Semi-interpenetrating Polymer Network Structure Research Articles

Electrically conductive functionalization of cured polyether ether ketone with improved bioactivity by surface-polymerization of polyaniline

The electrically conductive polyether ether ketone (PEEK) holds great promise for antibacterial and cell growth promotion under electrical stimulation, making it a promising material for next-generation implants. However, it is a significant challenge for electrically conductive functionalization of PEEK, especially for cured or shaped PEEK. In addition, PEEK’s bioactivity is still underdeveloped at present. Here, an electrically conductive PEEK with improved bioactivity is prepared through surface-polymerization of polyaniline (PANI) in the shell layer of cured PEEK. Impressively, an extremely high conductivity of 5.2 × 10−2 S/cm is achieved for the conductive PEEK among all the reported PANI/PEEK composites or blends with the optimal conductivity of 3.0 × 10−4 S/cm. It has been demonstrated that the conductive shell layer of the conductive PEEK features a PANI/PEEK semi-interpenetrating polymer network structure, explaining its conductivity. Improved cell proliferative activity is also disclosed for the conductive PEEK compared to that of the pure PEEK, and good biocompatibility and osteogenesis properties are further confirmed for the fabricated conductive PEEK scaffold. This conductive functionalization approach offers a significant advancement for developing next-generation biological implants and could be applied to other cured polymers as well.

Electro-induced biochar-embedded-SIPN hydrogel as discrete bipolar electrodes for selective oxidation and enrichment of trace thallium(Ι)

Electrochemical techniques for thallium (Tl) treatment face a substantial challenge linked to the concentration of Tl(I), hindering the efficient removal and recovery of trace Tl(I) (μg L−1). In response, we synthesized hydrogel particles incorporating biochar (BC) within semi-interpenetrating polymer networks (SIPN), showcasing robust selectivity for Tl(I). These biochar-embedded-SIPN hydrogel particles (BC-SIPN particles), employed as dispersed electrodes, facilitated the targeted oxidation and enrichment of Tl(I) through electro-induction. Research outcomes elucidate the adept mitigation of the “efficiency-dependent concentration” behavior by electro-induced BC-SIPN particles during the reaction process. Under optimized conditions (pH 12, 2 V cm−1, 30 min), Tl(I) removal efficiency surpassed 98 % at an initial concentration of 100 μg L−1. The SIPN structure enhanced particle stability, and after seven cycles of enrichment in a 100 μg L−1 Tl(I) environment, BC-SIPN particles achieved a Tl content of 0.073 %, meeting Tl mineral content standards and promoting the recovery of scarce Tl resources. First-principles calculations underscore the pivotal role of hydrogen bond-electrostatic interactions between TlOH(aq) and particles in driving selective Tl(I) adsorption. Insights from quenching and capture reactions reveal a predominant direct oxidation pathway of Tl(I) to Tl(Ⅲ), complemented by indirect oxidation driven by reactive oxygen species, including OH, O- 2 and 1O2. This study presents an innovative approach for trace Tl(I) wastewater treatment, simultaneously mitigating the “efficiency-dependent concentration” phenomenon, and underscores the transformative potential of electro-induced BC-SIPN hydrogel particles in offering sustainable solutions for Tl(I) removal and resource recovery in environmental stewardship.

Capsaicin-based silicone antifouling coating with enhanced interlocking adhesion via SIPN

