Polymer-based Supports Research Articles

Development Status of Solar-Driven Interfacial Steam Generation Support Layer Based on Polymers and Biomaterials: A Review.

With the increasing shortage of water resources and the aggravation of water pollution, solar-driven interfacial steam generation (SISG) technology has garnered considerable attention because of its low energy consumption, simple operation, and environmental friendliness. The popular multi-layer SISG evaporator is composed of two basic structures: a photothermal layer and a support layer. Herein, the support layer underlies the photothermal layer and carries out thermal management, supports the photothermal layer, and transports water to the evaporation interface to improve the stability of the evaporator. While most research focuses on the photothermal layer, the support layer is typically viewed as a supporting object for the photothermal layer. This review focuses on the support layer, which is relatively neglected in evaporator development. It summarizes existing progress in the field of multi-layer interface evaporators, based on various polymers and biomaterials, along with their advantages and disadvantages. Specifically, mainly polymer-based support layers are reviewed, including polymer foams, gels, and their corresponding functional materials, while biomaterial support layers, including natural plants, carbonized biomaterials, and other innovation biomaterials are not. Additionally, the corresponding structure design strategies for the support layer were also involved. It was found that the selection and optimal design of the substrate also played an important role in the efficient operation of the whole steam generation system. Their evolution and refinement are vital for advancing the sustainability and effectiveness of interfacial evaporation technology. The corresponding potential future research direction and application prospects of support layer materials are carefully presented to enable effective responses to global water challenges.

Recent Advances in Anode Metallic Catalysts Supported on Conducting Polymer-Based Materials for Direct Alcohol Fuel Cells

Sustainable energy development is a major challenge, particularly when considering population increase, rising energy demands resulting from the excessive use of nonrenewable fossil fuels, and growing consequences on global pollution and climate change. It is critical to continue to develop new sources of renewable and clean energy. Direct alcohol fuel cell (DAFC) represents a technological approach that meets all the requirements in terms of energy conversion with good electrical efficiency and lower emissions of pollutants. However, it largely suffers from the poisoning of the anode catalyst caused by the accumulation of intermediate products. In this context, this review is devoted to discussing the recent progress in anode catalysts based on conducting polymers (CPs) materials for direct alcohol fuel cells, especially direct methanol and ethanol fuel cells, from the viewpoint of synthesis techniques, morphology, and catalytic performance. In the first part of this review, we will explore the most commonly used methods for preparing metal-conducting polymer-based nanocomposites, including the key factors influencing their morphology regardless of the application. The catalytic performances of mono-, bi-, and tri-metal catalysts deposited on conducting polymer-based supports for the electrooxidation of methanol and ethanol reactions are examined in detail in the second and third parts of this review. We also highlight the effect of the introduction of carbon nanomaterials into conducting polymer supports on the electrical properties and on the performance of the catalysts. Development of anode materials using nanostructured conducting polymers-based support plays a vital role in reducing catalyst loadings and should therefore shed light on the wide-scale commercialization of DAFCs. In a nutshell, this review will give readers a thorough understanding of the principles of direct alcohol fuel cells, new advancements in electrode materials based on non-precious metals, and the main challenges that should be dealt with.

Versatile microporous polymer-based supports for serial macromolecular crystallography.

Serial data collection has emerged as a major tool for data collection at state-of-the-art light sources, such as microfocus beamlines at synchrotrons and X-ray free-electron lasers. Challenging targets, characterized by small crystal sizes, weak diffraction and stringent dose limits, benefit most from these methods. Here, the use of a thin support made of a polymer-based membrane for performing serial data collection or screening experiments is demonstrated. It is shown that these supports are suitable for a wide range of protein crystals suspended in liquids. The supports have also proved to be applicable to challenging cases such as membrane proteins growing in the sponge phase. The sample-deposition method is simple and robust, as well as flexible and adaptable to a variety of cases. It results in an optimally thin specimen providing low background while maintaining minute amounts of mother liquor around the crystals. The 2 × 2 mm area enables the deposition of up to several microlitres of liquid. Imaging and visualization of the crystals are straightforward on the highly transparent membrane. Thanks to their affordable fabrication, these supports have the potential to become an attractive option for serial experiments at synchrotrons and free-electron lasers.

