Polyethylene Glycol Polymers Research Articles

Magnetic boron nitride nanosheets-based on pH-responsive smart nanocarriers for the delivery of doxorubicin for liver cancer treatment

A new drug delivery system (DDS) type complexing magnetic nanoparticles (MNP) along with boron nanosheets (BNN) coated with a pH-responsive polymer-polyethylene glycol (PEG) for the manageable loading/release of the anti-cancerous drug, doxorubicin (DOX), was created (MNP-BNN-PEG-DOX). The X-ray diffraction patterns of the nanocomposites displayed wide diffraction peaks for BNN at 25.1° and 42.3°, belonging to the (002) and (100) planes, correspondingly. Additionally, the characteristic peaks of Fe3O4 appeared at 30.5°, 35.9°, 43.6°, 54.1°, 57.5°, and 63.2°, belonging to the (220), (311), (400), (422), (511), and (440) crystal planes, correspondingly. Moreover, the magnetic properties of the nanocomposites revealed that the MNP-BNN remained magnetic after coating with PEG. The saturation magnetization (Ms) of the uncoated-MNP-BNN and MNP-BNN-PEG-1 were 49.4 and 42.3 emu g−1, respectively. Both in vitro and in vivo analyses shown that DDS might inhibit tumor growth, provoke cancer cell apoptosis, and reduce the cytotoxic effects of DOX. In vivo analysis demonstrated that after treatment with phosphate-buffered saline (PBS), MNP-BNN-PEG-1, free DOX, and MNP-BNN-PEG-1-DOX, the average tumor growth and weight were 1906, 1997, 1188, and 1043 nm and 0.17, 0.20, 0.13, and 0.07 g, respectively. The MNP-BNN-PEG-DOX nanoparticles could be an effective treatment and potential alternative for liver cancer therapy.

MODIFICATION NANO-SIZE OF ZINC OXIDE (ZnO-NS) WITH POLYETHYLENE GLYCOL AND APPLICATION AS ANTIMICROBIAL

Sol-gel is a simple method used to synthesize nano-size ZnO (ZnO-NS) in many applications. It acts as an antimicrobial agent for Escherichia coli and Aspergillus niger infections. The nano-size and patterned nanorods structure of ZnO enhances anti-microbial properties. This study used Polyethylene Glycol (PEG-6000) polymer compounds with variations in their 3, 5, and 10% compositions as templates for the formation of the nanorods. The morphology of the ZnO-NS produced determined the increase in anti-microbial activity. Furthermore, those generated from 5% PEG composition (ZnO/PEG-5) have the smallest size with the greatest anti-microbial activity on inhibition zones against E. coli and A. niger, each of 8.5-10.5 mm. There are morphological differences in each variable in the homogeneity distribution level of the spherical and rod dimension patterns of ZnO-NS. This is based on characterization with UV-VIS-DRS and Fourier-Transform infrared (FT-IR) for the analysis of Zn-O interactions at wave number 500-550 cm-1. Field Emission Scanning Electron Microscopy-Dispersive Scanning Electron Microscope (FE-SEM) and Energy dispersive X-ray spectroscopy (EDX) was used for dimensional pattern analysis, while X-ray diffraction (XRD) was applied for hexagonal wurtzite ZnO structures following the ICSD-65122 standard.

Fabrication of curcumin-loaded magnetic PEGylated-PLGA nanocarriers tagged with GRGDS peptide for improving anticancer activity

Carrier-mediated drug delivery systems are highly promising as a treatment option for the targeted delivery of potent cytotoxic drugs with increased efficacy and safety. Considering that poly (lactic-co-glycolic acid) (PLGA) and polyethylene glycol (PEG) polymers each provide certain advantages for biological purposes, PEGylated-PLGA nanoparticles have emerged as a leading candidate among other alternatives. Furthermore, these nanoparticles can be modified with the specific short peptide sequences such as glycine-arginine-glycine-aspartic acid‑serine (GRGDS), which selectively binds to integrins overexpressed in most cancer cells, allowing for targeted delivery. Here, we reported the details in fabrication and characterization of magnetic PEGylated-PLGA nanoparticles functionalized with GRGDS peptide. In addition, superparamagnetic iron oxide nanoparticles (SPIONs) and the natural pharmaceutical compound curcumin (Cur) were loaded into these polymeric nanoparticles to assess their anticancer activity potential. Overall, this study provides comprehensive methodologies, including all synthesis procedures, challenges, and useful suggestions for peptide-conjugated polymeric nanoparticles that may be used for cellular targeting and therapeutic applications.•Step by step fabrication protocol for the Cur loaded magnetic PEGylated-PLGA nanoparticles was presented.•Validation of the fabrication and the GRGDS conjugation to the nanoparticles were shown via detailed characterization studies.•The cytotoxic effect of the Cur-loaded and GRGDS-tagged magnetic nanoparticles was tested on T98G glioblastoma cell line as a preliminary in vitro study.

