Electrospun Polystyrene Research Articles

Equilibrium kinetics study of electrospun polystyrene and polystyrene-zeolite fibres for crude oil-water separation

Electrospun polystyrene, zeolite-modified polystyrene fibres and expandable polystyrene foam (EPS) were used to remove crude oil from oil-spilled water by adsorption process. Varying proportions of the adsorbent materials were used in the experiment. The polystyrene fibres were prepared from the viscous precursor solution of the expandable polystyrene foam dissolved in Xylene, using electrospinning technique. Porosimetry analyses of the adsorbents EPS foam, EPS fiber and EPS-Zeolite fiber was done using BET method. Equilibrium adsorption isotherms and kinetics were investigated. The experimental data were obtained from adsorption analyses and subsequently analyzed using Lagergren adsorption models. The kinetic data obtained were analyzed using a pseudo-first-order, pseudo-second-order equation. The experimental data were found to fit very well the pseudo-second-order kinetic model with correlation coefficient (R2) value of 0.9994 and calculated equilibrium adsorption amount (qe,expt) between 1.9763 and 9.4073mg/g. EPS-zeolite fibres showed highest adsorption efficiency (9.4073mg/g) for the removal of crude oil from oil spill more than EPS foam and EPS fibre.

Chitosan-rectorite nanospheres immobilized on polystyrene fibrous mats via alternate electrospinning/electrospraying techniques for copper ions adsorption

Chitosan (CS), as a kind of well characterized biopolymer, has been used for heavy metal adsorption due to its low cost and high efficacy. However, when used directly, chitosan particles had small surface area and weak mechanical strength which is unfavorable to metal adsorption and reused. Besides, it cannot be easily recycled that may cause a secondary pollution. In this paper, CS and layered silicate rectorite (REC) were fully mixed and the mixtures were subsequently electrosprayed nano-sized spheres, which were immobilized on the surface of electrospun polystyrene (PS) mats for metal adsorption. The morphology analysis taken from SEM confirmed that CS-REC nanospheres were loaded on the surface of PS fibrous mats. Small Angle X-ray diffraction patterns showed that the interlayer distance of REC in composite mats was enlarged by the intercalation of CS chains; such structure meant bigger surface area which was helpful for metal adsorption. The data of contact angle implied that PS mats coated with CS-REC nanospheres exhibited better hydrophilicity than PS mats, which was conductive to adsorption rate. Besides, the copper ions adsorption of composite mats was tested at different conditions including the adsorption time, the initial pH and the initial concentration of copper ion. The results demonstrated that PS mats coated with CS-REC nanospheres had the adsorption capacity up to 134mg/g. In addition, the addition of REC containing Ca2+ could also improve the metal adsorption because of cation exchange. The desorption assay indicated that PS mats immobilized with CS and CS-REC still kept high adsorption ability which retained 74% and 78% after three adsorption-desorption cycles.

Extreme Toughness Exhibited in Electrospun Polystyrene Fibers

Polystyrene (PS) commonly exhibits brittle behavior and poor mechanical properties due to the presence of structural heterogeneities promoting localized failure. The removal of this localized failure is shown here by processing PS into fibers with a range of diameters using electrospinning. Mechanical properties of individual electrospun fibers were quantified with atomic force microscopy based nanomechanical tensile testing. The resultant stress–strain behavior of PS fibers highlights considerable enhancement of mechanical properties when fiber diameter decreases below 600 nm such that polystyrene toughness increases significantly by over two orders of magnitude compared to the bulk. Consideration of the network properties of polystyrene is used to demonstrate the increase of draw ratio toward a theoretical limit and is potentially applicable to a range of glassy polymeric materials. image

Superfine powdered activated carbon incorporated into electrospun polystyrene fibers preserve adsorption capacity

A composite material consisted of superfine powdered activated carbon (SPAC) and fibrous polystyrene (PS) was fabricated for the first time by electrospinning. SPAC is produced by pulverizing powdered activated carbon. The diameter of SPAC (100–400nm) is more than one hundred times smaller than conventional powdered activated carbon, but it maintains the internal pore structure based on organic micropollutant adsorption isotherms and specific surface area measurements. Co-spinning SPAC into PS fibers increased specific surface area from 6m2/g to 43m2/g. Unlike metal oxide nanoparticles, which are non-accessible for sorption from solution, electrospinning with SPAC created porous fibers. Composite SPAC-PS electrospun fibers, containing only 10% SPAC, had 30% greater phenanthrene sorption compared against PS fibers alone. SPAC particles embedded within the polymer were either partially or fully incorporated, and the accessibility of terminal adsorption sites were conserved. Conserving the adsorptive functionality of SPAC particles in electrospun non-woven polymeric fiber scaffolding can enable their application in environmental applications such as drinking water treatment.

