Polyethylene Glycol Polymers Research Articles

Influence of polyethylene glycol on the aggregation/clouding phenomena of cationic and non-ionic surfactants in attendance of electrolytes (NaCl & Na2SO4): An experimental and theoretical analysis

Abstract Herein, multiple techniques were employed to gain an accurate and deep understanding for the interaction between synthetic polymer polyethylene glycol 400 (PEG 400) and surfactant (TTAB/Triton X-100 (TX-100)) in electrolytes or electrolytes free medium. Critical micelle concentration (cmc) and extent of counterion binding (β) over the 298.15 to 318.15 K temperature range were determined and thereby the degree of interaction between PEG 400 and TTAB has been estimated. The cmc of pure TTAB in H2O exhibits U-like variation with the escalation of temperature. Assessed cmc values of TTAB/TTAB + PEG 400 mixture in water as well as in NaCl solution enhance monotonically with temperature. The cmc values of TTAB + PEG 400 mixture in Na2SO4 solution exhibit reversed U-shaped variation with escalation of temperature. Estimated cmc values of TTAB + PEG 400 mixture in occurrence of NaCl/Na2SO4 were decreased in comparison to aqueous medium while at a fixed concentration of salts and particular temperature the magnitudes follow the order: cmcNaCl > cmcNa2SO4. The estimated values of Gibbs free energy (∆Gmo) & enthalpy (∆Hmo) of micellization were negative almost in each case. The values of ∆Hmo and ∆Smo indicate the presence of both hydrophobic & electrostatic interactions between PEG 400 and TTAB. Executed CP of TX-100 was reduced in the existence of PEG 400 almost in each case. The values of Gibbs free energy of clouding (∆Gco) were positive in all cases. The entropy-enthalpy compensation was observed both for aggregation of TTAB and clouding of TX-100. The atomic level interacting mechanism of PEG 400-surfactant system in salt and aqueous environment was disclosed by means of molecular dynamics simulation, which showed a good agreement with the experimental results.

Drop freezing: Fine detection of contaminants by measuring the tip angle

In this Letter, we show that the shape of a freezing drop of water can be sensitive to the presence of impurities. We measure the tip angle of water drops frozen on a cold plate. The fine changes in the tip angle are robustly captured by our image analysis method, which shows a deviation from that of pure water in solutions with salt (NaCl), polymer polyethylene glycol, and surfactant tetradecyltrimethylammonium bromide starting at concentrations of 10−6, 10−4, and 10−6 M, respectively. The method could be adapted into a portable water purity tester, but this work also highlights the complexity of water freezing as it is influenced by trace concentrations of impurities.

The effect of chitosan and PEG polymers on stabilization of GF-17 structure: A molecular dynamics study

We examine the interactions of chitosan and polyethylene glycol (PEG) with antimicrobial peptide GF-17 to identify a suitable carrier to improve the peptide drug delivery systems. To this end, the molecular dynamics simulations are used to determine the interactions of a typical antimicrobial peptide GF-17 with the chitosan and PEG polymers. The findings indicate the great potential of the peptide to maintain its secondary structure in the adjacent to chitosan polymers. During the interaction with chitosan polymers, the structure of the peptide has smaller fluctuations compared to the PEG polymers. Also, in the presence of both the polymers, the PEG polymers are situated closer to the peptide than chitosan polymers. Moreover, the analysis indicates that the acidic residues and phenylalanine play a crucial role in peptide-polymer interactions. This research provides a valuable insight into the design of polymer surfaces for drug delivery applications such as controlled-release peptide delivery systems.

