Highly porous lithium-ion conducting solvent-free poly(vinylidene fluoride-co-hexafluoropropylene)/poly(ethyl methacrylate) based polymer blend electrolytes for Li battery applications

Poly(ethyl methacrylate) Composite Coatings Containing Halogen-Free Inorganic Additives with Flame-Retardant Properties

This investigation is motivated by the need for the development of polymer coatings containing inorganic flame-retardant materials (FRMs) and the replacement of toxic halogenated FRMs. A green strategy is reported for the fabrication of poly(ethyl methacrylate) (PEMA)-FRM composite coatings using a dip-coating method. The use of water-isopropanol co-solvent allows the replacement of regular toxic solvents for PEMA. The abilities to form concentrated solutions of high-molecular-mass PEMA and to disperse FRM particles in such solutions are the main factors in the fabrication of coatings using a dip-coating technique. Huntite, halloysite, and hydrotalcite are used as advanced FRMs for the fabrication of PEMA-FRM coatings. FTIR, XRD, SEM, and TGA data are used for the analysis of the microstructure and composition of PEMA-FRM coatings. PEMA and PEMA-FRM coatings provide corrosion protection of stainless steel. The ability to form laminates with different layers using a dip-coating method facilitates the fabrication of composite coatings with enhanced properties.

A Versatile Strategy for the Fabrication of Poly(ethyl methacrylate) Composites

Poly(ethyl methacrylate) (PEMA) is dissolved in ethanol, known to be a non-solvent for PEMA, due to the solubilizing ability of an added bile acid biosurfactant, lithocholic acid (LA). The ability to avoid traditional toxic and carcinogenic solvents is important for the fabrication of composites for biomedical applications. The formation of concentrated solutions of high molecular weight PEMA is a key factor for the film deposition using the dip coating method. PEMA films provide corrosion protection for stainless steel. Composite films are prepared, containing bioceramics, such as hydroxyapatite and silica, for biomedical applications. LA facilitates dispersion of hydroxyapatite and silica in suspensions for film deposition. Ibuprofen and tetracycline are used as model drugs for the fabrication of composite films. PEMA-nanocellulose films are successfully prepared using the dip coating method. The microstructure and composition of the films are investigated. The conceptually new approach developed in this investigation represents a versatile strategy for the fabrication of composites for biomedical and other applications, using natural biosurfactants as solubilizing and dispersing agents.

Characterization and Physical and Biological Properties of Tissue Conditioner Incorporated with Carum copticum L

Aim

One of the main problems in dentistry is the injury caused by the long-term application of an ill-fitting denture. The existence of multiple microorganisms along with the susceptibility of the tissue conditioners to colonize them can lead to denture stomatitis. This study is aimed at developing a tissue conditioner incorporated with Carum copticum L. (C. copticum L.) for the effective treatment of these injuries.

Materials and Methods

The Carum copticum L. essential oil composition was determined by gas chromatography-mass (GC-mass) spectrometry. The antimicrobial activity of the essential oil against the standard strains of bacterial and fungal species was determined by broth microdilution methods as suggested by the Clinical and Laboratory Standards Institute (CLSI). The physical and chemical properties of the prepared tissue conditioner were investigated by viscoelasticity, FTIR assays, and the release study performed. Furthermore, the antibiofilm activity of the Carum copticum L. essential oil-loaded tissue conditioner was evaluated by using the XTT reduction assay and scanning electron microscopy (SEM).

Results

The main component of the essential oil is thymol, which possesses high antimicrobial activity. The broth microdilution assay showed that the essential oil has broad activity as the minimum inhibitory concentration was in the range of 32-128 μg mL^-1. The viscoelasticity test showed that the essential oil significantly diminished the viscoelastic modulus on the first day. The FTIR test showed that Carum copticum L. essential oil was preserved as an independent component in the tissue conditioner. The release study showed that the essential oil was released in 3 days following a sustained release and with an ultimate cumulative release of 81%. Finally, the Carum copticum L. essential oil exhibited significant activity in the inhibition of microbial biofilm formation in a dose-dependent manner. Indeed, the lowest and highest amounts of biofilm formation on the tissue conditioner disks are exhibited in the Streptococcus salivarius and Candida albicans by up to 22.4% and 71.4% at the 64 μg mL^-1 concentration of C. copticum L. with a statistically significant difference (P < 0.05).

Conclusion

The obtained results showed that the Carum copticum L. essential oil-loaded tissue conditioner possessed suitable physical, biological, and release properties for use as a novel treatment for denture stomatitis.

High electrochemical and mechanical performance of zinc conducting-based gel polymer electrolytes

Zinc ionic conducting-based gel polymer electrolytes (GPEs) were fabricated from carboxymethyl cellulose (CMC) and three different zinc salts in a mass ratio ranging within 0–30 wt%. The effects of zinc salt and loading level on the structure, thermal, mechanical, mechanical stability, and morphological properties, as well as electrochemical properties of the GPEs films, were symmetrically investigated. The mechanical properties and mechanical stability of CMC were improved with the addition of zinc acetate, zinc sulphate, and zinc triflate, approaching the minimum requirement of a solid state membrane for battery. The maximum ionic conductivity of 2.10 mS cm⁻¹ was achieved with the addition of 15 wt% zinc acetate (ZnA), GPE_A15. The supported parameters, indicating the presence of the amorphous region that likely supported Zn²⁺ movement in the CMC chains, were clearly revealed with the increase in the number of mobile Zn²⁺ carriers in FT-IR spectra and the magnitude of ionic transference number, the decrease of the enthalpy of fusion in DSC thermogram, and the shifting to lower intensity of 2θ in XRD pattern. The developed CMC/ZnA complex-based GPEs are very promising for their high ionic conductivity as well as good mechanical properties and the ability for long-term utilization in a zinc ion battery.