BODIPY Dye Embedded Electrospun Polystyrene Nanofibers for the Photocatalytic Degradation of Orange G in Industrial Wastewaters

BODIPY Dye Embedded Electrospun Polystyrene Nanofibers for the Photocatalytic Degradation of Orange G in Industrial Wastewaters

Effective SERS detection using a flexible wiping substrate based on electrospun polystyrene nanofibers

In this paper we demonstrate a flexible SERS substrate that offers effective in situ sampling by wiping directly from the surface of luggage, fruits or any surface of interest.

Effects of symmetry and the number of positive charges on the photocatalytic activity of indium phthalocyanines when embedded in electrospun fibers

Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric indium(III) phthalocyanines photosensitizers: the first consisting of one quaternized 4-pyridyloxyl and no other substituents (complex 1) and the second containing three quaternized 4-pyridylsulfanyl units and one aminophenoxy (complex 3). The asymmetry of complex 3 is additionally caused by the presence of two linking atoms (O and S). The symmetrically substituted indium(III) phthalocyanine containing four quaternized 4-pyridyloxyl units (complex 2) was also studied. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalytic transformation of 4-chlorophenol and bisphenol A. When immobilized on electrospun fibers, complexes 1, 2 and 3 gave singlet oxygen values of 0.31, 0.39 and 0.50 in water, respectively. Complex 3 showed the best photocatalytic behavior with observed rate constants of 2.8×10−3min−1 for bisphenol A and 3.8×10−3min−1 for 4-chlorophenol.

CNTs reinforced super-hydrophobic-oleophilic electrospun polystyrene oil sorbent for enhanced sorption capacity and reusability

To meet the challenges of global oil spills and oil-water contamination, the development of low-cost and reusable sorbents with good hydrophobicity and oleophilic nature is crucial. In this study, functionalized carbon nanotubes (CNTs) were wrapped in polystyrene (PS) polymer (PS-CNTs) and electrospun to create an effective and rigid sorbent for oil. Covalent modification and fluorination of CNTs improved their dispersibility and interfacial interaction with the polymer, resulting in a well-aligned CNTs configuration inside the porous fiber structure. Interestingly, the oil sorption process using PS-CNTs was observed to have two phases. First, the oil swiftly entered the membrane pores formed by interconnected nanofibers due to oleophilic properties of the micro-sized void. In the second phase, the oil not only moved to nano interior spaces of the fibers by capillary forces but also adsorbed on the surface of fibers where the latter was retained due to Van der Waals force. The sorption process fits well with the intra particle diffusion model. Maximum oil sorption capacity of the PS-CNTs sorbent for sunflower oil, peanut oil, and motor oils were 116, 123, and 112g/g, respectively, which was 42–70% higher than that of the PS sorbent without CNTs. Overall, a significant increase in the porosity, surface area, water contact angle, and oleophilic nature was observed for the PS-CNTs composite sorbents. Not only did the PS-CNTs sorbents exhibited a promising oil sorption capacity but also showed potential for reusability, which is an important factor to be considered in determining the overall performance of the sorbent and its environmental impacts.

MoSe2 Nanosheets Grown on Polydopamine‐Derived Porous Fibers: A High‐Performance Catalyst for Hydrogen Evolution Reaction

The development of platinum‐free electrocatalyst for hydrogen evolution reaction (HER) is highly essential to the large‐scale production and application of water splitting devices. Herein, a novel type of molybdenum diselenide decorated porous carbon fiber (MoSe2‐PCF) composite has been reported for HER. Notably, the unique mesoporous structure of electrospun polystyrene (PS) fibers is perfectly duplicated via the in situ self‐polymerization of dopamine by using PS fibers as the hard template, while porous carbon fibers are formed after the subsequent thermal annealing of polydopamine‐coated PS fibers. Thus obtained porous carbon fibers exhibit largely improved surface area which could provide highly conductive framework for electron transport, being an ideal substrate for the decoration of MoSe2. With maximally exposed active edge sites from the perpendicularly orientated MoSe2 nanosheets, the MoSe2‐PCF composite exhibits high catalytic activity toward HER, holding great potentials as highly efficient metal‐free electrodes for energy related applications.

