant flexible polymer substrate (polyarylene ether nitrile, PEN). The immunosensor [...] Read more.
Nanosensors based on flexible polymers have emerged as powerful tools for next generation smart devices in the recent years. Here, we report a facile protocol to fabricate an immunosensor supported by a thermally resistant flexible polymer substrate (polyarylene ether nitrile, PEN). The immunosensor is a localized surface plasmon resonance (LSPR) optical sensor for in-vitro protein detection based on anti-body coated gold-silver bimetallic nanoparticles (Au-Ag NPs) immobilized on a PEN substrate. Plasmonic spectroscopy and morphological characterization show that the Au-Ag NPs essentially exhibit a more uniform size distribution and higher quality factors than those from single-component Au NPs. Furthermore, it should be noted that the robust PEN substrate in this nanosensor acts a flexible substrate to support Au-Ag NPs and immobilize the nanoparticles via quick thermal annealing at 290 °C. Thanks to these merits, a prostate-specific antigen (PSA) concentration as low as 1 ng/mL can be specifically discriminated via the prepared PEN/Au-Au NPs, which confirms that the protocol reported in this work can be readily adapted for the construction of various flexible immunosensors for different applications. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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16 pages, 2189 KiB  
Article
Amphiphilic Acrylic Nanoparticles Containing the Poloxamer Star Bayfit® 10WF15 as Ophthalmic Drug Carriers
by Miguel Gómez-Ballesteros, Vanessa Andrés-Guerrero, Francisco Jesús Parra, Jorge Marinich, Beatriz de-las-Heras, Irene Teresa Molina-Martínez, Blanca Vázquez-Lasa, Julio San Román and Rocío Herrero-Vanrell
Polymers 2019, 11(7), 1213; https://doi.org/10.3390/polym11071213 - 19 Jul 2019
Cited by 7 | Viewed by 3553
Abstract
Topical application of drops containing ocular drugs is the preferred non-invasive route to treat diseases that affect the anterior segment of the eye. However, the formulation of eye drops is a major challenge for pharmacists since the access of drugs to ocular tissues [...] Read more.
Topical application of drops containing ocular drugs is the preferred non-invasive route to treat diseases that affect the anterior segment of the eye. However, the formulation of eye drops is a major challenge for pharmacists since the access of drugs to ocular tissues is restricted by several barriers. Acetazolamide (ACZ) is a carbonic anhydrase inhibitor used orally for the treatment of ocular hypertension in glaucoma. However, large ACZ doses are needed which results in systemic side effects. Recently, we synthesized copolymers based on 2-hydroxyethyl methacrylate (HEMA) and a functionalized three-arm poloxamer star (Bayfit-MA). The new material (HEMA/Bayfit-MA) was engineered to be transformed into nanoparticles without the use of surfactants, which represents a significant step forward in developing new ophthalmic drug delivery platforms. Acetazolamide-loaded nanocarriers (ACZ-NPs) were prepared via dialysis (224 ± 19 nm, −17.2 ± 0.4 mV). The in vitro release rate of ACZ was constant over 24 h (cumulative delivery of ACZ: 83.3 ± 8.4%). Following standard specifications, ACZ-NPs were not cytotoxic in vitro in cornea, conjunctiva, and macrophages. In normotensive rabbits, ACZ-NPs generated a significant intraocular pressure reduction compared to a conventional solution of ACZ (16.4% versus 9.6%) with the same dose of the hypotensive drug (20 µg). In comparison to previously reported studies, this formulation reduced intraocular pressure with a lower dose of ACZ. In summary, HEMA:Bayfit-MA nanoparticles may be a promising system for ocular topical treatments, showing an enhanced ocular bioavailability of ACZ after a single instillation on the ocular surface. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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14 pages, 4185 KiB  
Article
Elaboration and Characterization of Conductive Polymer Nanocomposites with Potential Use as Electrically Driven Membranes
by Leire Sangroniz, Ainara Sangroniz, Mercedes Fernández, Agustin Etxeberria, Alejandro J. Müller and Antxon Santamaria
Polymers 2019, 11(7), 1180; https://doi.org/10.3390/polym11071180 - 13 Jul 2019
Cited by 4 | Viewed by 2856
Abstract
In this work, a general, facile, and relatively low-cost method to produce electrically driven non-porous membranes by revalorization of recycled polyolefins is proposed. The polymer matrices are poly(propylene) (PP) and poly(ethylene) (PE) and their corresponding recycled samples, which are respectively mixed with carbon [...] Read more.