Fabrication of chitosan–polyethylene glycol nanocomposite films containing ZIF-8 nanoparticles for application as wound dressing materials

Biocompatible nanocomposite films based on chitosan (CS) and polyethylene glycol (PEG) polymers containing cephalexin (CFX) antibiotic drug and zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) were designed and fabricated to develop wound dressing materials capable of controlled drug release. Swelling experiment was performed in three acidic, neutral, and alkaline solutions. The tensile strength test reflected that upon increasing the NPs loading within the films, the tensile strength was enhanced but the elongation at break was diminished. The release of the CFX was intensively increased within approximately 3, 8, and 10 h (burst release) in acidic, neutral, and alkaline media, respectively while after that the CFX was smoothly released over time (sustained release). The antibacterial activities of all films were examined against Gram-positive (S. aureus, B. cereus) and Gram-negative (E. coli, P. aeruginosa, and Acinetobacter) bacteria frequently found in the infected wounds. Moreover, the MTT assay revealed that all films had high cell viabilities towards the L929 fibroblast cells confirming these nanocomposites could be used as favorable wound dressing materials. Finally, the film containing 4% ZIF-8 NPs (film 5) was chosen as the best sample due to it revealed appropriate mechanical properties, swelling, drug release and cell viability among all samples examined.

A 3D Bioprinted Pseudo-Bone Drug Delivery Scaffold for Bone Tissue Engineering.

A 3D bioprinted pseudo-bone drug delivery scaffold was fabricated to display matrix strength, matrix resilience, as well as porous morphology of healthy human bone. Computer-aided design (CAD) software was employed for developing the 3D bioprinted scaffold. Further optimization of the scaffold was undertaken using MATLAB® software and artificial neural networks (ANN). Polymers employed for formulating the 3D scaffold comprised of polypropylene fumarate (PPF), free radical polymerized polyethylene glycol- polycaprolactone (PEG-PCL-PEG), and pluronic (PF127). Simvastatin was incorporated into the 3D bioprinted scaffolds to further promote bone healing and repair properties. The 3D bioprinted scaffold was characterized for its chemical, morphological, mechanical, and in vitro release kinetics for evaluation of its behavior for application as an implantable scaffold at the site of bone fracture. The ANN-optimized 3D bioprinted scaffold displayed significant properties as a controlled release platform, demonstrating drug release over 20 days. The 3D bioprinted scaffold further displayed formation as a pseudo-bone matrix, using a human clavicle bone model, induced with a butterfly fracture. The strength of the pseudo-bone matrix, evaluated for its matrix hardness (MH) and matrix resilience (MR), was evaluated to be as strong as original bone, having a 99% MH and 98% MR property, to healthy human clavicle bones.

Deconstructing poloxamer and poloxamine block copolymers to access poly(ethylene glycol) and poly(propylene oxide)-based thermoresponsive polymers

Poloxamer (Pluronic®) and poloxamine (Tetronic®) are commercially important block copolymers composed of polypropylene oxide (PPO) and polyethylene glycol (PEG) segments. Due to the difference in chemical polarity of the two blocks, the copolymers exhibit amphiphilicity and thermally induced aggregation behavior in aqueous solutions. The present work shows that block copolymer architecture is not necessary to achieve an amphiphilic character in PPO and PEG-based polymers. Instead a simple molecular tweaking by adding a very short hydrophilic or hydrophobic side-chain allows for attaining amphiphilicity and consequential thermoresponsiveness in PEG and PPO-rich polymers.

DFT studies of the drug carrier of anti-migraine (sumatriptan) on nano-graphene oxide (NGO) and graphene oxide/polyethylene glycol polymer nano-composite

