Use Of Polymer Films Research Articles

Swellable Plasma Polymer Films for Use in Hydrogel-Based Biomedical Devices

Swellable Plasma Polymer Films for Use in Hydrogel-Based Biomedical Devices

Zeolite‐based polymer composite films for vegetables and fruits packaging: A review

AbstractThe deterioration of fruits during production, transportation, and storage has become one of the main challenges in supplying fruits based on consumer requirements. Therefore, the application of suitable packaging containing effective additives to improve the properties of the used film, is very important. In this article, the studies were conducted on the use of Zeolite as an effective additive to improve the properties of polymer packaging films owing to its high porosity and low toxicity. The results showed that the presence of zeolite in a packaging film can lead to the improvement of visual observation and firmness, reduction of weight loss and total soluble solids (TSS), and increase in the pH of the packed fruits. The results obtained from reviewing the literature show that the use of zeolite has different effects on the gas permeation or adsorption through the packaging films which can control the degradative parameters of fruits and vegetables. Surface modifiers can increase the efficiency of zeolites in packaging films which are also evaluated in this article.Highlights Packaging of fruits with the use of polymer films and zeolite as an additive increases their shelf life. Ethylene is a flammable gas with the formula C2H4 that accelerates the fruit ripening. Zeolites are hydrated aluminosilicates of alkali or alkaline earth cations that are crystalline and microporous. Zeolites are widely used in the packaging of polymeric composites, due to their chemical structure and unique characteristics. The visual features, firmness, pH, TSS, TA, and weight loss are factors to be investigated for each fruit.

Investigation of weight loss of napa cabbage depending on the type of packaging and head weight

The investigation of the issue of extending the period of consumption of fresh napa cabbage with different head weights due to the use of polymer films is relevant. The purpose of the study was to experimentally substantiate measures to extend the consumption of napa cabbage. The products were grown and stored on a farm. Studies with napa cabbage heads were conducted using the laboratory method and the method of mathematical statistics. It is established that napa cabbage loses up to 10% of its mass during storage for 20 days of storage. Individual packaging of heads in stretch film, in comparison with storage in open form, allowed for reducing the natural loss of their mass by half, increasing the storage period to 90 days. Among the hybrids examined, the best keeping properties were identified in a hybrid characterised by a high content of dry and dry soluble substances, vitamin C, and total sugar. When examining the shelf life of napa cabbage, depending on the weight of the head, it is identified that the stretch film extends the duration of storage of heads weighing 350-700 and 750-900 g to 70 days. Natural weight loss reaches 10.8%. Heads weighing more than 900 g with such packaging are stored for 90 days with natural losses of 8.8%. Inserts made of polyethylene film with a thickness of 40 microns extended the storage time of cabbage heads weighing 350-700 g to 80 days with a weight loss of 10.1%. Heads weighing 750-900 and more than 900 g were stored for 90 days with natural mass losses of 10 and 7.8%, respectively. Storage of a mixture of napa cabbage heads of different weights in the stretch film increased the storage period to 80 days, and in polyethylene film – to 90 days with a weight loss of about 10%. These results can be used by researchers in the trade industry to extend the storage period of fruits and vegetables

A cross-linkable, organic down-converting material for white light emission from hybrid LEDs

Cinnamate-functionalised organic green emissive molecules can be UV-cured to give physically stable polymer films for use in white light hybrid LEDs.

Solution Copolymerizations of N‐Vinyl‐2‐Pyrrolidone with Acrylic Acid, Methacrylic Acid and Vinyl Acetate for Applications in Hair Cosmetics

AbstractHair care cosmetics are used for cleaning, damage prevention from external agents and making hair healthier. The use of film‐forming polymers in these formulations ensures the correction of hair cuticle imperfections and the reduction of water loss, making hair softer and thicker. For this reason, in the present work, N‐vinyl‐2‐pyrrolidone homopolymers and copolymers with acrylic acid, methacrylic acid and vinyl acetate are produced through aqueous solution polymerizations, investigating some properties of the final products and respective polymer films for use in capillary cosmetic applications. The obtained results show that the poly(N‐vinyl‐2‐pyrrolidone) (PVP) homopolymer and copolymer samples can be obtained with high molar masses, providing films that can interact appropriately with keratin. Besides that, it is shown that acrylic acid and methacrylic acid can be successfully incorporated into the PVP chains during the copolymerization reactions, resulting in the improvement of the mechanical properties of the film, but affecting negatively the polymer‐keratin interaction.