Porous (PVDF-HFP/PANI/GO) ternary hybrid polymer electrolyte membranes for lithium-ion batteries

A poly(vinylidene co-hexafluoropropylene) (PVDF-HFP) membrane is functionalized with polyaniline (PANI) and graphene oxide (GO) nanoparticles. The obtained PVDF-HFP polymer electrolyte membranes (PEMs) have been characterized and implemented in lithium-ion batteries. As a result, the PVDF-HFP/PANI membrane shows the highest ionic conductivity (IC) of 1.04 × 10⁻³ mS cm⁻¹ compared to pristine PVDF-HFP and PVDF-HFP/PANI/GO ternary membrane; however, PANI addition decreases the tensile strength of the PVDF-HFP membrane from 4.2 MPa to 2.8 MPa. Therefore, GO is introduced to recover the reduced mechanical strength of the PVDF-HFP/PANI membrane. The obtained PVDF-HFP/PANI/GO ternary membrane shows a remarkable improvement in tensile strength of up to 8.8 MPa; however, slight reduction is observed in the ionic conductivity of 6.64 × 10⁻⁴ mS cm⁻¹. Furthermore, the PVDF-HFP/PANI/GO ternary membrane exhibits outstanding thermal and mechanical stabilities, improved morphology, highest electrolyte uptake (367.5%) and an excellent porosity of around 89%. Moreover, the PVDF-HFP/PANI/GO ternary PEM has been successfully applied in a lithium-ion battery, which can retain over 95% capacity after 30 cycles. Therefore, the proposed PVDF-HFP/PANI/GO ternary membrane can be a promising candidate as a separator in future lithium-ion batteries.

A poly(vinylidene co-hexafluoropropylene) (PVDF-HFP)/polyaniline (PANI/graphene oxide (GO) ternary PEM in lithium ion battery.

Experimental and Theoretical Study of Ionic Pair Dissociation in a Lithium Ion-Linear Polyethylenimine-Polyacrylonitrile Blend for Solid Polymer Electrolytes

Herein, we report the preparation and characterization of a novel polymeric blend between linear polyethylene imine (PEI) and polyacrylonitrile (PAN), with the purpose of facilitating the dissociation of lithium perchlorate salt (LiClO₄) and thus to enhance Li ion transport. It is a joint theoretical and experimental procedure for evaluating and thus demonstrating the lithium salt dissociation. The procedure implies the correlation between the theoretical pair distribution function (PDF) and conventional X-ray diffraction (XRD) by means of a molecular dynamics (MD) approach. Additionally, we correlated the experimental and theoretical Raman and infrared spectroscopy for vibrational characterization of the lithium salt after dissociation in the polymeric blend. We also performed confocal Raman microscopy analysis to evidence the homogeneity on the distribution of all components and the LiClO₄ dissociation in the polymer blend. The electrochemical impedance analysis confirmed that the Li-PAN-PEI blend presents a slightly better lithium conductivity of ∼8 × 10^-7 S cm^-1. These results suggest that this polymer blend material is promising for the development of novel fluorine-free solid polymer lithium ion electrolytes, and the methodology is suitable for characterizing similar polymeric systems.

Lithium Ion Conduction in PVdC-co-AN Based Polymer Blend Electrolytes Doped with Different Lithium Salts

Polymer electrolytes prepared by the complexation of lithium salts with poly(ethylene oxide) (PEO) and poly(vinylidene chloride-co-acrylonitrile) (PVdC-co-AN) will be of great use as separators in lithium polymer batteries. The amorphous nature of the blend electrolyte shows that the conductivity increases by the addition of lithium salts. The presence of C≡N and C=N in PVdC-co-AN are confirmed from the Fourier transform infrared studies. Among the various lithium salts studied, lithium trifluoro methane sulfonoimide [LiN(CF3SO2)2] based electrolyte exhibits the highest ionic conductivity of the order of 0.265 × 10−5 Scm−1 at room temperature. The sample having a maximum ionic conductivity PEO(80 wt%)/PVdC-co-AN(20 wt%)/LiN(CF3SO2)2(8 wt%) is supported by the lower optical band gap in UV-Visible analysis and low intensity in luminescence studies. Two and three dimensional topographic images of the above sample reveal the presence of micropores. Thermal stability of the prepared electrolytes is studied by thermo gravimetric/differential thermal analysis. Using differential scanning calorimetric analysis, the minimum glass transition temperature (30°C) is observed for the sample doped with LiN(CF3SO2)2. The cyclic voltammetric studies reveal the strong capacitive behavior of the prepared polymer electrolytes. The electrochemical stability windows for the prepared samples are observed using linear sweep voltammetry.

Preparation of LAGP/P(VDF-HFP) polymer electrolytes for Li-ion batteries

LAGP as a lithium ion conducting filler, was added into P(VDF-HFP) based gel polymer electrolytes to improve electrochemical performances.

Structural and Electrochemical Analysis of PMMA Based Gel Electrolyte Membranes

New gel polymer electrolytes containing poly(vinylidene chloride-co-acrylonitrile) and poly(methyl methacrylate) are prepared by solution casting method. With the addition of 60 wt.% of EC to PVdC-AN/PMMA blend, ionic conductivity value0.398×10-6 S cm−1has been achieved. XRD and FT-IR studies have been conducted to investigate the structure and complexation in the polymer gel electrolytes. The FT-IR spectra show that the functional groups C=O and C≡N play major role in ion conduction. Thermal stability of the prepared membranes is found to be about 180°C.