Migraine headaches are one of the most serious disorders. Sumatriptan, the selective agonist of the 5-HT1B/D receptor, is the first choice for the treatment of migraine attacks that its oral bioavailability is less than 15%. The aim is to prepare and evaluate a new soluble oral film formulation of sumatriptan for the rapid treatment of migraine attacks and cluster headaches.In this study, simulated and evaluated a fast-dissolving film from sumatriptan by nano-graphene oxide (NGO) and its composite with polyethylene glycol polymer (NGO/PEG). After simulating and optimizing the structure of the NGO and its polymeric composite, it was used for loading the sumatriptan drug and was investigating the best conditions for achieving maximum amount and efficiency of drug loading.According to the structure of the NGO, there are three probabilities of interaction with the drug; the carboxyl group has more dipole moment (DM = 3.88D), more negative Gibbs energy (−5126.40 a.u.) and more entropy (1239.47 J·K−1·mol−1), so it shows a greater tendency to interact with polymer and drug. The secondary amine on sumatriptan (I-C) is more inclined to interact with the nano-surface of NGO and NGO/PEG. The results show, the composition of NGO/PEG has in more favorable structural and thermodynamic properties and drug absorption and release were better than NGO surface. The structural polarization of drug interaction with the nano-composite is more than the nano-graphene oxide (DMNGO@Sumatriptan = 3.31D and DMNGO/PEG@Sumatriptan = 9.62D). In totality, the properties of NGO and NGO/PEG nano-particles including easy synthesis and low-cost, low toxicity, unique shape, and geometry, ability to load biomaterials high, causes improve loading, release, and orientation of drug.

NMR Study of Polymer Diffusion in the Presence of a Biological Intracellular Crowder

Protein interactions take place in the crowded and heterogeneous intracellular milieu with macromolecular concentrations up to 400 mg/ml. The role of excluded-volume effects and soft non-specific interactions in macromolecular crowding has been traditionally studied in artificial crowders like Ficoll and dextran. Our measurements of flow properties show, however, that artificial crowders such as Ficoll have starkly different rheological characteristics from a complex biological crowder, bacterial cell lysate, at comparable concentrations. Moreover, biological crowders are a heterogeneous collection of biomolecules with a distribution of sizes, shapes and charge; these differences likely also affect translational diffusion of biomolecules within the cell. In this study, we examine the effects of size distribution and charge of a complex biological crowder on the diffusion of polymers and ask if this is similar to what is seen for artificial crowders like Ficoll. To answer this question, we use a top-down experiment using bacterial cell lysate as the crowder. To test the dynamical properties of polymer in the lysate environment, we measure the translational diffusion of the test polymer polyethylene glycol (PEG) using diffusion NMR. While PEG is not a biomolecule, it is a useful analog for a disordered protein. Our rheological tests show that while Ficoll is nearly Newtonian even at high concentrations, bacterial cell lysate is markedly viscoelastic. Results will provide a better understanding of the effects of complex biological crowders on polymer diffusion.

Study of curcumin partitioning in polymer-salt aqueous two phase systems

Curcumin is a polyphenolic compound derived from Curcuma longa, which has a wide range of pharmacological applications and it constitutes 2–5% of turmeric. An efficient separation method is needed for the purification of curcumin. A polymer-salt aqueous two-phase system (ATPS) has been developed for curcumin separation. The applied polymers include polyethylene glycol (PEG) 6000 and 2000, polypropylene glycol (PPG) 400 and a three-block copolymer of PEG-PPG (Pluronic L35), as well as magnesium sulfate and sodium sulfate. The phase behavior of the ATPSs and curcumin partitioning as well as the effect of cation, PEG molecular weight, polymer type and temperature (5, 15 and 25 °C) have been investigated. According to obtained results, Na2SO4 due to its high salting out effect is more suitable for the partitioning of curcumin. By increasing the molecular weight of the polymer, the hydrophobicity of the top phase and consequently, the partitioning increases. The partitioning of curcumin in the determined optimum PEG-salt (PEG6000-Na2SO4) and PPG-sodium sulfate ATPSs have been obtained 67 and 25, respectively. The lower volume ratio of the phases decreases the partitioning ability of PPG400-Na2SO4 ATPS. Pluronic L35-Na2SO4 was able to reach the complete partitioning of curcumin. As predicted by the calculated differences in solubility parameter applying group contribution method, this system has the most partition ability due to self-aggregation in aqueous solutions and by decreasing the temperature, the partition coefficient decreased, but it was still more than the other polymers.

Riboflavin-Targeted Drug Delivery.