Damage to Polystyrene Polymer Film by Shock Wave Induced Bubble Collapse.

Metallic surfaces that are in contact with solutions are commonly used in numerous applications where these surfaces can be damaged by shock wave induced bubble collapse. Use of polymer films that coat such surfaces to prevent them from damage requires a better understanding of how much harm collapsing bubbles produce in the films. In this study, we report the results from coarse-grained molecular dynamics simulations to study the damage to polystyrene (PS) films coating a hard surface. The damage was caused by a collapsing nanobubble located in the proximity of the film and interacting with an impinging shock wave. This collapse produces a high-speed water jet that impacts the PS film with a greater force than the shock front and creates cavities/pits in the PS film. We observed that polymer molecules located in the jet vicinity undergo conformational extension in the direction perpendicular to the jet motion, while chain molecules in the rest of the film undergo compression. We also observed that damage to the film is sensitive to the strength of the shock wave.

INNOVATIVE DEVELOPMENT OF TECHNOLOGIES FOR THE CONSTRUCTION OF ANTIFILTRATION FACILITIES

Relevance of research. In the course of the operation of irrigation systems, there is a need to protect the hydraulic structures and the adjacent territories from filtration, which should be considered as a separate type of harmful effects of water. Filtration of water from canals and ponds leads to secondary flooding, salinization and waterlogging. Filtration of water at earth dams under certain conditions leads to the destruction of dams and the creation of emergency zones in the surrounding territories. In today's conditions of reforming the Ukrainian economy, it is particularly important to use technically reliable, environmentally sound and economically feasible filtration protection facilities in hydrotechnical construction.
 The purpose of the study is to identify priority areas for innovative development of technologies for the construction of anti-filtration facilities and to outline the main achievements of the Institute of WPLR NAAS in solving the problem of protection against filtration in hydraulic engineering in the past.
 Research methodology. The study used the method of generalization and system analysis of structural and technological solutions of complex systems.
 Research results. Priority areas of the solving one of the urgent problems of hydrotechnical construction - problems of protection against filtration are grounded in the article. It is noted that over the past 60 years, the technologies of construction of anti-filtration structures have developed significantly. The technological level of construction of anti-filtration structures was increased by qualitative improvement and quantitative increase of anti-filtration materials, constructive solutions for anti-filtration structures, technological solutions for construction of anti-filtration structures, structural solutions of the means of mechanical laying anti-filtration materials. Based on the results of the system analysis, the hierarchical subordination of structural and technological solutions for the construction of anti-filtration structures was determined. Based on the results of functional-cost analysis of structural and technological solutions, analytical dependencies were established to determine the priority areas of innovative development of technologies for construction of anti-filtration structures. The new most significant structural and technological solutions and scientific and technical developments in the construction of anti-filtration structures, which were created at the Institute of Water Problems and Reclamation of the NAAS in the past, are presented.
 Over the past 60 years the Institute has developed the following technical and technological solutions in the area of protection against harmful effects of filtration: trenchless method of laying vertical screens made of polymer film; construction of anti-filtration structures using trenchless method of laying vertical screens; construction of earth dams in a tiered way; construction of concrete film screens, soil film screens, anti-filtration hangers with the use of polymer film folded into the package; improved traditional technology of construction by the method of anti-filtration curtains made of polymer film by the wall-to-soil method. The Institute has also developed the recommendations for determining the technological standards of water losses in irrigation canals in terms of reducing the useful flow of water in them. It is established that the efficiency of the canals is not technical, but technical and operational characteristics of irrigation canals. A formula for adjusting the design efficiency of irrigation canals has been developed depending on the actual water flow in the irrigation network.

Robust Thin Film Surface with a Selective Antibacterial Property Enabled via a Cross-Linked Ionic Polymer Coating for Infection-Resistant Medical Applications.

