Gel permeation chromatography (GPC) is a generally applied method for the mass analysis of various polymers and copolymers, but it inherently fails to provide additional important information such as ...the composition of copolymers. However, we will show that GPC measurements using different solvents can yield not just the correct molecular weight but the composition of the copolymer. Accordingly, artificial neural networks (ANNs) have been developed to process the data of GPC measurements and determine the molecular weight and the chemical composition of the copolymers. The target values of the ANNs were obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance (NMR) spectroscopy. Our GPC–ANN method is demonstrated by the analysis of various poloxamers, i.e., poly(ethylene oxide) (PEO)–poly(propylene oxide) (PPO) block copolymers. Two ANNs were constructed. The first one (ANN_1) works in a wider mass range (from 900 to 12,500 dalton), while the second one (ANN_2) produces more output values. ANN_2 can thus predict seven characteristic copolymer parameters, namely, two average molecular weights, the average weight fraction of the EO unit, and four average numbers of the repeat units. The correlation between the experimentally obtained outputs and the predicted ones is high (r > 0.98). The accuracy of the ANNs is very convincing, and both ANNs predict the number-average molecular weight (M n) with an accuracy below 5%. Furthermore, this work is the first step for creating an open database and applications extending the use of the GPC–ANN method for the analysis of copolymers.
The development of electrospun tissue engineering scaffolds using silk fibroin and polycaprolactone (PCL) has been reported. The challenge in this system is the design of a suitable solvent with high ...stability. In this study, a mat was electrospun with PCL‐fibroin fibers using an emulsion consisting of PCL and a blend of fibroin and polyethylene oxide (PEO). The effects of different concentrations of fibroin and PEO and ratios of formic acid: distilled water (FA:DW, solvent for fibroin and PEO) and chloroform: formic acid (Chl:FA, solvent for PCL) were studied. The FA:DW and Chl:FA ratios of 70:30 were proved to make an optimized and stable solvent system. In addition, by controlling the water absorption of the mat, we optimized its weight loss and maintained its integrity for up to 14 days. Also, the mechanical and cell attachment properties were as expected. Chorioallantoic membrane (CAM) assay exhibited the potential of the mats to induce angiogenesis. Furthermore, subcutaneous implantation in a mouse model elicited no significant inflammatory response. This study provides a simple and promising electrospinning fabrication with an optimized solvent system for tissue engineering applications.
•An asymmetrical flow field-flow fractionation method was developed to characterize the molar mass distribution of polyethylene oxide in abuse deterrent opioid formulation.•AF4 can server as an ...orthogonal method to SEC for PEO less than 1 MDa•AF4 was more efficient in characterizing PEO larger than 1 MDa.•Baseline determination for RI detection in data processing is critical in obtaining reliable and repeatable molar mass results.•PEO molar mass degradation during manufacturing process and manipulation can be studied by AF4
High molar mass polyethylene oxide (HM-PEO) is commonly used to enhance the mechanical strength of solid oral opioid drug products to deter abuse. Because the properties of PEO depend on molar mass distribution, accurately determining the molar mass distribution is a necessary part of understanding PEO's role in abuse-deterrent formulations (ADF). In this study, an asymmetrical flow field-flow fractionation (AF4) analytical procedure was developed to characterize PEO polymers with nominal molar masses of 1, 4 or 7 MDa as well as those from in-house prepared placebo ADF. The placebo ADF were manufactured using direct compress or hot-melt-extrusion methods, and subjected to physical manipulation, such as heating and grinding before measurement by AF4 were performed. The molar mass distribution characterized by AF4 revealed that PEO was sensitive to thermal stress, exhibiting decreased molar mass with increased heat exposure. The optimized AF4 method was deemed suitable for characterizing HM-PEO, offering adequate dynamic separation range for PEO with molar mass from 100 kDa to approximately 10 MDa.
Lineal (poloxamers or Pluronic
) or X-shaped (poloxamines or Tetronic
) amphiphilic tri-block copolymers of poly(ethylene oxide) and poly(propylene oxide) (PEO-PPO-PEO) have been broadly explored for ...controlled drug delivery in different regenerative medicine approaches. The ability of these copolymers to self-assemble as micelles and to undergo sol-to-gel transitions upon heating has endowed the denomination of "smart" or "intelligent" systems. The use of PEO-PPO-PEO copolymers as gene delivery systems is a powerful emerging strategy to improve the performance of classical gene transfer vectors. This review summarizes the state of art of the application of PEO-PPO-PEO copolymers in both nonviral and viral gene transfer approaches and their potential as gene delivery systems in different regenerative medicine approaches.
