Polystyrene Layer Research Articles

Towards improving ELISA surfaces: SPR assessment of polystyrene modification efficiency for promoting immobilization of biomolecules

The enzyme-linked immunosorbent assay (ELISA) is a widely used diagnostic technique. In ELISA, detection of the target biomolecules is achieved through selective capture by appropriate antibody immobilized on a solid support. Our study addresses the application of surface plasmon resonance to an assessment of the polystyrene modification efficiency for promoting adsorption of biomolecules. A method facilitating the development of advanced immobilization strategies for biofunctionalization of polystyrene surface was evolved. The proposed approach uses formation of a thin layer of polystyrene over the SPR chip surface, thus enabling a detailed characterization of biomolecular interactions at the polystyrene surface.

Effect of pressure chamber variations on temperature (Te) and electron density (Ne) on nitrogen plasma diagnostics using optical emission spectroscopy

Nitrogen plasma treatment of a polystyrene layer in a vacuum chamber resulted in changes in its hydrophobicity properties. The purpose of this work was to investigate the effect of chamber pressure on nitrogen plasma treatment on the hydrophobicity properties of polystyrene surfaces. The plasma character was diagnosed by optical emission spectroscopy (OES) determining the plasma parameters, i.e. electron temperature (Te) and the electron density (Ne). Boltzmann plot method, ratio, and Stark Broadening were utilized to calculate the parameters. The hydrophobicity properties of polystyrene surfaces were measured by contact angle measurements, and polar groups studied with FTIR. The plasma diagnostic results showed that higher the chamber pressure resulted in greater intensity of the emission spectrum. The spectrum exhibits the highest intensity at the wavelength of 385.715 nm, indicating the existence of NII or N 2+ ion species. The increase of the chamber pressure declined the electron temperature but increased the electron density​​. Results of the FTIR measurements indicated the presence of the new CH 3 groups that are polar groups causing the surface to change characteristic, from hydrophobic to hydrophilic.

Разделение нефтяной эмульсии динамической мембраной с поверхностным слоем из полистирола

In this paper, we studied the parameters of the process of separation of oil emulsion using a dynamic membrane of ultrafiltration PTFEg-PSd. A polymer membrane with a dynamic layer of polystyrene particles with sizes from 55 to 72 nm was obtained on a substrate of hydrophilic polytetrafluoroethylene (PTFE). The results of scanning electron microscopy showed the formation of a layer of spherical polystyrene particles on the membrane surface. The properties of a dynamic membrane were studied: porosity, moisture capacity, and wettability. After applying the polystyrene layer, an increase in the hydrophobicity of the surface layer of the membrane was established. For membrane separation, a 1% oil emulsion was prepared by dispersing the carbonaceous oil. The retention capacity of membranes for oil products from 1% oil emulsion was 96.4%, with a specific productivity of 113 dm3/m2·h which is not inferior to the performance of a commercial UPM-100 ultrafiltration membrane. Particle sizes of the dispersed phase in a 1% oil emulsion are distributed in the range from 229 to 1476 nm, after separation of the emulsion by a dynamic membrane, oil particles with sizes from 134 to 236 nm were detected in the filtrate, which indicates the removal of the bulk of the dispersed phase from the emulsion by ultrafiltration membranes.

Raman enhancement properties of a high uniformity PS microsphere-Ag nanoparticle substrate

A structured SERS substrate with high uniformity and sensitivity was fabricated orderly by hydrophilizing the monocrystalline silicon substrate, self-assembling a layer of dense polystyrene (PS) microsphere array on the silicon, and depositing a layer (5 nm, 10 nm, 20 nm, 30 nm or 50 nm) of silver film. Rhodamine 6G (R6G) was used as a probe to characterize the performance of Raman enhancement. Experimental results show that our sample with deposition of a 5 nm silver film (PS-Ag-5) can obtain a large number of spatially distributed local electromagnetic field hot spots, with an enhancement factor of over 108, which is several orders of magnitude higher than that of other samples. The sensitivity of PS-Ag-5 to the concentration of probe molecules and the optical enhancement effect of PS microspheres were also analyzed. This novel structured substrate can achieve considerable uniformity, and the calculated relative standard deviation (RSD) of the characteristic peak at 1650 cm-1 is approximately 8%.