Active targeting can improve the retention of drugs and drug delivery systems in tumors, thereby enhancing their therapeutic efficacy. In this context, vitamin receptors that are overexpressed in many cancers are promising targets. In the last decade, attention and research were mainly centered on vitamin B9 (folate) targeting; however, the focus is slowly shifting towards vitamin B2 (riboflavin). Interestingly, while the riboflavin carrier protein was discovered in the 1960s, the three riboflavin transporters (RFVT 1-3) were only identified recently. It has been shown that riboflavin transporters and the riboflavin carrier protein are overexpressed in many tumor types, tumor stem cells, and the tumor neovasculature. Furthermore, a clinical study has demonstrated that tumor cells exhibit increased riboflavin metabolism as compared to normal cells. Moreover, riboflavin and its derivatives have been conjugated to ultrasmall iron oxide nanoparticles, polyethylene glycol polymers, dendrimers, and liposomes. These conjugates have shown a high affinity towards tumors in preclinical studies. This review article summarizes knowledge on RFVT expression in healthy and pathological tissues, discusses riboflavin internalization pathways, and provides an overview of RF-targeted diagnostics and therapeutics.

Enteric pH responsive cargo release from PDA and PEG coated mesoporous silica nanoparticles: a comparative study in Drosophila melanogaster.

Physiological stimulus-specific cargo release from nanoparticle carriers is a holy grail of drug delivery research. While the majority of such work is carried out in vitro with cell lines, widespread use of common mammalian model systems – mice and rats – is difficult due to the associated cost and regulatory restrictions. Here we use the inexpensive, easily reared, excellent genetic model system Drosophila melanogaster to test pH responsive cargo release from widely used mesoporous silica nanoparticles (MSNs) coated with pH sensitive polydopamine (PDA) and polyethylene glycol (PEG) polymers. We synthesized 650 ± 75 nm diameter PDA or PEG coated mesoporous silica nanoparticles loaded with a fluorescent dye and fed to individual adult flies. Subsequently, the passage of the particles were monitored through the fly gut. As in mammals, the fly intestine has multiple pH specific zones that are easily accessible for imaging and also genetic, biochemical or physiological manipulations. We observed that both the species of MSNs ruptured around the acidic (pH < 4.0) middle midgut of the flies. PEG coated particles showed sharper specificity of release in the acidic middle midgut of flies than the PDA coated ones and had less tendency to clump together. Our results clearly show that the Drosophila gut can be used as a model to test pH responsive biocompatible materials in vivo. Our work paves the way for greater use of Drosophila as an in vivo complete systemic model in drug delivery and smart materials research. It also suggests that such specific delivery of chemical/biological cargo can be exploited to study basic biology of the gut cells and their communication with other organs.

Do Polymer Coatings Change the Aberrations of Conventional and Wavefront-guided Scleral Lenses?

The findings of this study indicate that patients could simultaneously be offered the individualized optical correction of wavefront-guided (WFG) lenses and the superior comfort afforded by polymer coatings. This could be helpful to patients with ectasia suffering ocular dryness or dependent on scleral lenses for lengthy periods of wear. Wavefront-guided scleral lenses target lower- and higher-order aberrations of individual eyes using submicrometer-level contours in the anterior lens surface. Hydrophilic polyethylene glycol (PEG) polymer coatings applied to lens surfaces improve comfort and wettability. This study aimed to quantify aberration changes (e.g., masking) when applying polymer coatings to WFG and conventional scleral lenses. Two control lenses (remained uncoated) and 14 experimental lenses (two repeated builds of seven aberration designs: one spherical, two coma, four full WFG [second- to fifth-order aberrations]) were manufactured, and aberrations were measured (mean of three) by two operators before and after coating. Root mean square (RMS) and visual image quality (logVSX) differences were calculated for 6-mm diameters. Median RMS aberration change due to coating was 0.012 μm (range, 0.008 to 0.057 μm). Maximum logVSX change due to coating was 0.073, predicting an approximately one letter change in acuity. Instrument sensitivity was 0.002 μm. Acute instrument and operator variabilities (standard deviations of individual [second- to fifth-order Zernikes] were all <0.027 μm). Longitudinal variability (control lenses) was low: all less than 0.017 μm. Although RMS of differences between repeated builds of all lenses was less than 0.25 D and not statistically significant, relatively, manufacture constituted the major variability, and RMS difference between repeated builds was at least four times greater than the effect of coating (median, 0.167 μm; range, 0.088 to 0.312 μm). Application of polymer coatings caused measurable changes in aberrations of WFG and conventional scleral lenses; however, these were clinically and statistically insignificant and within variability of repeated lens manufacture. In their current states, WFG lenses and polymer coatings could be used simultaneously.