Amine-assisted catechol-based nanocoating on ultrasmall iron oxide nanoparticles for high-resolution T1 angiography.

Surface engineered iron oxide nanoparticles (IONPs) with catecholic ligands have been investigated as alternative T1 contrast agents. However, complex oxidative chemistry of catechol during IONP ligand exchange causes surface etching, heterogeneous hydrodynamic size distribution, and low colloidal stability because of Fe3+ mediated ligand oxidation. Herein, we report highly stable and compact (∼10 nm) Fe3+ rich ultrasmall IONPs functionalized with a multidentate catechol-based polyethylene glycol polymer ligand through amine-assisted catecholic nanocoating. The IONPs exhibit excellent stability over a broad range of pHs and low nonspecific binding in vitro. We also demonstrate that the resultant NPs have a long circulation time (∼80 min), enabling high resolution T1 magnetic resonance angiography in vivo. These results suggest that the amine assisted catechol-based nanocoating opens a new potential of metal oxide NPs to take a step forward in exquisite bio-application fields.

Synthesis and characterization of PES/PSF/PEG by immersion precipitation for Mediterranean seawater desalination by FO membrane

AbstractIn the present study, a simple, inexpensive, nontoxic, and environmentally friendly polyethylene glycol (PEG) polymer was used to enhance the hydrophilicity of the forward osmosis (FO) membrane using various PEG concentrations as a pore forming agent in the casting solution of polyethersulfone/polysulfone (PES/PSF) blend membranes. A nonwoven PES/PSF FO blend membrane was fabricated via the immersion precipitation phase inversion technique. The membrane dope solution was cast on polyethylene terephthalate (PET) nonwoven fabric. The results revealed that PEG is a pore forming agent and that adding PEG promotes membrane hydrophilicity. The membrane with 1 wt% PEG (PEG1) had about 27% lower contact angle than the pristine blend membrane. The PEG1 membrane has less tortuosity (which reduces from 3.4–2.73), resulting in a smaller structure parameter (S value) of 277 μm, due to the presence of open pores on the bottom surface structure, which results in diminished ICP. Using 1 M NaCl as the draw solution and distilled water as the feed solution, the PEG1 membrane exhibited higher water flux (136 L m−2 h−1) and lower reverse salt flux (1.94 g m−2 h−1). Also, the selectivity of the membrane, specific reverse salt flux, (Js/Jw) showed lower values (0.014 g/L). Actually, the PEG1 membrane has a 34.6% higher water flux than the commercial nonwoven‐cellulose triacetate (NW‐CTA) membrane. By means of varied concentrations of NaCl salt solution (0.6, 1, 1.5, and 2 M), the membrane with 1 wt% PEG showed improved FO separation performance with permeate water fluxes of 108, 136, 142, and 163 L m−2 h−1. In this work, we extend a promising gate for designing fast water flux PES/PSF/PEG FO blend membranes for water desalination.

Tie-Line Analysis Reveals Interactions Driving Heteromolecular Condensate Formation

Phase separation of biomolecules gives rise to membraneless organelles that contribute to the spatiotemporal organization of the cell. In most cases, such biomolecular condensates contain multiple components, but the manner in which interactions between components control the stability of condensates have remained challenging to elucidate. Here, we develop an approach to determine tie-line gradients in ternary biomolecular phase-separation systems based on measurements of the dilute phase concentration of only one component. We show that the sign of the tie-line gradient is related to the cross-interaction energy between the polymers in the system and discriminates between associative and segregative phase separation. Using this approach, we study the interaction between protein fused in sarcoma (FUS) and polyethylene glycol (PEG) polymer chains and measure positive tie-line gradients. Our results show that PEG drives phase separation through an associative interaction with FUS, other than through acting as an inert crowder. We further study the interaction between poly(A) ribonucleic acid (RNA) (3.0±0.5 kDa [kilodalton]) and the protein G3BP1, and using the tie-line gradient as a reporter for the stoichiometry of polymers in the condensate, we determine a G3BP1-to-poly(A) RNA molar ratio of 1∶4 in the dense phase. Our framework for measuring tie-line gradients opens up a route for the characterization of interaction types and compositions in ternary phase-separation systems.Received 31 May 2022Revised 24 October 2022Accepted 1 December 2022DOI:https://doi.org/10.1103/PhysRevX.12.041038Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasLiquid-liquid phase transitionProtein-protein interactionsTechniquesConfocal imagingBiological Physics