In this study, modified fibrous mats of poly(ethylene oxide) (PEO) were fabricated through the versatile technique of electrospinning. Acrylic monomers were added to PEO with different composition ...ratios, and the mats were irradiated. The kinetics of photo-cross-linking reaction in the presence of the acrylic cross-linkers, as well as the structural, thermal and mechanical properties of the nanofibers, were studied. The morphology of the fibrous membranes before and after water treatment was monitored, and the insoluble fraction of the fibers was measured. As a result, by tuning the photo-cross-linking reaction, the control over fibers properties was feasible. The photo-cured PEO-based nanofibrous mats showed the solubility resistance needed to use them as membranes and to apply them in aqueous environments, as in water treatment processes and biomedical applications.
Graphical Abstract
Polyethylene oxide (PEO) solid electrolytes are regarded as a promising candidate for all‐solid‐state lithium batteries owing to their high safety and interfacial compatibility. However, PEO ...electrolyte is plagued by relatively weak structural strength and unsatisfactory Li+ conductivity. Herein, a mechanically strong and Li+ conductively favorable cellulosic scaffold of PEO is fabricated through amino (‐NH2) modification and g‐C3N4 (CN) incorporation of bacterial cellulose (BC) under a microbial circumstance. The biologically ‐NH2 modified BC (B‐NBC) is entangled with CN nanosheets (CN@B‐NBC) through an in situ secretion of nanocellulose followed by hydrogen bond‐induced self‐assembly. The ‐NH2 groups from B‐NBC weaken the complexation of Li+ with its counterpart, thus facilitating the release of more free Li+. CN with strong C‐N covalence and extra lone electrons of N further strengthens the BC skeleton and meanwhile offers sufficient anchors for Li+ migration. After infiltrating by LiTFSI/PEO (LP), the LP/CN@B‐NBC composite solid electrolyte (CSE) exhibits high lithium transference number and ionic conductivity. Upon coupling with LiFePO4 cathode, the full battery exhibits a remarkably high specific capacity, superior rate capability, and decent cycling stability. This work pioneers the attempts of chemical decoration and ingredient incorporation of BC architecture in CSE with the aid of a bottom‐up biosynthetic avenue.
Mechanically strong and Li+ conductively favorable LP/CN@B‐NBC composite solid electrolyte (CSE) is fabricated via a biosynthetic process involving glucose monomer modification and CN aerosol deposition. Owing to the moderate complexation between Li+ and N active sites, the LP/CN@B‐NBC exhibits high Li+ conductivity and transference number, which guarantees superior electrochemical performance after being assembled into Li batteries.
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•Wide-field surface plasmon resonance microscope of PEO/PAA brushes were presented.•The electrical conductivity and refractive index of the PEO/PAA brushes increase with the increase ...of solvent pH.•Theoretical and experimental approaches study the sensitivity of a WF-SPRM utilizing Au-(PEO/PAA) polyelectrolyte layers.•The S/N ratio for the Au-(PEO/PAA PEBs) layer is 20 ± 1, indicating improved sensing performance compared to the Au-layer.•The SPR discrete particle model is introduced to describe the detection principle for discrete particles.
Wide-field surface plasmon resonance microscope (WF-SPRM) based on polyethylene oxide/polyacrylic acid (PEO/PAA) polyelectrolyte brushes (PEBs) is presented for particle detection application. PEO acts as an H-bond acceptor, while PAA serves as an H-bond donor, forming hydrogen-bonding complexes within the brushes. Morphological, chemical, and crystal structural analyses confirm that the PEO/PAA brushes undergo a transition from a collapsed to a stretched state as the solvent pH is increased from 1 to 10. This pH-dependent change also renders the PEO/PAA brushes more hydrophilic. Additionally, the electrical conductivity and refractive index of the PEO/PAA brushes increase concomitantly with the increase of solvent pH. Furthermore, theoretical and experimental approaches study the sensitivity of WF-SPRM utilizing Au-(PEO/PAA) polyelectrolyte layers. The theoretical sensitivity of WF-SPRM is enhanced from 118.5 deg./RIU for the Au-layer to 178.1 deg./RIU for Au-(PEO/PAA PEBs). Moreover, the signal-to-noise ratio for the Au-(PEO/PAA PEBs) layer is 20 ± 1, indicating improved sensing performance compared to the Au-layer (signal-to-noise ratio of 6 ± 1). A mathematical model to describe the discrete particle detection by WF-SPRM is presented, where results demonstrate a good agreement between the calculated intensity profile and experimental data.