Facile fabrication of encryption composite materials with trilayer quasi-amorphous heterostructure

Encryption materials represent a major direction of information security, but it is challenging to realize the ideal security combining the complete hiding of complex coding, stability in transmission, camouflage, and reliable decoding. Herein, we report an innovative strategy for rationally constructing encryption composite materials with high security and portability. Compared with common colloidal photonic watermarks, our encrypted optical devices are composed of thermoplastic polyurethanes (TPU) protective layers, polystyrene (PS) switching layers and a CdS coding layer. The optical shielding properties and phase state transition of PS layers enable high-level encoding and decoding security through thermal activation of light transmittance control. Meanwhile, the CdS layer can be clearly revealed in decoding mode because of the high refractive index. Besides, the confinement protection of integrated TPU films prevents the trilayer quasi-amorphous heterostructure from damage. To establish the practical advantage, portable information carriers can be prepared for camouflage. Accordingly, the reliable encoding and decoding system, and ability to integrate with easy-to-carry products, make our composites a potentially high-security encryption device for anti-fraud technology.

Utilization of plastic waste and polystyrene in making light weight red soil fly ash bricks

The plastic industry is the important sector in India which is more valuable and playing vital role in economy of our country. Even though it is an important industry, it produces few environmental brunt causing land and water impairment with some ill effects. The methods following for dumping, leads to ground water contamination and thereby cause other adverse effects. Many investigations have been organized in this area and found that the contamination level is greater in ground water and having problem mainly in dumping area premises. In the current study, an experiment had been made to reuse the plastic waste chips in manufacturing of building materials. The objective of this project is to identify the possibilities of using the waste plastic obtained from plastic product manufacturing industry as a brick material. The various test had been carried out such as compressive strength test, crushing strength test, water absorption test, efflorescence test, hardness test, soundness test and fire test for proving the modified bricks with conventional brick. The final outcome the test results shows that the lightest brick samples among the all tested four various samples produced the strength of 68.8% greater than the third class brick and its weight is around 33% of the conventional bricks. Light weight bricks are making by using lime, fly ash, red soil, polystyrene layer, decreased the self weight of the building which improved stability in earthquake situations.

Eco-facile application of electrospun nanofibers to the oil-water emulsion separation via coalescing filtration in pilot- scale and beyond

In the present environmental study, different polymer nanofibers as coalescing filters and the effect of their type on the separation of secondary oil emulsion from oily wastewater were investigated in a semi-industrial scale. Polystyrene (PS), polyacrylonitrile (PAN), and polyamid6 (PA6) were used to be electrospun on the polyester (PET) nonwoven substrates. These nanofibers were fabricated in various spinning times. Filtration variables were examined and a system was designed. By adding the nanofiber layer to the nonwoven substrate, pressure drop and coalescing filter efficiency increased in all samples. The separation efficiency for three nanofibrous coalescing filters in 20 min electrospinning of different polymers at the same condition on polyester nonwoven as substrate such as two nonwoven layers of PET and one layer of PAN, two nonwoven layers of PET, and one layer of PA6, two nonwoven layers of PET and one layer of PS were 89.3 %, 83.3 % and 69.8 % respectively. This value was 60.6 % for the blank sample (nonwoven polyester). Hence, the mixture of two nonwoven layers of PET and one layer of PAN was selected as the suitable filter. Using the suitable coalescing filter COD decreased significantly. It diminished the potential risks related to oil discharge to the environment.

Position-Dependent Diffusion Dynamics of Entangled Polymer Melts Nanoconfined by Parallel Immiscible Polymer Films.

The morphological structure and dynamics of confined polymers adjacent to the polymer-polymer interface have a profound effect on determining the overall physical properties of polymer blends. We measured the diffusion dynamics of poly(methyl methacrylate) (PMMA) melts confined between polystyrene (PS) layers using neutron reflectivity. Combinations of various thicknesses of PMMA and deuterated PMMA (dPMMA) allowed us to experimentally reveal the nonmonotonic behavior of polymer mobility near the PS-PMMA interface. From the neutron reflectivity results, we found that the polymers adjacent to the immiscible polymer-polymer interface showed enhanced diffusion dynamics because of the repulsive interaction between PS and PMMA, whereas the polymer at local regions farther from the interface exhibited reduced dynamics. This is probably due to the nonspherical conformation of PMMA and spatial confinement near the PS-PMMA interface.