Nanofluids stability on amino-silane and polymers coating titanium dioxide and zinc oxide nanoparticles

The nanofluids technology keeps advancing in the recent decades despite the modus operandi in formulating stable nanofluids is still in the grey area. This paper provides a further understanding of the nanoparticles and nanofluids synthesis methods with surface modification alternative in contemplation of nanofluid stability enhancement. Due to the shortcomings of this technology, which is the dispersity and stability issue owing to the van Der Waals attraction, this paper reports a full formulation design guideline in term of the temperature, crystal growth duration, nanoparticles concentration, pH and nanofluids synthesis method to obtain the stable titanium dioxide (TiO2) and zinc oxide (Zn0) nanofluids. Compatibility of polymers polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP) and an amino-silane; (3-Aminopropyl) triethoxysilane (APTES) with the synthesized nanoparticles were observed. Our findings discovered that the compatible polymer-nanoparticle composites are TiO2-PVP and ZnO-PEG with zeta potential values at 47.2 mV and 56.5 mV respectively.

HA-PEG-PCL Nanoparticles With Paclitaxel Loaded For Targeted Delivery To Colon Cancer

For improved treatment efficacy with no or few adverse effects and higher patient compliance, novel delivery techniques with selective dispersion are required. The biodegradable and biocompatible polymers hyaluronic acid (HA), polyethylene glycol (PEG), and polycaprolactone (PCL) were used to create paclitaxel-loaded nanoparticles. The development and characterisation of a Paclitaxel-loaded HA-PEG-PCL polymeric nanoparticulate drug delivery system were the goals of the current study work in order to increase the therapeutic efficacy and targeted Paclitaxel distribution. The copolymers were chemically created, and IR spectroscopies were used to identify them. Transmission electron microscopy, particle size, percentage of drug entrapment, cell viability studies, stability, and in vitro drug release profile were used to describe the nanoparticles' structure and morphology. To determine whether PTX was crystalline or amorphous inside the polymer matrix, experiments using differential scanning calorimetry and X-ray diffraction were also carried out. Zeta potentials for blank NPs and PTX-HA-PEG-PCL NPs were respectively -15.4±1.23 mV and -18±2.35 mV. In 144 hours, PTX-HA-PEG-PCL NPs demonstrated a 58.08±3.8 release of PTX at pH 7.4. Because HA functions as a ligand for the CD44 receptors that are over expressed on HT-29 cells, the PTX-HA-PEG-PCL NPs demonstrated noticeably more cytotoxicity as a result of better formulation internalization. The proposed nanotechnology’s-controlled drug release behavior showed its potential for colon cancer cell lines

All-Aqueous Bicontinuous Structured Liquid Crystal Emulsion through Intraphase Trapping of Cellulose Nanoparticles.

Here, we describe the all-aqueous bicontinuous emulsions with cholesteric liquid crystal domains through hierarchical colloidal self-assembly of nanoparticles. This is achieved by homogenization of a rod-like cellulose nanocrystal (CNC) with two immiscible, phase separating polyethylene glycol (PEG) and dextran polymer solutions. The dispersed CNCs exhibit unequal affinity for the binary polymer mixtures that depends on the balance of osmotic and chemical potential between the two phases. Once at the critical concentration, CNC particles are constrained within one component of the polymer phases and self-assemble into a cholesteric organization. The obtained liquid crystal emulsion demonstrates a confined three-dimensional percolating bicontinuous network with cholesteric self-assembly of CNC within the PEG phase; meanwhile, the nanoparticles in the dextran phase remain isotropic instead. Our results provide an alternative way to arrest bicontinuous structures through intraphase trapping and assembling of nanoparticles, which is a viable and flexible route to extend for a wide range of colloidal systems.