Self-Assembling Scaffolds Supported Long-Term Growth of Human Primed Embryonic Stem Cells and Upregulated Core and Naïve Pluripotent Markers.

The maintenance and expansion of human embryonic stem cells (ESCs) in two-dimensional (2-D) culture is technically challenging, requiring routine manipulation and passaging. We developed three-dimensional (3-D) scaffolds to mimic the in vivo microenvironment for stem cell proliferation. The scaffolds were made of two 8-arm polyethylene glycol (PEG) polymers functionalized with thiol (PEG-8-SH) and acrylate (PEG-8-Acr) end groups, which self-assembled via a Michael addition reaction. When primed ESCs (H9 cells) were mixed with PEG polymers, they were encapsulated and grew for an extended period, while maintaining their viability, self-renewal, and differentiation potential both in vitro and in vivo. Three-dimensional (3-D) self-assembling scaffold-grown cells displayed an upregulation of core pluripotency genes, OCT4, NANOG, and SOX2. In addition, the expression of primed markers decreased, while the expression of naïve markers substantially increased. Interestingly, the expression of mechanosensitive genes, YAP and TAZ, was also upregulated. YAP inhibition by Verteporfin abrogated the increased expression of YAP/TAZ as well as core and naïve pluripotent markers. Evidently, the 3-D culture conditions induced the upregulation of makers associated with a naïve state of pluripotency in the primed cells. Overall, our 3-D culture system supported the expansion of a homogenous population of ESCs and should be helpful in advancing their use for cell therapy and regenerative medicine.

Bacterial Cellulose and Emulsified AESO Biocomposites as an Ecological Alternative to Leather.

This research investigated the development of bio-based composites comprising bacterial cellulose (BC), as obtained by static culture, and acrylated epoxidized soybean oil (AESO) as an alternative to leather. AESO was first emulsified; polyethylene glycol (PEG), polydimethylsiloxane (PDMS) and perfluorocarbon-based polymers were also added to the AESO emulsion, with the mixtures being diffused into the BC 3D nanofibrillar matrix by an exhaustion process. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy analysis demonstrated that the tested polymers penetrated well and uniformly into the bulk of the BC matrix. The obtained composites were hydrophobic and thermally stable up to 200 °C. Regarding their mechanical properties, the addition of different polymers lead to a decrease in the tensile strength and an increase in the elongation at break, overall presenting satisfactory performance as a potential alternative to leather.

Preparation of Polyethylene Glycol-Ginsenoside Rh1 and Rh2 Conjugates and Their Efficacy against Lung Cancer and Inflammation.