In this work, a general, facile, and relatively low-cost method to produce electrically driven non-porous membranes by revalorization of recycled polyolefins is proposed. The polymer matrices are poly(propylene) (PP) and poly(ethylene) (PE) and their corresponding recycled samples, which are respectively mixed with carbon nanotubes (CNT). The performances of the elaborated nanocomposites are studied by morphological, rheological, and electrical conductivity tests. The Joule heating effect is evaluated by applying an electric field and recording the corresponding temperature rise. An increase of 90 °C is obtained in certain cases, which represents the highest temperature enhancement reached so far by the Joule effect in thermoplastics, to our knowledge. The work shows a route to develop stimulus (voltage)-response (temperature) materials with low cost and with potential applications in many fields. As an example, the increase of the permeability with temperature of membranes made of the indicated nanocomposites, is analyzed. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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16 pages, 2576 KiB  
Article
Effect of Chitin Whiskers on the Molecular Dynamics of Carrageenan-Based Nanocomposites
by Marta Carsi, Maria J. Sanchis, Clara M. Gómez, Sol Rodriguez and Fernando G. Torres
Polymers 2019, 11(6), 1083; https://doi.org/10.3390/polym11061083 - 25 Jun 2019
Cited by 16 | Viewed by 3562
Abstract
Films of carrageenan (KC) and glycerol (g) with different contents of chitin nanowhiskers (CHW) were prepared by a solution casting process. The molecular dynamics of pure carrageenan (KC), carrageenan/glycerol (KCg) and KCg with different quantities of CHWs as a filler was studied using [...] Read more.
Films of carrageenan (KC) and glycerol (g) with different contents of chitin nanowhiskers (CHW) were prepared by a solution casting process. The molecular dynamics of pure carrageenan (KC), carrageenan/glycerol (KCg) and KCg with different quantities of CHWs as a filler was studied using dielectric relaxation spectroscopy. The analysis of the CHW effect on the molecular mobility at the glass transition, Tg, indicates that non-attractive intermolecular interactions between KCg and CHW occur. The fragility index increased upon CHW incorporation, due to a reduction in the polymer chains mobility produced by the CHW confinement of the KCg network. The apparent activation energy associated with the relaxation dynamics of the chains at Tg slightly increased with the CHW content. The filler nature effect, CHW or montmorillonite (MMT), on the dynamic mobility of the composites was analyzed by comparing the dynamic behavior of both carrageenan-based composites (KCg/xCHW, KCg/xMMT). Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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10 pages, 2931 KiB  
Article
Biomedical Grade Stainless Steel Coating of Polycaffeic Acid via Combined Oxidative and Ultraviolet Light-Assisted Polymerization Process for Bioactive Implant Application
by Ludwig Erik Aguilar, Ji Yeon Lee, Chan Hee Park and Cheol Sang Kim
Polymers 2019, 11(4), 584; https://doi.org/10.3390/polym11040584 - 1 Apr 2019
Cited by 12 | Viewed by 3980
Abstract
Stainless steel as a biomedical implant material has been studied in various fields and in various forms, such as vascular stents, bone plates, dental screws, and artificial hip and bone material. In this study, we used polycaffeic acid (PCA), a natural phenolic compound, [...] Read more.
Stainless steel as a biomedical implant material has been studied in various fields and in various forms, such as vascular stents, bone plates, dental screws, and artificial hip and bone material. In this study, we used polycaffeic acid (PCA), a natural phenolic compound, to coat the surface of medical grade stainless steel to provide added potential medicinal effects by virtue of its inherent anti-inflammatory, antiviral, antifibrosis, antithrombosis, and antihypertensive characteristics. We did this via UV irradiation under an alkaline state to solve the cost and time problems of other existing coating methods. The physicochemical properties of the samples were investigated through field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle, FTIR, and X-ray photoelectron spectroscopy (XPS). Surface bioactivity using NIH-3T3 cell lines were observed in vitro. We expect that the proposed methodology may contribute to the field of study of implantable metallic devices. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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18 pages, 6723 KiB  
Article
High-Performance TiO2 Nanotubes/Poly(aryl ether sulfone) Hybrid Self-Cleaning Anti-Fouling Ultrafiltration Membranes
by Zhi Geng, Xinyu Wang, Hongchuan Jiang, Leilei Zhang, Zhiting Chen, Yong Feng, Wenzhe Geng, Xia Yang, Mingxin Huo and Jing Sun
Polymers 2019, 11(3), 555; https://doi.org/10.3390/polym11030555 - 23 Mar 2019
Cited by 13 | Viewed by 3668
Abstract
A series of novel self-cleaning hybrid photocatalytic ultrafiltration (UF) membranes were fabricated to separate polyacrylamide, which is widely used as a commercial flocculant. To maximize the self-cleaning and anti-fouling properties of hybrid membranes, high surface area TiO2 nanotubes (TNTs) with excellent photocatalytic [...] Read more.