Development of high reusability trifunctional polyethersulfones microspheres for the removal of methyl orange

This study focused on the synthesis of trifunctional microspheres with adsorption, degradation, and magnetic responsive properties. Firstly, polyethersulfones (PES) encapsulated poly(diallyldimethyl ammonia) chloride (PDDA) functionalized iron oxide (Fe3O4) microspheres were produced via phase inversion method. The PDDA/Fe3O4-PES microspheres were further coated with Fe3O4 nanoparticles (NPs) on the surface to provide the degradation ability to the formed c-PDDA/Fe3O4-PES microspheres. Characterization results such as FTIR analysis confirmed the coating of PDDA on Fe3O4 NPs, while the TGA analysis proved the excellent thermal stability of microspheres after the incorporation of PDDA/Fe3O4 NPs. BET specific surface area of microspheres was measured at 13.90 m2/g. Besides, the pH drift method confirmed the presence of positive charge on microspheres surface, which is important for the removal of anionic pollutants. Moreover, porous structure of microspheres was also observed under SEM. Formulation study was also carried out to investigate the suitable concentration for the synthesis of microspheres, including the concentration of PES polymer (1–20 wt%), the loading of PDDA/Fe3O4 NPs (1–5 wt%), and the concentration of polyethylene glycol (PEG) (1–20 wt%). The microspheres synthesized from different formulations were subjected to the batch removal of methyl orange (MO). Results showed that a 72.53 % removal of MO can be obtained under the following microspheres synthesis formulations: 10wt% of PES polymer, 2 wt% of PDDA/Fe3O4 NPs, and 5 wt% of PEG polymer. Lastly, the c-PDDA/Fe3O4-PES microspheres also demonstrated an excellent reusability as compared to pure PES microspheres. The c-PDDA/Fe3O4-PES microspheres could be reused up to 5 cycles without the need of regeneration while still maintaining high MO removal efficiency.

Cationization of organic molecules under keV and MeV primary ion bombardment

The present work reports on cationization characteristics of organic molecules in alkali metal environment. Samples of arginine and polyethylene glycol polymers with average masses of 600, 1000 and 1500 were mixed with sodium- and potassium trifluoroacetate of various concentrations, and analyzed through secondary ion mass spectrometry. Bombardment proceeded with ions within both keV and MeV energy domains. Added salts positively affected the secondary ion yield through attachment of Na or K to organic molecule. Ionization differences between swift (MeV) ions and cluster ions, commonly used for secondary ion mass spectrometry analysis, were studied for arginine and PEG 600. While for arginine, secondary ion yield enhancement was only by a factor of 2, when analysing with MeV ions, and no enhancement was observed with keV Bi3 clusters, all polyethylene glycol samples showed increase of the secondary ion yield by factors between 3 and 40, depending on the amount of potassium or sodium that was mixed into the matrix. Additionally, higher amounts of salts also resulted in decreased fragmentation probability for organic molecules, reducing the intensities of specific fragments by more than two orders of magnitude.

Enabling Solution Processable COFs through Suppression of Precipitation during Solvothermal Synthesis.

Covalent organic frameworks (COFs) are crystalline, nanoporous materials of interest for various applications, but current COF synthetic routes lead to insoluble aggregates which precludes processing for practical implementation. Here, we report a COF synthesis method that produces a stable, homogeneous suspension of crystalline COF nanoparticles that enables the preparation of COF monoliths, membranes, and films using conventional solution-processing techniques. Our approach involves the use of a polar solvent, diacid catalyst, and slow reagent mixing procedure at elevated temperatures which altogether enable access to crystalline COF nanoparticle suspension that does not aggregate or precipitate when kept at elevated temperatures. On cooling, the suspension undergoes a thermoreversible gelation transition to produce crystalline and highly porous COF materials. We further show that the modified synthesis approach is compatible with various COF chemistries, including both large- and small-pore imine COFs, hydrazone-linked COFs, and COFs with rhombic and hexagonal topologies, and in each case, we demonstrate that the final product has excellent crystallinity and porosity. The final materials contain both micro- and macropores, and the total porosity can be tuned through variation of sample annealing. Dynamic light scattering measurements reveal the presence of COF nanoparticles that grow with time at room temperature, transitioning from a homogeneous suspension to a gel. Finally, we prepare imine COF membranes and measure their rejection of polyethylene glycol (PEG) polymers and oligomers, and these measurements exhibit size-dependent rejection and adsorption of PEG solutes. This work demonstrates a versatile processing strategy to create crystalline and porous COF materials using solution-processing techniques and will greatly advance the development of COFs for various applications.