Healing efficiency of polystyrene electrospun nanofibers with Grubbs’ catalyst in thermosetting composite

The study presents a novel method for the protection of Grubbs’ catalyst, by incorporation in polystyrene fibres via electrospinning technique. Epoxy-glass fibre composite with embedded self-healing agents (polystyrene fibres with Grubbs’ and microcapsules with dicyclopentadiene) was processed. Fibres retained pale purple colour during processing, revealing that fibres provided good protection of the catalyst from the amine hardener. The influence of self-healing agents’ content and thermal treatment on self-healing efficiency was investigated. Fourier transform infrared spectroscopy revealed that a polydicyclopentadiene formed at the healed interface. Thermal analysis revealed that ‘bleed’ at the healing sites from different samples had similar concentration of polydicyclopentadiene, indicating that the same amount of the catalyst has been provided to dicyclopentadiene for polymerization. This finding lead to assumption that electrospun polymer fibres enabled good dispersion of the catalyst in the composites. The low energy impact tests of the samples showed a recovery of 90% after 24 h at room temperature and up to 111% after repeated heating cycles.

A study on the potential of doped electrospun polystyrene fibers in arsenic filtration

Arsenic exposure is a global health hazard, particularly in areas with industrial wastewater runoff and high levels of naturally occurring arsenic-bearing soil. Current water filtration devices lack portability, severely limiting their use for wide-scale public health. In the present study, bone char, hydroxyapatite, and goethite were incorporated into electrospun polystyrene scaffolds to evaluate their arsenic binding or adsorption properties in a cost-effective, stable device with the potential for portability. Feasibility of incorporation for all dopants in the study was demonstrated using electron microscopy. Arsenic testing on contaminated water with either dopant alone or dopant-incorporated electrospun scaffolds demonstrated that the dopant-incorporated electrospun scaffolds increased arsenic binding over control, with a trend of increased arsenic binding over the dopant only counterparts. The results indicate that the low-cost, easily fabricated electrospun polystyrene is a prime choice for creating filter materials impregnated with metal binding or adsorbing materials for use in water filtration devices.

Repair of calvarial bone defects in mice using electrospun polystyrene scaffolds combined with β-TCP or gold nanoparticles

Non-biodegradable porous polystyrene (PS) scaffolds, composed of microfibers, have been prepared by electrospinning for the reconstruction of large bone defects. PS microfibers were prepared by incorporating β-TCP grains inside the polymer or grafting gold nanoparticles surface functionalized with mercaptosuccinic acid. Cytocompatibility of the three types of scaffolds (PS, β-TCP-PS and Au-PS) was studied by seeding human mesenchymal stem cells. Biocompatibility was evaluated by implanting β-TCP-PS and Au-PS scaffolds into a critical size (4mm) calvarial defect in mice. Calvaria were taken 6, 9, and 12 weeks after implantation; newly formed bone and cellular response was analyzed by microcomputed tomography (microCT) and histology.β-TCP-PS scaffolds showed a significantly higher cell proliferation in vitro than on PS or Au-PS alone; clearly, the presence of β-TCP grains improved cytocompatibility. Biocompatibility study in the mouse calvaria model showed that β-TCP-PS scaffolds were significantly associated with more newly-formed bone than Au-PS. Bone developed by osteoconduction from the defect margins to the center. A dense fibrous connective tissue containing blood vessels was identified histologically in both types of scaffolds. There was no inflammatory foci nor giant cell in these areas. AuNPs aggregates were identified histologically in the fibrosis and also incorporated in the newly-formed bone matrix. Although the different types of PS microfibers appeared cytocompatible during the in vitro experiment, they appeared biotolerated in vivo since they induced a fibrotic reaction associated with newly formed bone.