A series of novel self-cleaning hybrid photocatalytic ultrafiltration (UF) membranes were fabricated to separate polyacrylamide, which is widely used as a commercial flocculant. To maximize the self-cleaning and anti-fouling properties of hybrid membranes, high surface area TiO2 nanotubes (TNTs) with excellent photocatalytic activity were homogeneously introduced into a poly(aryl ether sulfone) matrix by chemical bonds. The chemical structure, micromorphology, hydrophilicity, separation efficiency, fouling behavior, and self-cleaning property of the prepared hybrid membranes were well characterized and evaluated. For the optimal sample, the flux recovery ratio increased from ~40% to ~80% after simulated sunlight irradiation for 20 min, which was attributable to the homogeneous dispersion and efficient photocatalytic degradation ability of TNTs. Furthermore, the intelligent fabrication strategy enhanced the anti-aging ability of the hybrid membranes via the use of a fluorine-containing poly matrix. This work provided new insight into the fabrication of high-performance self-cleaning inorganic/organic hybrid membranes. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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17 pages, 7410 KiB  
Article
Preparation and Properties of Polyvinylidene Fluoride Nanocomposited Membranes based on Poly(N-Isopropylacrylamide) Modified Graphene Oxide Nanosheets
by Xiangli Meng, Yuan Ji, Genhua Yu and Yujia Zhai
Polymers 2019, 11(3), 473; https://doi.org/10.3390/polym11030473 - 12 Mar 2019
Cited by 13 | Viewed by 3538
Abstract
The nanomaterial of graphene oxide grafting poly (N-isopropylacrylamide) (GO-g-PNIPAAm) was synthesized and PVDF/GO-g-PNIPAAm blended membranes were fabricated by wet phase inversion. In this work, a hydrophilic nanomaterial GO-g-PNIPAAm with poly(N-isopropylacrylamide) (PNIPAAm) grafted on GO, was synthesized by the atom [...] Read more.
The nanomaterial of graphene oxide grafting poly (N-isopropylacrylamide) (GO-g-PNIPAAm) was synthesized and PVDF/GO-g-PNIPAAm blended membranes were fabricated by wet phase inversion. In this work, a hydrophilic nanomaterial GO-g-PNIPAAm with poly(N-isopropylacrylamide) (PNIPAAm) grafted on GO, was synthesized by the atom transfer radical polymerization (ATRP) method. The resulting nanomaterial was confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectrum, and X-ray photoelectron spectroscopy (XPS) analysis. The synthesized GO-g-PNIPAAm was incorporated with polyvinylidene fluoride (PVDF) via phase inversion, and investigated for its temperature sensitivity, porosity, contact angle, scanning electron microscopy, and permeate properties. The water contact angle measurements confirmed that GO-g-PNIPAAm nanomaterial-endowed PVDF membranes with better hydrophilicity and thermo-responsive properties compared with those of the pristine PVDF membranes. Bovine serum albumin (BSA) adsorption experiments suggested that excellent antifouling properties of membranes were acquired after adding GO-g-PNIPAAm. The modified membranes showed good performance when the doping amount of GO-g-PNIPAAm was 0.2 wt %. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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17 pages, 1796 KiB  
Article
A Coupled Thermodynamic Model for Transport Properties of Thin Films during Physical Aging
by Hongjiu Hu, Xiaoming Fan and Yaolong He
Polymers 2019, 11(3), 387; https://doi.org/10.3390/polym11030387 - 26 Feb 2019
Cited by 5 | Viewed by 3034
Abstract
A coupled diffusion model based on continuum thermodynamics is developed to quantitatively describe the transport properties of glassy thin films during physical aging. The coupled field equations are then embodied and applied to simulate the transport behaviors of O2 and CO2 [...] Read more.
A coupled diffusion model based on continuum thermodynamics is developed to quantitatively describe the transport properties of glassy thin films during physical aging. The coupled field equations are then embodied and applied to simulate the transport behaviors of O2 and CO2 within aging polymeric membranes to validate the model and demonstrate the coupling phenomenon, respectively. It is found that due to the introduction of the concentration gradient, the proposed direct calculating method on permeability can produce relatively better consistency with the experimental results for various film thicknesses. In addition, by assuming that the free volume induced by lattice contraction is renewed upon CO2 exposure, the experimental permeability of O2 within Matrimid® thin film after short-time exposure to CO2 is well reproduced in this work. Remarkably, with the help of the validated straightforward permeability calculation method and free volume recovery mechanism, the permeability behavior of CO2 is also well elucidated, with the results implying that the transport process of CO2 and the variation of free volume are strongly coupled. Full article
(This article belongs to the Special Issue Polymeric Thin Films and Membranes)
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