Aqueous Supercapacitors with Low Cost and High Voltage Enabled by Co‐Solute Crowding Effect of Electrolyte

AbstractDeveloping high‐voltage and environmentally friendly aqueous electrolytes have become a significant trend in supercapacitors (SCs). However, achieving this goal usually requires the use of “water‐in‐salt” (WIS) electrolytes, inevitably increasing manufacturing costs and sometimes posing problems such as environmental pollution. Here, we developed a water/organic solvent hybrid electrolyte (8 m NaClO4‐20 % H2O‐30 % ACN‐50 % PEG‐200) with low cost and high‐voltage capacity using the water‐miscible polymer polyethylene glycol (PEG) as a crowding agent to suppress water activity, and acetonitrile (ACN) as a co‐solvent to improve the ion transport properties. The synergistic advantages of the two co‐solvents allow SCs using this electrolyte to have a high operative voltage window of up to 2.6 V, currently the highest operating voltage for aqueous carbon‐based SCs, excellent capacity retention (over 11000 cycles) and high energy densities (31.2 Wh kg−1). This work provides a promising method for developing green and inexpensive high‐voltage window aqueous electrolytes.

Markedly Reduced FVIII Recovery Associated with Anti-FVIII Peg Antibodies after BNT162b2 Sars-Cov-2 Vaccination

Background The covalent link of polyethylene glycol (PEG) chains to recombinant factor VIII (FVIII) molecule is one of the most established approaches to produce novel therapeutic FVIII products with extended half-life (EHL). To date, three PEGyated-FVIII molecules, rurioctocog alfa pegol, turoctocog alfa pegol, and damoctocog alfa pegol are available for treatment of hemophilia A patients. From the pivotal clinical studies data, they showed comparable safety profile and pharmacokinetic with a mean half-live 1.3-1.7 times longer than the standard non-PEGylated FVIII. Although the PEG polymer is considered non immunogenic, antibodies against PEG, called pre-existing anti-PEG antibodies (APAs), have been reported in persons never treated with PEGylated drugs owing to PEG exposure during the activities of daily living. These antibodies can impact the clinical efficacy of PEGylated drug therapies by accelerating the blood clearance and changing pharmacokinetic. Recently, small amounts of PEG are also included in the lipid nanoparticles of the mRNA SARS-Cov-2 vaccines, BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna). Aim To describe a poor plasma FVIII recovery after the first infusion of a PEGylated FVIII product in two male patients with severe hemophilia A without inhibitor at about one month from the second dose of the BNT162b2 SARS-Cov-2 vaccination. Method About two months after the first dose of the SARS-Cov-2 vaccine and one month after the second, before switching from a standard half-life to a PEGylated FVIII product, patients underwent a PK study by infusion of 50 IU/kg of turoctocog alfa pegol (patient 1) or damoctocog alfa pegol (patient 2). FVIII activity was measured by Chromogenix Coamatic FVIII (Werfen) in plasma samples collected before and after the PEGylated FVIII infusion. Anti-PEGylated FVIII antibodies were searched by means of a home-made ELISA in plasma samples collected before administration of SARS-Cov-2 vaccine and at PK study. The assay was performed by using as capturing substrates each of the licensed PEGylated FVIII product (rurioctocog alfa pegol, turoctocog alfa pegol, and damoctocog alfa). Moreover, a non-PEGylated standard FVIII (Advate®) was employed as control substrate. Results FVIII coagulant activity measured after the infusion of 50 IU/kg of the PEGylated FVIII product showed a very low plasma recovery, 5% for patient 1 and 4% for patient 2. Anti-PEGylated FVIII antibodies reacting with each PEGylated FVIII products were found in plasma samples collected at PK baseline and after FVIII infusion but not in a sample obtained before the SARS-Cov-2 vaccination. No reactivity was found in vitro against the non-PEGylated standard FVIII product (figure). Conclusions Our finding of antibodies reacting with the PEGylated part of the FVIII molecule induced or boosted by BNT162b2 SARS-Cov-2 vaccination supports the view that the administration of the mRNA vaccine could impair plasma FVIII recovery after infusion of a PEGylated product. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Development of a Workflow to Engineer Tailored Microparticles Via Inkjet Printing.