Low solubility and tumor-targeted delivery of ginsenosides to avoid off-target cytotoxicity are challenges for clinical trials. In the present study, we report on a methodology for the synthesis of polyethylene glycol (PEG)-ginsenoside conjugates through a hydrolysable ester bond using the hydrophilic polymer polyethylene glycol with the hydrophobic ginsenosides Rh1 and Rh2 to enhance water solubility and passive targeted delivery. The resulting conjugates were characterized by 1H nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FT-IR). 1H NMR revealed that the C-6 and C-3 sugar hydroxyl groups of Rh1 and Rh2 were esterified. The conjugates showed spherical shapes that were monitored by field-emission transmission electron microscopy (FE-TEM), and the average sizes of the particles were 62 ± 5.72 nm and 134 ± 8.75 nm for PEG-Rh1and PEG-Rh2, respectively (measured using a particle size analyzer). Owing to the hydrophilic enhancing properties of PEG, PEG-Rh1 and PEG-Rh2 solubility was greatly enhanced compared to Rh1 and Rh2 alone. The release rates of Rh1 and Rh2 were increased in lower pH conditions (pH 5.0), that for pathophysiological sites as well as for intracellular endosomes and lysosomes, compared to normal-cell pH conditions (pH 7.4). In vitro cytotoxicity assays showed that the PEG-Rh1conjugates had greater anticancer activity in a human non-small cell lung cancer cell line (A549) compared to Rh1 alone, whereas PEG-Rh2 showed lower cytotoxicity in lung cancer cells. On the other hand, both PEG-Rh1 and PEG-Rh2 showed non-cytotoxicity in a nondiseased murine macrophage cell line (RAW 264.7) compared to free Rh1 and Rh2, but PEG-Rh2 exhibited increased efficacy against inflammation by greatly inhibiting nitric oxide production. Thus, the overall conclusion of our study is that PEG conjugation promotes the properties of Rh1 for anticancer and Rh2 for inflammation treatments. Depends on the disease models, they could be potential drug candidates for further studies.

Shaping of MOFs via freeze-casting method with hydrophilic polymers and their effect on textural properties

Abstract Shaping of metal-organic frameworks (MOFs) and tuning of their sorption properties is a very important and challenging aspect for the usage of MOFs for many applications. Both shaping and tuning can be addressed by composite preparation as an effective method. Herein, we present the shaping of the hydrothermally stable MOFs aluminum fumarate, MIL-160(Al) and MIL-101(Cr) using the freeze-casting method with the hydrophilic polymer binders polyacrylic acid (PAA), sodium polyacrylate (PAANa), polyethylene glycol (PEG), polyethylene imine (PEI), polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP). Furthermore, the effect of in-situ cross-linking below the freezing point (cryopolymerization) on the textural properties of monoliths was also investigated using MIL-101(Cr) and aluminum fumarate with the polymer PVA. The selected MOFs were chosen due to their outstanding stability, sorption properties and differing hydrophilicities. In the obtained mechanically stable monoliths, each MOF showed a different compatibility with the used polymers. From 21 different MOF@polymer composites with 80 wt% loading of MOF, 12 of them exhibited negligible pore blocking effects and very high nitrogen sorption properties in correspondence with the MOF mass fraction. On the other hand, water uptake is especially in cases of MOF@PVA and MOF@PVP in good agreement with the MOF fraction and can be enhanced by the contribution of the hydrophilic polymer to the composite. In particular, most MIL-101(Cr) composites showed a hydrophilic shift to lower relative pressure p·p0−1 compared to the rather hydrophobic neat MIL-101(Cr). IR spectroscopy indicated a clear interaction of PEI with the Al-MOFs aluminum fumarate and MIL-160(Al) resulting in MOF pore blocking. The molecular weight of the polymer is not significant for the freeze-casting method but plays an important role in the cryopolymerization.

Functionally modified magnetic nanoparticles for effective siRNA delivery to prostate cancer cells in vitro.

Different types of siRNA delivery vehicles including nanoparticles have been synthesized and utilized for prostate cancer gene therapy. However, one of the most common limitations being faced is the toxicity of cationic polymers toward the cells. In the current study, magnetic nanoparticles were prepared and conjugated with cationic polymer, polyethylenimine. Then polyethylene glycol was conjugated with polyethylenimine to improve the biocompatibility of nanoparticles. The transmission electron microscopy size of nanoparticles was found to be 15.82 (±9.07) nm, while hydrodynamic size was about 79.20 (±0.68) nm. Zeta potential analysis of polyethylenimine and polyethylene glycol-coated nanoparticles was +31.4 (±0.62) and +5.65 (±0.76) mV, respectively. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance confirmed the presence of polyethylene glycol and polyethylenimine polymers in magnetic nanoparticles. Cell viability test in mouse fibroblast NIH 3T3 and prostate cancer PC3 cells showed an increased in biocompatibility of functionally modified polyethylene glycol–polyethylenimine–Fe3O4 nanoparticles. siRNA targeting a disintegrin and metalloproteinase 10 (ADAM10) was successfully loaded into the polyethylene glycol–polyethylenimine–Fe3O4 nanoparticles and delivered to PC3 cells. The results clearly demonstrated a significant decrease in cell viability, which increased within a certain siRNA concentration. The inhibitory concentration (IC50) value for ADAM10 siRNA was calculated to be 15.83 nM after 72 h. Confocal microscopy confirmed the delivery of siRNA-loaded nanoparticles intracellularly to the tumor cells cytosol. This magnetic system can be used as a powerful platform to inhibit cancer cells progression.