Highly permeable carbon nanotubes/polyamide layered membranes for molecular sieving

Traditional nanofiltration membranes (NFMs) formed by interfacial polymerization (IP) present relatively low water permeance due to the limitation of polymer-based supports. This work reports high-performance carbon nanotubes-polyamide (CNTs-PA) NFMs with interlayer and functional layer covalently coupled. These membranes feature an interpenetrating network structure, which leads to an extremely high Congo red rejection of 99.47%. The water permeance of the optimal membrane (48.98 L m-2h−1 bar−1) is much higher than most membranes with similar Congo red rejection. Meanwhile, the obtained membranes show an excellent selectivity to NaCl/dye mixed solution (the selectivity of NaCl/CR is 150.32). Moreover, this work comprehensively demonstrates the aggregation kinetics of dye molecules under different pH environments, which strongly affects the dye rejection of the CNTs-PA membrane. The membrane exhibits a switchable CR release property that the CR rejection is severely disabled (2.12%) under a strong alkaline environment and immediately re-effective (99.38%) after neutralization. Building on these findings, our work expands the possibilities of NFMs in ultrafast molecular sieving and pH-responsive separation.

Highly Transparent Cyclic Olefin Copolymer Film with a Nanotextured Surface Prepared by One-Step Photografting for High-Density DNA Immobilization.

Compared with conventional glass slides and two-dimensional (2D) planar microarrays, polymer-based support materials and three-dimensional (3D) surface structures have attracted increasing attention in the field of biochips because of their good processability in microfabrication and low cost in mass production, as well as their improved sensitivity and specificity for the detection of biomolecules. In the present study, UV-induced emulsion graft polymerization was carried out on a cyclic olefin copolymer (COC) surface to generate 3D nanotextures composed of loosely stacked nanoparticles with a diameter of approximately 50 nm. The introduction of a hierarchical nanostructure on a COC surface only resulted in a 5% decrease in its transparency at a wavelength of 550 nm but significantly increased the surface area, which markedly improved immobilization density and efficiency of an oligonucleotide probe compared with the functional group and polymer brush-modified substrates. The highest immobilization efficiency of the probes reached 93%, and a limit of detection of 75 pM could be obtained. The hybridization experiment demonstrated that the 3D gene chip exhibited excellent sensitivity for target DNA detection and single-nucleotide polymorphism discrimination. This one-step approach to the construction of nanotextured surfaces on the COC has promising applications in the fields of biochips and immunoassays.

Designing continuous flow reaction of xylan hydrolysis for xylooligosaccharides production in packed-bed reactors using xylanase immobilized on methacrylic polymer-based supports

The present study focuses on the development and optimization of a packed-bed reactor (PBR) for continuous production of xylooligosaccharides (XOS) from xylan. For this purpose, three different methacrylic polymer-based supports (Relizyme R403/S, Purolite P8204F and Purolite P8215F) activated with glyoxyl groups were morphologically characterized and screened for the multipoint covalent immobilization of a xylanase. Based on its physical and mechanical properties, maximum protein loading and thermal stability, Relizyme R403/S was selected to set up a PRB for continuous production of XOS from corncob xylan. The specific productivity for XOS at 10 mL/min flow rate was 3277 gXOS genzyme−1 h−1 with a PBR. This PBR conserved >90% of its initial activity after 120 h of continuous operation.

Synthesis of nanoporous iminodiacetic acid sorbents for binding transition metals

Iminodiacetic acid (IDAA) forms strong complexes with a wide variety of metal ions. Using self-assembled monolayers in mesoporous supports (SAMMS) to present the IDAA ligand potentially allows for multiple metal–ligand interactions to enhance the metal binding affinity relative to that of randomly oriented polymer-based supports. This manuscript describes the synthesis of a novel nanostructured sorbent material built using self-assembly of a IDAA ligand inside a nanoporous silica, and demonstrates its use for capturing transition metal cations, and anionic metal complexes, such as PdCl 4 - 2 .

Insight into the chiral recognition of warfarin enantiomers by epichlorhydrin/β-cyclodextrin polymer-based supports: determination of stoichiometry and stability of warfarin/β-cyclodextrin polymer complexes

The complexation of warfarin (W) enantiomers by a hydrosoluble high-molecular-weight β-cyclodextrin/epichlohydrin polymer (EP/β-CD polymer) was studied using HPLC with a mobile phase of methanol/0.1 M Na acetate/acetic acid (pH 4) at 22 °C. It was found that the complexes (W/β-CD unit) have a 1:1 stoichiometry. The stability constants of the complex involving each enantiomer and the polymer β-CD units were determined in the mobile phase, and the highest stability of the complex ( S-warfarin/β-CD unit) was observed. From the chromatographic separations of warfarin enantiomers on different β-CD or its derivative supports, we have deduced the role of the simultaneous presence of several glyceryl (–O–CH 2–CHOH–CH 2–O–) and dihydroxypropyl (–O–CH 2–CHOH–CH 2OH) groups on one β-CD ring in promoting the chiral recognition of warfarin enantiomers.