Silicone-based coatings generally exhibit excellent dynamic fouling release due to their low surface energy and elastic modulus. However, the poor adhesion of these coatings at the interface between the coating and the substrate, as well as deficient static antifouling capabilities, severely deteriorate their antifouling properties over extended periods. Herein, an epoxy-poly(dimethylsiloxane)/capsaicin (EP-PDMS/CAP) coating with highly enhanced interfacial adhesion and remarkable antifouling performances was prepared. The coating adhesion strength of the EP-PDMS/CAP has been improved by more than 5 times compared to a PDMS control coating (from 0.4 MPa to 2.04 MPa) by forming a semi-interpenetrating polymer network (SIPN) structure between the epoxy and PDMS layers. The EP-PDMS/CAP coating achieved the superior antifouling effects in both static and dynamic conditions, the anti-bacterial rate was as high as 96.8 %, and the anti-algal adhesion rate to the green algae Chlorella increased by 95.7 %, due to the synergistic effects of the fouling release performance from the PDMS coating and the fouling prevention of capsaicin. Furthermore, the EP-PDMS/CAP coating was proven to be extremely stable in different treatments such as acid/basic solutions, air oven heating test, and cyclic sand abrasion, showing great potential for anti-biofouling under aggressive conditions. This work provides a promising pathway towards the development of high-performance silicone-based composite coatings for efficient marine anti-biofouling.

Skin-adhesive lignin-grafted-polyacrylamide/hydroxypropyl cellulose hydrogel sensor for real-time cervical spine bending monitoring in human-machine Interface

Developing a straightforward method to produce conductive hydrogels with excellent mechanical properties, self-adhesion, and biocompatibility remains a significant challenge. While current approaches aim to enhance mechanical performance, they often require additional steps or external forces for fixation, leading to increased production time and limited practicality. A novel lignin-grafted polyacrylamide/hydroxypropyl cellulose hydrogel (L-g-PAM/HPC hydrogel) with a semi-interpenetrating polymer network structure had been developed in this research that boasted exceptional adhesion to the skin (∼68 kPa) and stretchability properties (∼1637 %) compared to PAM-based hydrogels. By incorporating conductive additives such as silver nanowires and carbon nanocages to construct a bridge-like structure within the hydrogel matrix, the resulting AgC@L-g-PAM/HPC hydrogel exhibited impressive electrical conductivity, surpassing that of other PAM-based hydrogels relying on MXene, with a maximum value of 0.76 S/m. Furthermore, the AgC@L-g-PAM/HPC hydrogel retained its efficient electrical signal transmission capability even under mechanical stress. These make it an ideal flexible strain sensor capable of detecting various human motions. In this study, a smart real-time monitoring system was successfully developed for tracking cervical spine bending, serving as an extension for monitoring human activities.

Dual-bionic, fluffy, and flame resistant polyamide-imide ultrafine fibers for high-temperature air filtration

Particulate matter (PM) pollution has been acknowledged as a serious health hazard globally, calling for thermo-stable air filtration materials to remove particles from high-temperature emission sources. However, the commercial filter media suffer from large fiber diameter and compact assembling architecture, resulting in the difficulty in achieving a balance between filtration efficiency and pressure drop. Herein, a dual-bionic strategy is proposed to prepare high-performance polyamide-imide (PAI) fibrous assemblies for the application in high-temperature air filtration. Inspired by the fact that Masson Pine shows attractive capability of particle retention, PAI fibers with biomimetic groove structure are constructed via asynchronous phase separation principle, meanwhile showing fluffy assembling architecture via humidity-induced electrospinning technology. Furthermore, the stiff cellulose networks within loofah sponges, which contributes to robust mechanical property, inspired us to construct semi-interpenetrating polymer network (semi-IPN) structure within PAI fibers. Benefitting from the hierarchical structure and intrinsic flame resistant property, the resulting PAI ultrafine fibers present distinct characteristics of high specific surface area (25.97 m2/g) and high porosity (90.44 %), contributing to a high PM2.5 filtration efficiency (98 % at severe pollution), a low pressure drop (only 46.35 Pa), and satisfying long serving time at 220℃. The successful fabrication of PAI filter media brings new insights for designing next-generation thermo-stable air filters.

Judicious Design and Rapid Manufacturing of a Flexible, Mechanically Resistant Liquid-Like Coating with Strong Bonding and Antifouling Abilities.

