Polymer Thin Films and Membranes

A special issue of Polymers (ISSN 2073-4360).

Deadline for manuscript submissions: closed (30 December 2011) | Viewed by 51586

Special Issue Editor

Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7202, USA
Interests: Solution, diffusion and permeation; separation membranes; electronic and electrochemical membranes; degradation and other environmental effects on polymers; mechanical properties, deformation and fatigue of polymers; multi-component polymer systems; adhesion and adhesives, sealants and coatings; surface science and technology
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Special Issue Information

Dear Colleagues,

Synthetic membrane technology has achieved a startling rate of development over the last three decades. Many, if not most, of the membrane materials useful for separation processes, drug release, reactor media, and other applications are dependent on the formation and properties of thin films, often ultra-thin surface or interfacial films. Our understanding of these systems involves knowledge of the relationships between materials composition, structure and properties as affected by processing and end-use conditions. A better understanding of the scientific basis of these relationships would serve as a stimulus and guide for obtaining even more dramatic systems and applications. Areas of great promise and much accomplishment are the substitution of synthetic materials for natural biological or botanical membranes, extension of the scope of viable separation membrane applications and formation of complex membrane reactor systems. All of these areas, and others, would benefit greatly from such an increase in knowledge. This Special Issue is intended to provide a means for communicating studies that increase our scientific knowledge of thin film and membrane systems. Its content also will reflect advances reported in other relevant Special Issues of Polymers.

Prof. Dr. Charles Rogers
Guest Editor

Keywords

  • membranes
  • thin films
  • interfacial phenomena
  • penetrant-polymer interactions
  • natural membranes
  • membrane reactors
  • membrane separations
  • selective permeation
  • separation of isomeric and racemic mixtures

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Published Papers (4 papers)