Preparation and Evaluation of Ricinus communis Agglutinin Affinity Adsorbents Using Polymeric Supports

A practicable and efficient procedure for preparation of Ricinus communis agglutinin (RCA) affinity adsorbents has been developed. For immobilization of RCA two different polymer-based supports, Toyopearl and TSKgel (TosoHaas), were used. RCA has been successfully immobilized onto these supports with amounts of coupled ligand between 15 and 23 mg/g dry support and corresponding coupling yields of 69–93% (w/w). The prepared affinity adsorbents were characterized concerning their binding capacity for the glycoprotein asialofetuin (ASF) and accessibility of the ligand binding sites. The high accessibility of 80% showed that steric hindrance was negligible at the present ligand density. RCA–Toyopearl was successfully applied in affinity chromatography of glycoproteins indicating its high specificity. A long-term stability test proved no change in capacity for a period of at least 12 months. High-performance affinity chromatography (HPLAC) was carried out using RCA–TSKgel. Experimental results showed that the prepared adsorbents are suitable for selective separation of glycoproteins and oligosaccharides and therefore can be used for investigations of adsorption characteristics of glycoconjugates and for laboratory-scale preparations.

Heterogeneity of Surface Energies in Reversed-Phase Perfusive Packings

The surface energetic heterogeneity of the packing media used in perfusion chromatography was investigated based on the liquid–solid adsorption information of phenol. The adsorption isotherms on two perfusive packings, POROS R1 and POROS R2, were measured by stepwise frontal experiments at varying mobile-phase concentrations and temperatures. The isosteric heat of adsorption was calculated from the isotherm data and the adsorption energy distributions (AEDs) were obtained numerically by the expectation maximization (EM) method. The adsorption isotherms corroborated the Langmuir–Freundlich (LF) isotherm well, suggesting the heterogeneity of surface energies of the perfusive medium. The analysis of the isosteric heat of adsorption indicated that this surface heterogeneity might have arisen from the differences in the pore size distributions of the perfusive particles. This observation was further confirmed by the numerically obtained adsorption energy distribution functions. Bimodal energy distribution functions were obtained for the perfusive packings, which is a reflection of the bimodal pore size distributions of the materials. In addition, it has also been found that the temperature dependence of the surface energetic heterogeneity is insignificant for such polymer-based support used in perfusion chromatography, whereas its dependence on the acetonitrile concentration in the mobile phase is rather pronounced.

That Smell in the Vaults

THAT SMELL IN THE VAULTS: THE DEGRADATION OF POLYMERS IN AV MATERIALS VINEGAR Syndrome(1), Rancid Butter Syndrome(2), Rotten Fish Syndrome -- evocative but accurate descriptions of the pervasive killers of our sound and moving image heritage. Leaving aside the well-known problems of nitrate film we are faced with the stability problems of our polymer-based supports. All polymers are subject to decay; and the cellulose nitrate, cellulose diacetate, cellulose butyrate, cellulose propionate and cellulose triacetate bases are no exception. The problem is not limited to film -- audiotape, videotape, computer tape, computer disk and other formats are subject to the same inevitable decay and destruction. Over the last few years it has come to the attention of archivists around the world that the life expectancy of our audio-visual heritage is not what we once thought it should be. Storage conditions naturally have dramatic impacts on life expectancy. We...

4885250 Enzyme immobilization and bioaffinity separations with perfluorocarbon polymer-based supports: John William Eveleigh, Robert K Kobos assigned to E I Du Pont De Nemours and Company

4885250 Enzyme immobilization and bioaffinity separations with perfluorocarbon polymer-based supports: John William Eveleigh, Robert K Kobos assigned to E I Du Pont De Nemours and Company

On-column catalysis of hydratization equilibria during liquid chromatographic analysis of acetaldehyde and formaldehyde

The aldehydes were separated by reversed phase chromatography on a polymer-based support. Acid catalysis on the column was needed to obtain sufficiently fast equilibrium between acetaldehyde and its hydrate. Deuterium labeled acetaldehyde (D3) yielded complete separation from the nonlabeled compound, probably due to a difference in hydratization. Fluorescent products were obtained by reaction between the aldehydes and a mixture of ammonia and dimedone (5.5-dimethyl-1.3-cyclohexanedione). The fluorescence was detected at 460 nm after excitation at 390 nm. A reaction time of 42 seconds at 90°C in a knitted teflon capillary produced detection limits of 0.5 and 1 ng for acetaldehyde and formeldehyde, respectively. A method for preparation of a stable reagent with low background fluorescence is described.