Fabrication of robust self‐cleaning superhydrophobic coating by deposition of polymer layer on candle soot surface

AbstractA facile and inexpensive way have been developed to fabricate robust self‐cleaning superhydrophobic coating by depositing polymer layer on candle soot (CS) surface using dip coating method. The stability and robustness of the CS deposited superhydrophobic surface is much weaker due to weak interaction and nonchemical bonding with the substrate. We introduced a thin layer of polystyrene, polyethylene, polypropylene (PP), and polyvinylidene fluoride on CS surface in order to improve its mechanical properties. The fabricated surfaces with the use of respective polymers exhibited water contact angles of nearly 170, 174, 175, and 171° with sliding angles of 2, 1, 1, and 3°, respectively. Although, all the polymers used in this work exhibited excellent superhydrophobic and self‐cleaning surface property, we found that the PP deposited CS surface exhibit better stability against water jet hitting and water drop impact tests. The PP deposited CS surface almost maintained their surface properties even after 50 cycles of sandpaper abrasion and 20 cycles of adhesive tape peeling tests. The mechanical durability tests confirmed that PP is a better polymer to improve the long‐term durability of CS surface. Therefore, this simple, time saving, and inexpensive method for fabricating superhydrophobic coating can be used for potential industrial application.

Application of pH Indicator Label based on Beetroot Color for Determination of Milk Freshness

Introduction: Applying of a new indicator in food packaging can be effective to inform consumers about the freshness and quality of the products. Material and Methods: In the current study, a new milk freshness label was investigated containing beetroot color and multi layers of polystyrene. The label characteristics were investigated by estimating color number, release test, and scanning electron microscopy (SEM). The total bacterial count, pH, lactic acid concentration in milk, and label color number were measured using standard plate count, pH meter, titration of acidity, color analysis software, and UV spectrophotometry on days 0, 3, 4, 5, 6, and 7 at refrigerator temperature (4 ± 0.2°C). Results: The label reacted to total bacterial count and pH changes with a visible color during milk spoilage. A positive correlation was found between the label color changes, total bacterial count, and pH. The color of label turned from dark red to light brown, which was related to the chemical changes and bacterial count of milk. Conclusion: According to this simple, visible, and affordable label, the shelf life of pasteurized milk was estimated as five days.

Dynamic Membrane with a Polystyrene Surface Layer for Ultrafiltration of Spent Coolant Lubricant

Ultrafiltration membranes with a dynamic layer of polystyrene particles 55–72 nm in size were obtained on a hydrophilic polytetrafluoroethylene substrate. The results of scanning electron microscopy showed the formation of a layer of spherical particles on the membrane surface. After applying a layer of polystyrene to the surface of a polytetrafluoroethylene substrate, a decrease in the specific productivity of the membranes is observed, and an increase in the hydrophobicity of the surface layer of the membrane is revealed. The dynamic membrane was used to separate spent cutting fluid (coolant). The separation efficiency of the emulsion was evaluated by the removal of petroleum products and fatty acids. The retention capacity of the membrane for oil products from the spent emulsion was 95% with a specific productivity of 167 dm3 /(m2· hr), which is not inferior to the performance of commercial ultrafiltration membranes. The HPLC method was used to study the content of fatty acids in the emulsion and its filtrates. The retention capacity of the dynamic membrane for fatty acids was more than 68%.