Fabrication of new antibacterial surfaces has become a primary strategy for preventing device-associated infections (DAIs). Although considerable progress has recently been made in reducing DAIs, current antibacterial coating methods are technically complex and do not allow selective bacterial killing. Here, we propose novel anti-infective surfaces made of a cross-linked ionic polymer film that achieve selective bacteria killing while simultaneously favoring the survival of mammalian cells. A one-step polymerization process known as initiated chemical vapor deposition was used to generate a cross-linked ionic polymer film from 4-vinylbenzyl chloride and 2-(dimethylamino) ethyl methacrylate monomers in the vapor phase. In particular, the deposition process produced a polymer network with quaternary ammonium cross-linking sites, which provided the surface with an ionic moiety with an excellent antibacterial contact-killing property. This method confers substrate compatibility, which enables various materials to be coated with ionic polymer films for use in medical implants. Moreover, the ionic polymer-deposited surfaces supported the healthy growth of mammalian cells while selectively inhibiting bacterial growth in coculture models without any detectable cytotoxicity. Thus, the cross-linked ionic polymer-based antibacterial surface developed in this study can serve as an ideal platform for biomedical applications that require a highly sterile environment.

水晶振動子式ニオイセンサシステムの機能設計と開発に関するレビュー

Functional design of organic polymer thin films as the molecular recognition membrane of quartz crystal microbalance (QCM)-type odor sensor system is reviewed. The organic polymer materials which are used as the molecular recognition membrane of QCM odor sensors are selected in the view of solubility parameters. It is found that the solubility parameter is very useful to choice the organic polymers as the molecular recognition membrane of the QCM gas sensors for target gas and odor. It is also found that the use of polymer films with nano-wires is effective to increase the sensitivity of the QCM odor sensors.

INCREASING THE ACCURACY OF MEASURING AMPLITUDE IN CONTACTLESS CONTROL DEVICES OF THICKNESS POLYMER FILMS

The massive use of polymer films of different types and thickness determines the relevance of measuring their parameters, primarily the thickness, especially in the production process.Methods for measuring the polymer films thickness were analyzed. The most promising ones are acoustic and optical methods, in which one of the main parameters of the output signal of the primary transmitter is an amplitude value. During measuring the thickness of thin and ultrathin polymer films the variation range of signal amplitude decreases, which reduces amplitude measurement accuracy by increasing the impact of noise.The purpose of this work is to analyze and develop methods to improve the accuracy of measuring signals amplitude for control devices of polymer films thickness.The methods to improve the accuracy of measuring amplitude were considered. According to the results of the analysis it is proposed to use the structural method based on the amplitude and averaging coefficients. Their values are known for standard form signal, and can be defined for constant signal shape, typical in measuring the polymer films thickness. In this case, the value of the amplitude is determined by measuring average rectified (ARV) and/or root mean square (RMS) values and related coefficients. It significantly reduces the impact of noise.Structural diagram for the proposed method was developed and model researches on its basis were made. They indicate that when signal/noise ratio is in the range of 100 to 5, amplitude measurement accuracy increases more than 30 times. When signal/noise ratio is less than 5, accuracy decreases, but still 5 times higher than in traditional methods of measuring amplitude.Methods comparison for determining the amplitude by RMS and ARV values shows that when the signal/noise ratio is more than 10 the difference is insignificant. When signal/noise ratio is less than 5, better results can be obtained with ARV values and averaging coefficient. Particularly when the signal/noise ratio is 1, the error is less by almost 7 times.Thus, researches have confirmed the high efficiency of the proposed method under the impact of noise and interference, compared with traditional methods.

Avoiding Resistance Limitations in High-Performance Transparent Supercapacitor Electrodes Based on Large-Area, High-Conductivity PEDOT:PSS Films.