Electrospun polystyrene scaffolds as a synthetic substrate for xeno-free expansion and differentiation of human induced pluripotent stem cells

To realize the potential of human induced pluripotent stem cells (hiPSCs) in clinical medicine, robust, xeno-free substrates for expansion and differentiation of iPSCs are required. In the existing literature, synthetic materials have been reported that meet the requirement for non-xenogeneic substrates. However, the self-renewal and differentiation characteristics of hiPSCs are affected differently by the biocompatibility and physico-chemical properties of individual substrates. Although some rules based on chemical structure and substrate rigidity have been developed, most of these efforts are still empirical, and most synthetic substrates must still be rigorously screened for suitability. In this paper, we demonstrate an alternative concept for xeno-free expansion and differentiation of hiPSCs using synthetic substrates, which hinges on the structure-function relationship between electrospun polystyrene scaffolds (ESPS) and pluripotent stem cell growth. ESPS of differential porosity was obtained by fusing the fibers at different temperatures. The more porous, loosely fused scaffold was found to efficiently trap the cells, leading to a large number of three-dimensional (3D) aggregates. In the form of these trapped aggregates, we showed that hiPSCs could be cultured for up to 10 consecutive passages (P10) with maintenance of pluripotency, following which they could be differentiated to a chosen lineage. We believe that this novel, generic class of synthetic substrates that employs 'trapped aggregate culture' for expansion and differentiation of hiPSCs is an important conceptual advance, and would be of high interest to the readership of Acta Biomaterialia.

Antibacterial, Antiviral, and Oxygen-Sensing Nanoparticles Prepared from Electrospun Materials.

A simple nanoprecipitation method was used for preparation of stable photoactive polystyrene nanoparticles (NPs, diameter 30 ± 10 nm) from sulfonated electrospun polystyrene nanofiber membranes with encapsulated 5,10,15,20-tetraphenylporphyrin (TPP) or platinum octaethylporphyrin (Pt-OEP). The NPs prepared with TPP have strong antibacterial and antiviral properties and can be applied to the photooxidation of external substrates based on photogenerated singlet oxygen. In contrast to nanofiber membranes, which have limited photooxidation ability near the surface, NPs are able to travel toward target species/structures. NPs with Pt-OEP were used for oxygen sensing in aqueous media, and they presented strong linear responses to a broad range of oxygen concentrations. The nanofiber membranes can be applied not only as a source of NPs but also as an effective filter for their removal from solution.

The electrospinning of the copolymer of styrene and butyl acrylate for its application as oil absorbent.

Electrospun polystyrene materials have been employed as oil absorbents, but they have visible drawbacks such as poor strength at low temperature and unreliable integrity because of brittleness and insufficient cohesive force among fibers. Butyl acrylate can polymerize into flexible chains, and its polymer can be used as elastomer and adhesive material. Thereby it is possible to obtain the material that has better performance in comparison with electrospun polystyrene material through the electrospinning of the copolymer of styrene and butyl acrylate. In this work, a polymer was synthesized through suspension polymerization by using styrene and butyl acrylate as comonomers. The synthesis of the copolymer of styrene and butyl acrylate was verified through dissolution and hydrolysis experimental data; as well through nuclear magnetic resonance spectrometry. The viscous flow activation energy of the solution consisting of copolymer and N, N-dimethylformamide was determined via viscosity method and then adopted to establish the entanglement characteristics of butyl acrylate’s chain segments. Finally, in order to electrospin the copolymer solution into fibrous membrane, the effects of monomer feed ratio and spinning parameters were investigated. The prepared fibrous membrane was found to have a potential use as oil absorbent.

Spacer fabric-based exuding wound dressing – Part II: Comparison with commercial wound dressings

In this study, a three-layered composite structure based on spacer fabric was designed for absorbent wound dressings. The fabrication and selection of spacer fabrics were discussed in Part I. In this part, two selected spacer fabrics were further modified by covering a polyurethane or a polystyrene electrospun nanofibrous membrane onto their outer layer surface to form the final spacer fabric-based dressing products. In order to confirm the performance of these new spacer fabric-based dressings, the comparisons were conducted with three types of commercial wound dressings. The comparison indicators included the water contact angle, wettability, absorbency, air permeability and water vapor transmission rate. The results showed that in addition to very good water vapor and air permeability, the developed spacer fabric-based dressings had better absorbing properties than commercial foam dressings. Furthermore, their wettability was also good for application as wound dressings. The study has paved a new way to produce advanced wound dressings using three-dimensional textile structures.