Structural and electromagnetic properties of Fe2Co-multi-walled carbon nanotubes-polystyrene based composite

Here, we report on the synthesis, characterization, and electromagnetic properties of the composites based on Fe2Co alloy nanoparticles, multi-walled carbon nanotubes (MWCNTs), and polystyrene (PS). The absorbing electromagnetic characteristics of Fe2Co/MWCNT-PS composites in the frequency range of 1–18 GHz have been tuned by controlling their dielectric and magnetic properties. For this, Fe2Co/MWCNT hybrids with a controlled composition and particle size of the Fe2Co alloy have been obtained by thermal decomposition of iron and cobalt carbonyls on the surface of MWCNTs with subsequent production of Fe2Co/MWCNT-PS membranes by vacuum filtration. The optimization of the conditions of the Fe2Co alloy particles formation as well as the study of the structure and morphology of the hybrids and membranes based on them have been carried out using HRTEM, HAADF-STEM, SEM, XRD, and TPD. The effect of the calcination temperature on the evolution of the chemical composition, structure, size, and morphology of supported Fe2Co nanoparticles has been thoroughly studied. In order to enhance the shielding properties of the material, a multilayer composite structure has been proposed and optimized, consisting of five alternating layers of Fe2Co/MWCNT-PS membranes and dielectric layers (neat PS) localized on a metal surface. The simulation results show that the proposed five-layer material, consisting of three layers of Fe2Co/MWCNT-PS membranes with thickness of 0.1 mm and two layers of PS with thickness of 0.5 mm, shows the highest efficiency of electromagnetic interference shielding (−14.2 dB at 17.5 GHz) as compared to a similar composite consisting of MWCNT-PS membranes (−5.4 dB at 17.5 GHz). Such multilayer structure is cost-effective and lightweight, which makes it a perspective material for EMI shielding.

Impact of the imperfection of thermal insulation on structural changes of thin-layer façade claddings in ETICS

The article presents research studies carried out on ETICS in the accelerated aging chamber, with gaps used as the predetermined imperfections. Based on the conducted research, Authors defined mineralogical changes taking place in plasters and porosimetry tests illustrating the changes resulting from the imperfections introduced to the system. Based on the research, it was found that over time, for mineral plasters, open porosity increases much more than for polymer plasters. During the aging process in acrylic plasters there is a strong rearrangement of micropores towards mesopores. In places of imperfection in the polystyrene layer there are higher amounts of carbonate salts compared to places outside of gaps. This effect is clearly visible in mineral plaster, where CaCO3 calcite salts are formed, and in acrylic plaster salts of CaMg (CO3)2 dolomite.Features such as water vapor diffusion coefficient, water absorption, interlayer adhesion, and other impact resistance were also determined. Discontinuities in the insulation material already 2 mm wide cause an increase in the vapor-permeability of the entire system, creating the so-called diffusion bridges. In terms of system durability, the weakest element is the plaster layer and the contact zone with the primer. Of the tested systems, the best durability was demonstrated by the variant in which a primer based on styrene acrylic resin was used as the bonding layer.

Surface-Grafted Hyperbranched Polyglycerol Coating: Varying Extents of Fouling Resistance across a Range of Proteins and Cells.

Hyperbranched polyglycerol (HPG) was previously investigated as a nonfouling hydrophilic grafted layer on biomaterial surfaces, analogous to the well-known poly(ethylene oxide) (PEO), but the range of adsorbing cells and proteins tested was limited and at times the assays used were not the most sensitive. Thus, the questions arise whether HPG-grafted layers can indeed efficiently resist adsorption of a wider range of adsorbing biological entities, and how would different biological entities interact with such a coating. An HPG coating of 25 nm thickness was grafted onto a spin-coated and plasma-treated polystyrene (PS) layer on a silicon wafer substrate; this provided a well-suited system for surface analyses by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and atomic force microscopy (AFM), which verified the presence of a uniform, smooth grafted HPG layer. Adsorption of bovine serum albumin, lysozyme, fibrinogen, and endothelial cell growth medium 2 (EGM2) was reduced by >90%, with the adsorbed amounts close to the detection limit of XPS but still detectable by ToF-SIMS using principal component analysis. With human serum, however, the reduction in adsorption was slightly less pronounced. Smooth muscle cells (SMCs) and fibroblasts were virtually unable to attach onto the grafted HPG layer, with >99% reductions at 6 h compared with plasma-treated PS; the few attached cells remaining rounded and unable to spread. Their attachment might have resulted from coating defects. Testing with full blood showed that unlike for the control surface (plasma-treated PS), platelets did not adhere to the HPG surface, but there was attachment of some cells that stained CD11b positive and likely are neutrophils. Cells of the fungal organism Candida albicans were also able to attach onto the HPG surface to a limited extent, but in contrast to the control surface, the attached cells on HPG did not form hyphal extensions and thus seem to be compromised in their ability to invade and to form biofilms. Our data suggest that "low-fouling" is a better term than nonfouling for a grafted HPG layer as the resistance to adsorption is not uniform across a range of proteins and cells. It is also important in future work to study whether the cells that do attach can still exert their normal functions; our observation of the absence of hyphal extensions for C. albicans suggests that this may not be so. Hence, the potential utility of a grafted HPG layer may be not just a function of adsorbed amounts but also of the functionality of adsorbed proteins and cells.