New drug development and delivery approaches result in an ever-increasing demand for tailored microparticles with defined sizes and structures. Inkjet printing technologies could be promising new processes to engineer particles with defined characteristics, as they are created to precisely deliver liquid droplets with high uniformity. D-mannitol was used as a model compound alone or co-processed with the pore former agent ammonium bicarbonate, and the polymer polyethylene glycol 200. Firstly, a drop shape analyzer was used to characterize and understand ink/substrate interactions, evaporation, and solidification kinetics. Consequently, the process was transferred to a laboratory-scale inkjet printer and the resulting particles collected, characterized and compared to others obtained via an industrial standard technique. The droplet shape analysis allowed to understand how 3D structures are formed and helped define the formulation and process parameters for inkjet printing. By adjusting the drop number and process waveform, spherical particles with a mean size of approximately 100µm were obtained. The addition of pore former and polymer allowed to tailor the crystallization kinetics, resulting in particles with a different surface (i.e., spike-like surface) and bulk (e.g. porous and non-porous) structure. The workflow described enabled the production of 3D structures via inkjet printing, demonstrating that this technique can be a promising approach to engineer microparticles.

Engineering and Validation of a Peptide-Stabilized Poly(lactic-co-glycolic) Acid Nanoparticle for Targeted Delivery of a Vascular Disruptive Agent in Cancer Therapy.

Developing a biocompatible and biodegradable nanoparticle (NP) carrier that integrates drug-loading capability, active targeting, and imaging modality is extremely challenging. Herein, we report an NP with a core of poly(lactic-co-glycolic) acid (PLGA) chemically modified with the drug combretastatin A4 (CA4), a vascular disrupting agent (VDA) in clinical development for ovarian cancer (OvCA) therapy. The NP is stabilized with a short arginine-glycine-aspartic acid-phenylalanine x3 (RGDFFF) peptide via self-assembly of the peptide on the PLGA surface. Importantly, the use of our RGDFFF coating replaces the commonly used polyethylene glycol (PEG) polymer that itself often induces an unwanted immunogenic response. In addition, the RGD motif of the peptide is well-known to preferentially bind to αvβ3 integrin that is implicated in tumor angiogenesis and is exploited as the NP's targeting component. The NP is enhanced with an optical imaging fluorophore label via chemical modification of the PLGA. The RGDFFF-CA4 NPs are synthesized using a nanoprecipitation method and are ∼75 ± 3.7 nm in diameter, where a peptide coating comprises a 2-3 nm outer layer. The NPs are serum stable for 72 h. In vitro studies using human umbilical cord vascular endothelial cells (HUVEC) confirmed the high uptake and biological activity of the RGDFFF-CA4 NP. NP uptake and viability reduction were demonstrated in OvCA cells grown in culture, and the NPs efficiently accumulated in tumors in a preclinical OvCA mouse model. The RGDFFF NP did not induce an inflammatory response when cultured with immune cells. Finally, the NP was efficiently taken up by patient-derived OvCA cells, suggesting a potential for future clinical applications.

Water soluble polymer biodegradation evaluation using standard and experimental methods

Multiple polyethylene glycol (PEG) polymers ranging in molecular weight (MW) from 4000 to 500,000 Da, polyvinyl alcohol (PVOH) polymers with degrees of hydrolysis (DH) of 79 % and 88 % and MW 10,000 to 130,000 Da, and carboxy methyl cellulose (CMC) polymers with degrees of substitution (DS) ranging from 0.6 to 1.2 were evaluated in standard screening biodegradation tests to assess method limitations, modification potential, and reproducibility. All PEGs and PVOHs mineralized completely in OECD 301B and 302B studies reaching >80 % biodegradation with negligible dissolved organic carbon remaining at study completion. For high MW PEOs, extension of test duration was needed to reach full extent of mineralization. CMC biodegradation was directly correlated to degree of substitution with CMC 0.6 biodegrading extensively, CMC 0.79 partially biodegrading, and CMC 1.2 not biodegrading significantly in OECD 301B and 302B studies. For all materials tested in both an OECD 301B and 302B, fewer days were necessary to reach 60 % biodegradation in the OECD 302B indicating increased rates of biodegradation with higher inoculum to test chemical ratios. In a series of investigative studies using respirometry as the analytical endpoint, significant variability in the presence of competent degraders in small volume grab samples of river water was observed. Research is needed to overcome this variability and develop a standardized reproducible test method to accurately assess polymer mineralization in river water. At study completion, residual dissolved organic carbon (DOC) data confirmed respirometry data, high levels of mineralization resulted in negligible residual DOC while low levels of mineralization resulted in significant residual DOC, up to dose concentrations. DOC measurements provided confirmation of complete biodegradation when biomass incorporation and test system set up resulted in variable carbon dioxide production or oxygen demand.