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Research

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5904 KiB  
Article
Variational Models of Network Formation and Ion Transport: Applications to Perfluorosulfonate Ionomer Membranes
by Nir Gavish, Jaylan Jones, Zhengfu Xu, Andrew Christlieb and Keith Promislow
Polymers 2012, 4(1), 630-655; https://doi.org/10.3390/polym4010630 - 24 Feb 2012
Cited by 35 | Viewed by 7346
Abstract
We present the functionalized Cahn-Hilliard (FCH) energy, a continuum characterization of interfacial energy whose minimizers describe the network morphology of solvated functionalized polymer membranes. With a small set of parameters the FCH characterizes bilayer, pore-like, and micelle network structures. The gradient flows derived [...] Read more.
We present the functionalized Cahn-Hilliard (FCH) energy, a continuum characterization of interfacial energy whose minimizers describe the network morphology of solvated functionalized polymer membranes. With a small set of parameters the FCH characterizes bilayer, pore-like, and micelle network structures. The gradient flows derived from the FCH describe the interactions between these structures, including the merging and pinch-off of endcaps and formation of junctions central to the generation of network morphologies. We couple the FCH gradient flow to a model of ionic transport which incorporates entropic effects to localize counter-ions, yielding a flow which dissipates a total free energy, and an expression for the excess electrochemical potential which combines electrostatic and entropic effects. We present applications to network bifurcation and membrane casting. Full article
(This article belongs to the Special Issue Polymer Thin Films and Membranes)
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319 KiB  
Article
Effects of Emulsion-Based Resonant Infrared Matrix Assisted Pulsed Laser Evaporation (RIR-MAPLE) on the Molecular Weight of Polymers
by Ryan D. McCormick, Jeremy Lenhardt and Adrienne D. Stiff-Roberts
Polymers 2012, 4(1), 341-354; https://doi.org/10.3390/polym4010341 - 01 Feb 2012
Cited by 33 | Viewed by 9577
Abstract
The molecular weight of a polymer determines key optoelectronic device characteristics, such as internal morphology and charge transport. Therefore, it is important to ensure that polymer deposition techniques do not significantly alter the native polymer molecular weight. This work addresses polymers deposited by [...] Read more.
The molecular weight of a polymer determines key optoelectronic device characteristics, such as internal morphology and charge transport. Therefore, it is important to ensure that polymer deposition techniques do not significantly alter the native polymer molecular weight. This work addresses polymers deposited by resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE). By using a novel emulsion-based target technique, the deposition of smooth, contiguous films with no evidence of chemical degradation have been enabled. However, structural degradation via a reduction in molecular weight remains an open question. The common polymer standard, PMMA, and the optoelectronic polymers, P3HT and MEH-PPV, have been characterized before and after emulsion-based RIR-MAPLE deposition via gel permeation chromatography to determine if RIR-MAPLE affects the deposited polymer molecular weight. Proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy measurements have also been conducted to verify the absence of chemical degradation. These measurements verify that there is no chemical degradation of the polymers, and that PMMA and P3HT show no structural degradation, but MEH-PPV exhibits a halving of the weight-averaged molecular weight after RIR-MAPLE deposition. Compared with competing laser deposition techniques, RIR-MAPLE is shown to have the least effect on the molecular weight of the resulting thin films. Full article
(This article belongs to the Special Issue Polymer Thin Films and Membranes)
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1957 KiB  
Article
Mechanical Properties and Adhesion of a Micro Structured Polymer Blend
by Brunero Cappella
Polymers 2011, 3(3), 1091-1106; https://doi.org/10.3390/polym3031091 - 15 Jul 2011
Cited by 22 | Viewed by 7867
Abstract
A 50:50 blend of polystyrene (PS) and poly(n-butyl methacrylate) (PnBMA) has been characterized with an Atomic Force Microscope (AFM) in Tapping Mode and with force-distance curves. The polymer solution has been spin-coated on a glass slide. PnBMA builds a uniform film on the [...] Read more.
A 50:50 blend of polystyrene (PS) and poly(n-butyl methacrylate) (PnBMA) has been characterized with an Atomic Force Microscope (AFM) in Tapping Mode and with force-distance curves. The polymer solution has been spin-coated on a glass slide. PnBMA builds a uniform film on the glass substrate with a thickness of @200 nm. On top of it, the PS builds an approximately 100 nm thick film. The PS-film undergoes dewetting, leading to the formation of holes surrounded by about 2 µm large rims. In those regions of the sample, where the distance between the holes is larger than about 4 µm, light depressions in the PS film can be observed. Topography, dissipated energy, adhesion, stiffness and elastic modulus have been measured on these three regions (PnBMA, PS in the rims and PS in the depressions). The two polymers can be distinguished in all images, since PnBMA has a higher adhesion and a smaller stiffness than PS, and hence a higher dissipated energy. Moreover, the polystyrene in the depressions shows a very high adhesion (approximately as high as PnBMA) and its stiffness is intermediate between that of PnBMA and that of PS in the rims. This is attributed to higher mobility of the PS chains in the depressions, which are precursors of new holes. Full article
(This article belongs to the Special Issue Polymer Thin Films and Membranes)
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2199 KiB  
Review
Water Soluble Polymers as Proton Exchange Membranes for Fuel Cells
by Yun-Sheng Ye, John Rick and Bing-Joe Hwang
Polymers 2012, 4(2), 913-963; https://doi.org/10.3390/polym4020913 - 26 Mar 2012
Cited by 164 | Viewed by 25972
Abstract
The relentless increase in the demand for useable power from energy-hungry economies continues to drive energy-material related research. Fuel cells, as a future potential power source that provide clean-at-the-point-of-use power offer many advantages such as high efficiency, high energy density, quiet operation, and [...] Read more.
The relentless increase in the demand for useable power from energy-hungry economies continues to drive energy-material related research. Fuel cells, as a future potential power source that provide clean-at-the-point-of-use power offer many advantages such as high efficiency, high energy density, quiet operation, and environmental friendliness. Critical to the operation of the fuel cell is the proton exchange membrane (polymer electrolyte membrane) responsible for internal proton transport from the anode to the cathode. PEMs have the following requirements: high protonic conductivity, low electronic conductivity, impermeability to fuel gas or liquid, good mechanical toughness in both the dry and hydrated states, and high oxidative and hydrolytic stability in the actual fuel cell environment. Water soluble polymers represent an immensely diverse class of polymers. In this comprehensive review the initial focus is on those members of this group that have attracted publication interest, principally: chitosan, poly (ethylene glycol), poly (vinyl alcohol), poly (vinylpyrrolidone), poly (2-acrylamido-2-methyl-1-propanesulfonic acid) and poly (styrene sulfonic acid). The paper then considers in detail the relationship of structure to functionality in the context of polymer blends and polymer based networks together with the effects of membrane crosslinking on IPN and semi IPN architectures. This is followed by a review of pore-filling and other impregnation approaches. Throughout the paper detailed numerical results are given for comparison to today’s state-of-the-art Nafion® based materials. Full article
(This article belongs to the Special Issue Polymer Thin Films and Membranes)
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