Preparation and Characterization of Aluminum‐Lithium Alloy Powder Coated by In‐situ Polymerization of Styrene

AbstractAluminum‐lithium alloy powder has broad application prospects in the field of energetic materials due to its good thermal performance. However, the high reactivity of lithium and the incompactness of the surface oxide layer result in the continuous oxidation of the active metal during storage, thereby deteriorating the thermal performance of the powder. In this paper, a layer of polystyrene (PS) was successfully coated on the surface of Al‐10Li (10 wt.%) alloy powder by in‐situ polymerization of styrene (St). According to an orthogonal test, the optimum coating conditions for protection factor were as follows: m(St)/m(Al‐10Li) was 1 : 1; m(AIBN)/m(St) was 5 %; the reaction temperature was 75 °C; the reaction time was 4 h. The structure, surface morphology and thermal properties were characterized by XPS, FTIR, SEM and TG‐DTA. Furthermore, the aging stability of powders were studied by TG‐DTA. The results showed that the decay rate of the weight increase of the active metal of Al‐10Li alloy powder decreased significantly after coating, which demonstrated that the polystyrene coating effectively protected the active metal of Al‐10Li alloy powder, prevented pre‐oxidation of Al‐10Li alloy powder in air and improved its storage stability.

Heat-transfer ('iron-on') photocatalytic films

The simple preparation of nanoparticulate CdS and TiO2 photocatalytic (PC) films embedded in a thin (2.5 μm) layer of polystyrene (PS), i.e. PC-PS films, is described. These CdS-PS, or TiO2-PS, films are then readily and easily transferred onto a range of different common flexible materials, such as many different plastics and fabrics, using the heat from an iron. In all cases the heat-transferred PC-PS films appear physically robust, as demonstrated by the 3 M Scotch Tape test, and, for the same PC, exhibit a similar photocatalytic activity, regardless of the material it is ironed onto. The photocatalytic activities of these iron-on films are demonstrated using cotton as the material support. Thus, the CdS-PS-Cot film is used to photoreduce methyl orange, methyl viologen and water using visible light (415 nm) and a sacrificial electron donor (ascorbate or EDTA). The TiO2-PS-Cot film is used to effect the same reduction reactions, but with UVA light (365 nm). The TiO2-PS-Cot film is also able to photocatalyse the oxidation of methylene blue and NO by air. In most cases there is little or no loss of activity with repeated use. Encouragingly, the non-optimised TiO2-PS-Cot film appears more active than the commercial flexible polymeric photocatalytic film Purify Mesh 30 (Taiyo Europe GmbH).

Roles of structural and chemical defects in graphene on quenching of nearby fluorophores

Oxidation scanning probe lithography was used to systematically fabricate graphene/defective graphene ribbon arrays on a graphene sheet. The tribological, structural, and chemical natures of the defects created by o-SPL were characterized using lateral force microscopy (LFM), micro-Raman (μ-RS) and micro-X-ray spectroscopy (μ-XPS), respectively. While LFM revealed all fabricated patterns exhibited increase in friction, μ-RS and μ-XPS analysis showed that a transition of defect type from structural to chemical defects occurred in the defective graphene ribbons at a threshold voltage (8.5 V). Subsequently, micro-photoluminescence (μ-PL) quenching spectroscopy was measured for a thin layer of polystyrene containing isolated fluorophores (MEH-PPV) spin cast on the ribbon patterns. Whilst the quenching efficiency was suppressed more significantly as defect concentration increased, for pure structural defects, the μ-PL lifetime varied linearly with defect concentration and then saturated to a constant as chemical defects dominated. Among all oxygen related functional groups, the presence of CO bonds led to greatly reduced quenching efficiency while simultaneously reducing the strong blue spectral shift seen for pure graphene with the spectrum at higher CO bond concentration approaching to pristine MEH-PPV. This work demonstrated that local chemical and structural composition in 2D quencher strongly affects the quenching efficiency and dynamics.