Fluorine-free liquid-repellent coatings have been highly demanded for a variety of applications. However, rapid formation of coatings possessing outstanding oil repellency and strong bonding ability as well as good mechanical strength (e.g., bendability, impact resistance, and scratch resistance) remains a grand challenge. Herein, a robust strategy to rapidly create fluorine-free oil-repellent coatings in only 30 s via rational design of a semi-interpenetrating polymer network structure is reported. The resulting coating manifests strong bonding capability both in air and underwater. More importantly, it not only provides unprecedented oil repellency, even to high-viscosity crude oil, but also achieves both excellent bendability and hardness. This simple yet effective design strategy opens up a new avenue to manufacture multifunctional materials and devices with desirable features and structural complexities for applications in sustainable antifouling, drag reduction, nondestructive transportation, liquid collection, and biomedicine, among other areas.

From dual-aerogels with semi-interpenetrating polymer network structure to hierarchical porous carbons for advanced supercapacitor electrodes

Herein, dual-aerogels of resorcinol-formaldehyde and polyvinyl alcohol (RF/PVA) with semi-interpenetrating polymer network (semi-IPN) structure are prepared and applied as precursors for preparing the hierarchical porous carbons. PVA serves as the critical skeletal template for macropores and supports the three-dimensional architecture, while KOH impels the increment of micropores and the formation of mesopores, both enlarging the specific surface area. More intriguing, the pore structure and surface area can be tailored by controlling the mass ratio of resorcinol to PVA, thus optimizing the electrochemical performance. As-obtained DAGC-1 with a large specific surface area of 2076 m2 g−1 and three-dimensional hierarchical porous structure exhibits a superior specific capacitance of 320 F g−1 at 1 A g−1 in three-electrode system. Meanwhile, DAGC-1 assembled symmetrical supercapacitor delivers an elevated energy output of 59.8 Wh kg−1 at 350 W kg−1 in EMIMBF4 electrolyte with a wide potential range of 3.5 V. Our work provides a novel synthesis approach deriving hierarchical porous carbons from dual-aerogels with semi-IPN structure, serving as a new highlight for efficient energy storage.

Injectable Fibrin/Polyethylene Oxide Semi-IPN Hydrogel for a Segmental Meniscal Defect Regeneration

Background: Meniscal deficiency from meniscectomy is a common situation in clinical practices. Regeneration of the deficient meniscal portion, however, is still not feasible. Purpose: To develop an injectable hydrogel system consisting of fibrin (Fb) and polyethylene oxide (PEO) and to estimate its clinical potential for treating a segmental defect of the meniscus in a rabbit meniscal defect model. Study Design: Controlled laboratory study. Methods: The Fb/PEO hydrogel was fabricated by extruding 100 mg·mL-1 of fibrinogen solution and 2,500 U·mL-1 of thrombin solution containing 100 mg·mL-1 of PEO through a dual-syringe system. The hydrogels were characterized by rheological analysis and biodegradation tests. The meniscal defects of New Zealand White male rabbits were generated by removing 60% of the medial meniscus from the anterior side. The removed portion included the central portion. The Fb/PEO hydrogel was injected into the meniscal defect of the experimental knee through the joint space between the femoral condyle and tibial plateau at the anterior knee without a skin incision. The entire medial menisci from both knees of each rabbit were collected and photographed before placement in formalin for histological processing. Hematoxylin and eosin, safranin O, and immunohistochemical staining for type II collagen was performed. The biomechanical property of the regenerated meniscus was evaluated using a universal tensile machine. Results: The Fb/PEO hydrogel was fabricated by an in situ gelation process, and the hydrogel displayed a semi-interpenetrating polymer network structure. We demonstrated that the mechanical properties of Fb-based hydrogels increased in a PEO-dependent manner. Furthermore, the addition of PEO delayed the biodegradation of the hydrogel. Our in vivo data demonstrated that, as compared with Fb hydrogel, Fb/PEO hydrogel injection into the meniscectomy model showed improved tissue regeneration. The regenerated meniscal tissue by Fb/PEO hydrogel showed enhanced tissue quality, which was supported by the histological and biomechanical properties. Conclusion: The Fb/PEO hydrogel had an effective tissue-regenerative ability through injection into the in vivo rabbit meniscal defect model. Clinical Relevance: This injectable hydrogel system can promote meniscal repair and be readily utilized in clinical application.