In this work we implement a new methodology to study structural and mechanical properties of systems having spherical and planar symmetries throughout Molecular Dynamics simulations. This methodology ...is applied here to a drug delivery system based in polymersomes, as an example. The chosen model drug was the local anesthetic prilocaine due to previous parameterization within the used coarse grain scheme. In our approach, mass density profiles (MDPs) are used to obtain key structural parameters of the systems, and pressure profiles are used to estimate the curvature elastic parameters. The calculation of pressure profiles and radial MPDs required the development of specific methods, which were implemented in an in-house built version of the GROMACS 2018 code. The methodology presented in this work is applied to characterize poly(ethylene oxide)-poly(butadiene) polymersomes and bilayers loaded with the model drug prilocaine. Our results show that structural properties of the polymersome membrane could be obtained from bilayer simulations, with significantly lower computational cost compared to whole polymersome simulations, but the bilayer simulations are insufficient to get insights on their mechanical aspects, since the elastic parameters are canceled out for the complete bilayer (as consequence of the symmetry). The simulations of entire polymersomes, although more complex, offer a complementary approach to get insights on the mechanical behavior of the systems.
Lithium (Li) metal anode (LMA) is highly considered as a desirable anode material for next-generation rechargeable batteries because of its high specific capacity and the lowest reduction potential. ...However, uncontrollable growth of Li dendrites, large volume change, and unstable interfaces between LMA and electrolyte hinder its practical application. Herein, a novel in situ formed artificial gradient composite solid electrolyte interphase (GCSEI) layer for highly stable LMAs is proposed. The inner rigid inorganics (Li
S and LiF) with high Li
ion affinity and high electron tunneling barrier are beneficial to achieve homogeneous Li plating, while the flexible polymers (poly(ethylene oxide) and poly(vinylidene fluoride)) on the surface of GCSEI layer can accommodate the volume change. Furthermore, the GCSEI layer demonstrates fast Li
ion transport capability and increased Li
ion diffusion kinetics. Accordingly, the modified LMA enables excellent cycling stability (over 1000 h at 3 mA cm
) in the symmetric cell using carbonate electrolyte, and the corresponding Li-GCSEI||LiNi
Co
Mn
O
full cell demonstrates 83.4% capacity retention after 500 cycles. This work offers a new strategy for the design of dendrite-free LMAs for practical applications.
•A reactive polyurethane with multiple reactions toward silicon is prepared.•The binder stabilizes silicon anode with multiple chemical and H-bond interaction.•The PEO segments of the polyurethane ...binder facilitate transportation of lithium ions.•A capacity retention of 63% after a 300-cycle charge/discharge test has been recorded.
Chemically reactive groups (2,2-dimethyl-1,3-dioxane-4,6‑dione (Meldrum's acid, MA) and poly(ethylene oxide) (PEO) segments are incorporated to polyurethanes as binders of silicon anode for lithium ion batteries, aiming to address the volume change issue of the silicon anode in lithiation/delithiation cycles. The polymeric binder builds up multiple interaction to silicon surfaces, including hydrogen bonding between the urethane linkages of the bonder and silanol groups of silicon surfaces and covalent linkages through the addition reaction between ketene groups (generated from MA thermolysis reaction) and silanol groups of silicon surfaces. Self-dimerization of ketene groups also results in crosslinked structure of the binder. Both of the above-mentioned interaction and crosslinked structure contribute to stabilize the silicon anode materials. Moreover, the PEO segments facilitate the transportation of lithium ions and increase the ion conductivity of the anode. Consequently, the corresponding silicon anode is workable at a high C rate (0.8C) to demonstrate a specific capacity of approximately 1,785 mAh g − 1 and a capacity retention of 58% after a 600-cycle charge/discharge test. Morphological observation on the anode materials after a 300-cycle test indicates that the reactive PU binder could effectively depress cracks and interphase separation of the anode materials caused by the lithiation/delithiation-induced volume changes. The prepared binder also exhibits stabilization on the solid electrolyte interphase (SEI) layer and prevent anode material delamination. The results demonstrate a successful example of designs and preparation of multi-functional binders for silicon anodes.
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