Preparation of Au nanoparticles decorated polyaniline nanotube and its catalytic oxidation to ascorbic acid

With sulfonated electrospun polystyrene fiber as a template, uniform polyaniline(PANI) nanotubes were fabricated via polymerization of aniline followed by template removal. Au nanoparticles(Aunano) were decorated on the PANI nanotube successfully via auto-reduction of HAuCl4 on the PANI nanotube. The morphology of the nanotubes was characterized by means of scanning electron microscopy(SEM) and transmittance electron microscopy(TEM). By varying precursor concentration and incubation time, Aunano-PANI with different size of Aunano was obtained conveniently. Glassy carbon electrode modified with the Aunano decorated PANI nanotubes (Aunano-PANI/GCE) was prepared and used seccessfully for the catalytic oxidation of ascorbic acid(AA). The results of differential pulse voltammetry indicate that there is a good linear relationship between the peak currents and the concentrations of AA in the range of 5―3000 μmol/L, with the limit of detection of 1 μmol/L(S/N>3). There is no mutual interference between AA and dopamine. The electrode has been successfully applied in the detection of AA in vitamin C tablet sample.

Bacteria-immobilized electrospun fibrous polymeric webs for hexavalent chromium remediation in water

The development of hexavalent chromium remediating fibrous biocomposite mats through the immobilization of a hexavalent chromium reducing bacterial strain, Morganella morganii STB5, on the surfaces of electrospun polystyrene and polysulfone webs is described. The bacteria-immobilized biocomposite webs have shown removal yields of 93.60 and 93.79 % for 10 mg/L, 99.47 and 90.78 % for 15 mg/L and 70.41 and 68.27 % for 25 mg/L of initial hexavalent chromium within 72 h, respectively, and could be reused for at least five cycles. Storage test results indicate that the biocomposite mats can be stored without losing their bioremoval capacities. Scanning electron microscopy images of the biocomposite webs demonstrate that biofilms of M. morganii STB5 adhere strongly to the fibrous polymeric surfaces and are retained after repeated cycles of use. Overall, the results suggest that reusable bacteria-immobilized fibrous biocomposite webs might be applicable for continuous hexavalent chromium remediation in water systems.

Electrospun polystyrene nanofibrous membranes for direct contact membrane distillation

Hydrophobic electrospun polystyrene (PS) nanofibrous membranes were developed for desalination using the direct contact membrane distillation (DCMD) technique. These membranes were prepared from electrospinning of PS solutions in N,N-dimethyl formamide (DMF) with the addition of sodium dodecyl sulfate (SDS) as a processing aid. Effects of membrane thickness and fiber diameter on the average pore size and pore size distribution of nanofibrous membranes were systematically studied by capillary flow porometer (CFP), whereas the water contact angle and membrane porosity of these membranes were determined by contact angle meter (CAM) and gravimetric method, respectively. The resulting flux rate and permeate water quality (determined by conductivity) of membranes with different thicknesses and mean pore sizes from DCMD measurements were compared with those of commercially available polytetrafluoroethylene (PTFE) membranes using four different feed solutions, including distilled water, simulated brackish water, 35g/L NaCl solution and seawater. Effects of flow rates (i.e., 0.2 GPM, 0.3 GPM and 0.4 GPM) and feed solution temperatures (i.e., 70°C, 80°C and 90°C) on the flux rate and permeate conductivity of the optimized PS nanofibrous membrane (with a mean pore size about 0.19µm) were further investigated during a continuous 10h DCMD operation. Additionally, the mass and heat transfer coefficients of the optimized nanofibrous membranes in the DCMD operation were calculated. The results indicated that hydrophobic PS nanofibrous membranes can be produced by electrospinning for desalination by the DCMD method, leading to some unique opportunities in off the grid applications.

Utilization of Electrospun Polystyrene Membranes as a Preliminary Step for Rapid Diagnosis

Recent advances in clinical practice drive deoxyribonucleic acid (DNA) as an important class of biomarker. Monitoring the change in their concentration suggests the initiation and/or progression of various disorders. However, low quantity of DNA biomarkers in body fluids requires a delicate isolation methodology that provides efficient separation and easy handling. This study describes a newer‐generation separation technology relying on electrospun fibers of sub‐micrometer diameter of a commodity polymer for DNA biomarkers in simulative serum. Fibrous polystyrene membranes are prepared by electrospinning and they are subjected to post‐modification with Au. The composite membranes may provide a convenient environment for the removal of bovine serum albumin (BSA) from BSA and DNA mixtures. The eluent can be used as an efficient tool for detection of DNA biomarkers associated with diagnosis of numerous life‐threatening diseases. image