PSS) conducting polymer films for use as transparent supercapacitor electrodes. To facilitate this, we provide a detailed explanation of the factors limiting the performance of such electrodes. These films have a very low optical conductivity of σop = 24 S/cm (at 550 nm), crucial for this application, and a reasonable volumetric capacitance of CV = 41 F/cm(3). Secondary doping with formic acid gives these films a DC conductivity of σDC = 936 S/cm, allowing them to perform both as a transparent conductor/current collector and transparent supercapacitor electrode. Small-area films (A ∼ 1 cm(2)) display measured areal capacitance as high as 1 mF/cm(2), even for reasonably transparent electrodes (T ∼ 80%). However, in real devices, the absolute capacitance will be maximized by increasing the device area. As such, here, we measure the electrode performance as a function of its length and width. We find that the measured areal capacitance falls dramatically with scan rate and sample length but is independent of width. We show that this is because the measured areal capacitance is limited by the electrical resistance of the electrode. We have derived an equation for the measured areal capacitance as a function of scan rate and electrode lateral dimensions that fits the data extremely well up to scan rates of ∼1000 mV/s (corresponding to charge/discharge times > 0.6 s). These results are self-consistent with independent analysis of the electrical and impedance properties of the electrodes. These results can be used to find limiting combinations of electrode length and scan rate, beyond which electrode performance falls dramatically. We use these insights to build large-area (∼100 cm(2)) supercapacitors using electrodes that are 95% transparent, providing a capacitance of ∼12 mF (at 50 mV/s), significantly higher than that of any previously reported transparent supercapacitor.

Use of Polymer Films for the Recording and Long-term Storage of Information

Use of Polymer Films for the Recording and Long-term Storage of Information

Chemically robust conjugated polymer platform for thin-film sensors

To examine chemically robust thin conjugated polymer films for use as optical and conductometric sensors, we graft polythiophene and two alkyl-based derivatives to optically transparent substrates. Though structurally contrasting to other film deposition techniques, grafted polythiophene films preserve their documented absorption, luminescence and electrical properties. Photoluminescence intensities are sensitive to trace amounts of iron and iodine in solution with reasonable Stern–Volmer constants and downward sloping Stern–Volmer plots characteristic to thin-film sensors. Rising conductivities indicate chemical doping is responsible for photoluminescence quenching. We vary reaction times and solvents to optimize desired properties and produce robust polythiophene films, verified by X-ray photoemission spectroscopy, that are uniform across the substrate with thicknesses ranging from 20 to 200 nm and controllable levels of surface roughness. Due to steric effects, polythiophene and poly(3-methylthiophene) films exhibit the highest conductivities while poly(3-hexylthiophene) films exhibit greater photoluminescence efficiencies. These platforms show promise as thin films for in-solution sensing.

Polymers and single molecule fluorescence spectroscopy, what can we learn?

This tutorial review summarizes the most important results and developments in the field of polymer science by means of single molecule fluorescence spectroscopy (SMFS) at ambient temperatures. A broad range of topics will be addressed and it will be discussed which single molecule methods are suitable to get the maximum amount of information about polymer structure, polymer dynamics and the photophysics of incorporated or embedded dye molecules. In particular, we will report on the use of polymer films for immobilization of molecules, the visualization of dynamics near the glass transition temperature Tg, the reptation of polymer chains, the conformation adopted by polymer chains and the in situ observation of the polymerization reaction itself.

Improved adhesion of LDPE films to polyolefin foams for automotive industry using low-pressure plasma

The use of polymer films for technical applications has increased considerably in the last years, since they offer good balanced properties. Polymer films find many applications as individual materials or as laminates with other films, foams, membranes, etc. In these cases it is necessary to improve the low intrinsic surface energy of polymer films to ensure their optimum mechanical performance. In this work, low-pressure glow discharge plasma with different gases is used to improve the adhesive properties of a low-density polyethylene (LDPE) film, to obtain the optimum mechanical response of laminates with polyolefin foam for automotive applications (steering wheels). The results show a remarkable increase in T-peel strength of the adhesive joints. Furthermore, since automotive industry is characterized by high technical requirements, the evaluation of the durability of the adhesive joints (in terms of storage conditions: temperature and relative humidity) shows that the T-peel strength of adhesive joints is subjected to an aging process that slightly decreases their mechanical performance, but does not restrict the use of these laminates in automotive uses.