Nonequilibrium Reshaping of Polymersomes via Polymer Addition.

Polymersomes are a class of artificial liposomes, assembled from amphiphilic synthetic block copolymers, holding great promise toward applications in nanomedicine. The diversity in polymersome morphological shapes and, in particular, the precise control of these shapes, which is an important aspect in drug delivery studies, remains a great challenge. This is due to a lack of general methodologies that can be applied and the inability to capture the morphologies at the nanometer scale. Here, we present a methodology that can accurately control the shape of polymersomes via the addition of polyethylene glycol (PEG) under nonequilibrium conditions. Various shapes including spheres, ellipsoids, tubes, discs, stomatocytes, nests, stomatocyte-in-stomatocytes, disc-in-discs, and large compound vesicles (LCVs) can be uniformly captured by adjusting the water content and the PEG concentration. Moreover, these shapes undergo nonequilibrium changes in time, which is reflected in their phase diagram changes. This research provides a universal tool to fabricate all shapes of polymersomes by controlling three variables: water content, PEG concentration, and time. The use of the biofriendly polymer PEG enables the application of this methodology in the field of nanomedicine.

Applications of Sustainable Polymer-Based Phase Change Materials in Mortars Composed by Different Binders.

Eco-sustainable, low toxic and low flammable poly-ethylene glycol (PEG) was forced into flakes of the porous Lecce stone (LS), collected as stone cutting wastes, employing a very simple cheap method, to produce a “form-stable” phase change material (PCM). The experimental PCM was included in mortars based on different binders (hydraulic lime, gypsum and cement) in two compositions. The main thermal and mechanical characteristics of the produced mortars were evaluated in order to assess the effects due to the incorporation of the PEG-based PCM. The mortars containing the PEG-based PCM were found to be suitable as thermal energy storage systems, still displaying the characteristics melting and crystallization peaks of PEG polymer, even if the related enthalpies measured on the mortars were appreciably reduced respect to pure PEG. The general reduction in mechanical properties (in flexural and compressive mode) measured on all the mortars, brought about by the presence of PEG-based PCM, was overcome by producing mortars possessing a greater amount of binder. The proposed LS/PEG composite can be considered, therefore, as a promising PCM system for the different mortars analyzed, provided that an optimal composition is identified for each binder.

Exploration of sulfur in mixt anchor materials for lithium sulfur batteries

Lithium–sulfur (Li–S) batteries are drawing tremendous attention owing to high energy density, high theoretical capacity and high availability of sulfur. The practical application of Li–S batteries is retarded due to the dissolution of polysulfides and shuttle mechanism. With this backdrop, cyclic stability and Coulombic efficiency is demoted. In this regard, sulfur is loaded with three different materials such as metal oxide (MnO2) and carbon source of Acetylene Black (AB) and polymer Polyethylene glycol (PEG) which can be used as an electrode for Li–S batteries. The structural and morphological behavior has been analyzed by x-ray diffraction, Raman analysis and scanning electron microscopy. S/MnO2 composite delivers a discharge capacity of 1030 mAh g−1 in its initial cycle. S/MnO2 composite has a strong ability to adsorb the lithium polysulfides escalating the Coulombic efficiency.