Robust and Highly Ion-Conducting Gel Polymer Electrolytes with Semi-Interpenetrating Polymer Network Structure

Here we report gel polymer electrolytes (GPEs) formed by the film casting of the solution containing poly(ethylene glycol) methyl ether methacrylate (PEGMA) and trimethylolpropane ethoxylate triacrylate (ETPTA) with poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), followed by the thermal radical polymerization and liquid electrolyte absorption. The resulting GPEs show a semi-interpenetrating polymer network (SIPN) structure that provides film robustness which is investigated by morphological, structural, and electrochemical studies. Particularly, the GPE prepared by the composition of 98 mol% PEGMA and 2 mol% ETPTA in the presence of 40 wt% of PVDF-HFP (relative to total amount of PEGMA and ETPTA) manifests large ionic conductivity (1.46 × 10−3 S cm−1) and tensile strength (6.28 MPa at elongation at break of 156%) at a room temperature due to large uptake of the liquid electrolyte (up to 267%) and SIPN structure. We also verify that the GPE is electrochemically stable up to 4.7 V (vs. Li/L+), suggesting it holds the great promise of a polymer electrolyte membrane for energy storages such as rechargeable batteries or supercapacitors.

Design and fabrication of novel core-shell nanoparticles for theranostic applications

Superparamagnetic iron oxide nanoparticles (SPIONs) were prepared by co-precipitation method, functionalized respectively with tetraethyl orthosilicate (TEOS) and 3-(trimethoxysilyl)propyl methacrylate (TMSPM), and monodispersed by filtration and centrifugation. The vinyl-functionalized monodispersed SPIONs were then coated with a shell of the novel dual-responsive hydrogel having semi-interpenetrating polymer network (semi-IPN) structure. The formulation of this hydrogel, which was designed and synthesized in the previous study, was based on sodium alginate (Alg-Na) polymer and temperature-sensitive N-isopropylacrylamide (NIPAA) and pH-sensitive N-ethylmaleamic acid (NEMA) monomers. Sodium alginate acting as a pore-forming agent has a key role in the generation of semi-IPN structure and significantly decreases the time to reach the equilibrium swelling. Totally, two series of core-shell nanoparticles (CSNs) with the same magnetic core and different shell thicknesses were fabricated and exposed to different tests including transmission electron microscopy (TEM), dynamic light scattering (DLS), magnetic property evaluations, and magnetic resonance imaging (MRI) measurements. The obtained results of these tests revealed that these CSNs have the potential to be used as new theranostic platforms for simultaneous cancer diagnosis and therapy.

Poly(ionic liquid)-polyethylene oxide semi-interpenetrating polymer network solid electrolyte for safe lithium metal batteries

Solid-state polymer electrolyte with high ionic conductivity and electrochemical stability is desirable for lithium metal batteries. A poly(ionic liquid)-polyethylene oxide semi-interpenetrating polymer network composite solid electrolyte for safe lithium metal batteries is designed to satisfy the demand of ionic conductivity, safety and electrochemical stability. This composite solid electrolyte is fabricated via polymerizing 1-vinyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (ionic liquid monomer) in polyethylene oxide matrix by one-step method. Differential scanning calorimetry results reveal that the crystallinity of composite solid electrolyte reduce to 15.5% comparing with polyethylene oxide solid electrolyte owing to the confinement of poly(ionic liquid) interpenetrating network. The semi-interpenetrating polymer network structure simultaneously endow the composite solid electrolyte with high ionic conductivity (6.12 × 10−4 S cm−1 at 55 °C) and wide electrochemical window (5.44 V vs. Li/Li+) and thermal decomposition temperature (280 °C). In order to verify the favorable electrochemical performance of composite solid electrolyte, we assemble the cells with LiFePO4/Li using the electrolyte. The reversible capacity of LiFePO4 is 147 mAh g−1 with high Coulombic efficiency (up to 99%) at the 0.2 C rate and 55 °C.