Comparison of parallel-plate and in-plane poled polymer films for terahertz sensing

We have performed calculations and measurements of the efficacy of two poling geometries of poled electro-optic (EO) polymer films for use in sensing terahertz (THz) radiation via EO sampling. Taking reflective and absorptive losses into consideration, we find that a parallel-plate (PP) poled film has a sensitivity maximum when oriented at 55 degrees to the incident probe and THz beams. In addition, we show that our in-plane (IP) poled polymer films are comparable in sensitivity to PP-poled films and discuss the potential for improving IP-poled polymer devices.

Characterization of polymer films for use in bimorph chemical sensors

In the present work white light interferometry is applied for the characterization of polymer films commonly used in bimorph chemical sensors. The study focuses on methacrylate polymers with positive tone patterning capabilities. The behavior upon exposure to controlled concentrations volatile organic compound and water vapors of thin poly (hydroxy ethyl methacrylate) (PHEMA) and poly (methyl methacrylate) (PMMA) layers was evaluated. The normalized film expansion for PHEMA, compared to PMMA, is higher in the case of water and methanol vapors, almost equal for ethanol and significantly lower in the case of acetone. This behavior could be attributed to the combination of polarity and hydrogen bonding capability of the analytes. A wide polymer film thickness range was examined and it was revealed that the normalized film expansion in both PHEMA and PMMA is nearly constant for films thicker than 100 nm and increases for thinner films.

Microcontact printing of colloidal crystals.

Patterned two-dimensional (2D) colloidal crystals have been transferred by a modified mucp technique that was based on the use of polymer film as "glue" to provide an efficient interaction between the microsphere "ink" and substrate. The versatility of this method has been demonstrated by the patterning of colloidal crystal on a nonplanar substrate and heterogeneously structured colloidal crystal film. The table of contents graphic shows an SEM image of the ordered parallel lines of 2D colloidal crystals on a polymer-coated glass tube with a 3.7 mm radius of curvature.

Growth of organic n‐conductors on thin polymer films for use in organic field effect transistors

AbstractThin films of different polymers ‐ poly(styrene) (PS), poly(methylmethacrylate) (PMMA), poly(vinylcarbazole) (PVCz), poly(vinylchloride) (PVC) and poly(vinylidene fluoride) (PVDF) ‐ were deposited by spin‐coating or by vapor deposition. On these polymers, thin films of (hexadecafluorophthalocyaninato)‐oxovanadium (F16PcVO) were prepared by physical vapor deposition. The growth of these films was monitored in situ by optical spectroscopy. The optical absorbance spectra were analyzed based on the coupling of transition dipoles to obtain information on the intermolecular arrangement of chromophores in the films. In all of these samples, the molecules are oriented with their molecular plane preferentially perpendicular to the substrate surface. This gives the desired overlap of the π‐systems for electric conductance parallel to the substrate. Differences in the interactions were detected when deposition temperatures below or above the glass transition temperature of a given polymer were compared. The morphology of the polymer films and the deposited semiconductors were investigated by atomic force microscopy and scanning electron microscopy. The influence of the chosen substrate on the film structure is determined. The optical and electric properties of the films could thereby be influenced and the applicability of such films as active layers in organic thin film transistors is discussed.

The total infrared transmittance of polymerised vinyl fluoride films for a wide range of radiant source temperature

The current growing interest on the use of polymer films is mainly attributed to their suitability as glazing and construction materials in various fields of contemporary technology. Polymerised vinyl fluoride (Tedlar) films are nowdays considered as very suitable for construction and energy applications. Most polymer films are partly transparent, showing a strongly selective absorbing behaviour at the infrared spectrum. Their total hemispherical infrared transmittance which depends on radiant source temperature and film thickness, is a very useful fundamental property for energy balance and heat transfer calculations. However it is not always possible to locate information about this property in the literature. In the present investigation the calculation of the total infrared transmittance of Tedlar films is presented, based on recent spectral transmittance measurements of commercial tedlar films for the wavelength band between 2.5–42.5 μm and for a broad range of radiant source temperatures between –20 to 500 C. Results from the present analysis were found to be in reasonable agreement with earlier data, derived for a specific film thickness and for a narrow range of radiant source temperatures by Willier.