Insulator as Efficient Hole Injection Layer in Perovskite Light‐Emitting Device via MIS Contact

AbstractPolymer insulator is employed as efficient hole injection layer (HIL) in lead halide perovskites light‐emitting diodes (PeLEDs) for the first time, by revealing that metal–insulator–semiconductor (MIS) contact is responsible for the hole‐injection mechanism in PeLEDs with indium tin oxide (ITO)/insulator/perovskite structure. For MIS contact of ITO/insulator/perovskite, the electric field is concentrated in the insulator layer, thereby reducing the tunneling distance from ITO to perovskite. By studying the transient current response, it is confirmed that the accumulation of both electrons and ions at the insulator/perovskite interface is responsible for the screening of electric field. With polystyrene (PS) as hole injection layer, the device exhibits a much better device performance than that of PeLEDs with regular polyvinylcarbazole (PVK) HIL, even though the resistivity of PS is 5 orders of magnitude higher than that of PVK, which confirms the universal applicability of MIS contact. By optimizing the thickness of PS layer, the performance of FAPbBr3‐based device achieves a turn‐on voltage of 2.8 V, a peak luminous efficiency of 44.7 cd A−1, and an external quantum efficiency of 10.6%.

Influence of the Nitrogen exposure time to the plasma treatment on the wettability of polystyrene surfaces

The wettability of material can change from hydrophobic to hydrophilic when treated using plasma nitrogen. The present work investigated the influence of the plasma treatment duration on the modification of polystyrene’s surface coating on a glass surface. The polystyrene layer was produced by means of spin coating method with the rotational speed of 3000 RPM for 1 minute. The plasma was established by a 2 MHz RF generator at the power of 40 watts, pressure of 0.3 Torr, flow rate 40 mL/min. The samples were treated at various exposure time which were 2 min, 5 min, 10 min, and 15 min. The wettability of the polystyrene was measured using a contact angle measurement before and after the nitrogen plasma treatment. Polar functional groups related to the wettability were observed by a Fourier Transform Infrared (FTIR). The longer the treatment duration, the smaller the contact angle was observed. A very low contact angle of 6.42° was achieved at a power of 40 watt at 0.3 torr for the exposure time of 15 min. This means that the surface of the polystyrene changed to super hydrophilic or super wetting. The FTIR results show the spectra of NH2 and C-H functional group at the wavenumber of 3485 cm1 and 2962 cm1, respectively. These functional groups indicate the existence of the polar groups, which contribute to the change of surface hydrophobicity into hydrophilicity.

Synthesis and Characterization of a Multilayer Membrane with Surface Layers for Water Desalination

Multilayer dynamic membranes with a surface layer of polystyrene for the membrane desalination of water have been synthesized in this study. The dynamic layer is formed from polystyrene particles with a particle size of 55–92 nm that are suspended in a filtered aqueous solution of acetone with a pH of 5. The stability of the dynamic layer is provided by a heat treatment of the membrane at a temperature of 50°C for 10 min. The treatment leads to the compaction of the dynamic layer of the membrane. With an increase in the number of dynamic layers, the membrane flux decreases. After the deposition of each subsequent layer, the membrane flux decreases twofold. Thus, the flux of a four-layer nylon–polystyrene (nylon–PS) membrane with respect to distilled water is 142 dm3/(m2 h). The rejection ability of the membranes with respect to Cl–, NO3–, $${\text{SO}}_{{\text{4}}}^{{{\text{2}} - }},$$$${\text{NH}}_{{\text{4}}}^{ + },$$ K+, Na+, Ca2+, and Mg2+ ions from a model solution with a total salinity of 433 mg/dm3 is determined. The rejection ability with respect to singly charged and doubly charged ions is 58 and more than 80%, respectively, at a high flux of 118 dm3/(m2 h).