Enhancement of Electrochemical Stability Window and Electrical Properties of CNT-Based PVA–PEG Polymer Blend Composites

New polymer blend composite electrolytes (PBCEs) were prepared by the solution casting technique using poly(vinyl alcohol) (PVA)-polyethylene glycol (PEG), sodium nitrate (NaNO3) as a doping salt and multiwalled carbon nanotubes (MWCNTs) as fillers. The X-ray diffraction pattern confirms the structural properties of the polymer blend composite films. FTIR investigations were carried out to understand the chemical properties and their band assignments. The ionic conductivity of the 10 wt % MWCNTs incorporated PVA-PEG polymer blend was measured as 4.32 × 10-6 S cm-1 at 20 °C and increased to 2.253 × 10-4 S/cm at 100 °C. The dependence of its conductivity on temperature suggests Arrhenius behavior. The equivalent circuit models that represent the R s(Q1(R1(Q2(R2(CR3))))) were used to interpret EIS data. The dielectric behavior of the samples was investigated by utilizing their AC conductance spectra, dielectric permittivity, dielectric constant (εi and εr), electric modulus (Mi and Mr), and loss tangent tan δ. The dielectric permittivity of the samples increases due to electrode polarization effects in low frequency region. The loss tangent's maxima shift with increasing temperature; hence, the peak height rises in the high frequency region. MWCNTs-based polymer blend composite electrolytes show an enhanced electrochemical stability window (4.0 V), better transference number (0.968), and improved ionic conductivity for use in energy storage device applications.

Enhanced pervaporation performance of PEG membranes with synergistic effect of cross-linked PEG and porous MOF-508a

MOF-508a with moderate 1D channels and large pore cavity size, was successfully synthesized and firstly incorporated into polyethylene glycol (PEG) to prepare mixed matrix membranes (MMMs) for desulfurization via pervaporation. Four kinds of cross-linkers were employed to cure PEG polymers, and PEG membrane cured with oxalic acid acquired much better comprehensive pervaporation performance. The uniformly dispersed MOF-508a in PEG matrix interrupted the crystalline region and decreased PEG crystallization degree. MOF-508a might act as facilitated transport carriers for thiophene molecules based on coordination interaction between Zn2+ and S, and large pore cavities provided multi-scale transport pathways for thiophene molecules. Besides, the strong interaction between MOF-508a and PEG enhanced the interfacial compatibility, which might provide more selective transport pathways for small molecules. Owing to the synergistic effect of cross-linked PEG and porous MOF-508a, the MOF-508a/PEG-5 MMMs exhibited outstanding enrichment factor of 30.4 with permeation flux of 0.485 kg/m2h, which were 98 % and 110 % higher than those of pristine PEG membrane. The enrichment factor of MOF-508a/PEG out-performed most the ever-reported membranes, which might provide some new insight in designing high-performance MMMs by rationally achieving synergy of porous fillers and polymer matrix.

Rationalizing the Effect of Polymer-Controlled Growth of Perovskite Single Crystals on Optoelectronic Properties.

To improve and modulate the optoelectronic properties of single-crystal (SC) metal halide perovskites (MHPs), significant progress has been achieved. Polymer-assisted techniques are a great approach to control the growth rate of SCs effectively. However, the resultant optoelectrical properties induced by polymers are ambiguous and need to be taken into the consideration. In this study, we have synthesized methylammonium lead triiodide (MAPbI3) SCs using polyethylene glycol (PEG) and polystyrene (PS) polymers where PEG contains oxygen functionalities and PS does not. We studied the electrical properties of these SCs under dark and illumination conditions. It was observed that PEG-assisted SCs showed few defects with lower photocurrent as compared to the PS-assisted ones because of defect-mediated conductivity. The results are further verified by transient current response, responsivity, and capacitance–frequency measurements. The present study sheds light on the polymer selection for the growth of MHP SCs and their optoelectronic properties.