Synthesis and synergetic effects of ladder-like silsesquioxane/epoxy compositional gradient hybrid coating

A series of ladder-like silsesquioxane and their compositional gradient hybrid coatings with epoxy were fabricated by solution-diffuse technique, which involved pre-curing of epoxy followed by coating the silsesquioxane/tetrahydrofuran solution and then post-curing. The resulting material combined the advantages of the two components. The corresponding synergetic effects of the composite coating were evaluated by various coating characteristics, such as adhesion strength, hardness, thermal stability, flame retardancy, hydrophobicity, optical transparency and chemical resistance. The semi-interpenetrating polymer network structure can avoid serious phase separation at the interface between silicon and epoxy layer, and the gradient interface structure was proved by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Moreover, the influences of various ladder-like silsesquioxane and commercial linear polysiloxane on the performance of the ultimate coating were analyzed. Compared with the composite coating used linear polysiloxane, those containing ladder-like silsesquioxane behave significantly higher thermal stability, adhesion properties and chemical resistance. It is believed that the simple preparation method and excellent properties may promote large-scale application of the latter in the field of high-performance coatings.

A self-standing, UV-cured semi-interpenetrating polymer network reinforced composite gel electrolytes for dendrite-suppressing lithium ion batteries

A self-standing, flexible and lithium dendrite growth-suppressing composite gel polymer electrolyte membrane was designed for the use of room-temperature lithium ion batteries. The multi-functional composite semi-interpenetrating polymer network (referred to as “Cs-IPN”) electrolyte membrane was fabricated by combining a UV-cured ethoxylated trimethylolpropane triacrylate (ETPTA) macromer with alumina nanoparticles in the presence of liquid electrolyte and thermoplastic linear poly(ethylene oxide) (PEO). The polymer electrolyte membrane exhibits a semi-interpenetrating polymer network structure and a higher room temperature ionic conductivity, which impart the electrolyte with a significant cycling (120 mAh g−1 after 200 cycles) and a remarkable rate (137 mAh g−1 at 0.1 °C, 130 mAh g−1 at 0.5 °C, 119 mAh g−1 at 1 °C and 100 mAh g−1 at 2 °C) performance in Li/LiFePO4 battery. More importantly, the polymer electrolyte possesses superior ability to inhibit the growth of lithium dendrites, which makes it promising for next generation lithium ion batteries.

High-Performance Ionic Liquid-Based Gel Polymer Electrolyte Incorporating Anion-Trapping Boron Sites for All-Solid-State Supercapacitor Application.

A high-performance boron-containing gel polymer electrolyte (GPE) with semi-interpenetrating polymer network structure was successfully prepared by a rapid and easy one-step polymerization process assisted with UV light, exploiting poly(ethylene oxide) as a polymer host, the novel borate ester monomer as the cross-linker, and LiClO4 and EMIMBF4 both as the plasticizer and electrolytic salt, respectively. Owing to the incorporation of anion-trapping boron sites, the ionic conductivity of the as-prepared GPE at room temperature can be up to 5.13 mS cm-1. In addition, the boron-containing GPE (B-GPE) exhibits favorable mechanical strength, excellent thermal stability, and extremely low flammability. Moreover, the all-solid-state symmetric supercapacitor using B-GPE as the electrolyte and reduced graphene oxide as the electrode was fabricated and exhibited a broad potential window (3.2 V). The all-solid-state symmetric supercapacitor based on B-GPE can still reach a high energy density of 27.62 W h kg-1 with a power density of 6.91 kW kg-1 at a high current density of 5 A g-1. After 5000 cycles at a current density of 1 A g-1, the all-solid-state supercapacitor with B-GPE displays a decent capacitance retention of 91.2%.

Antioxidant proton conductive toughening agent for the hydrocarbon based proton exchange polymer membrane for enhanced cell performance and durability in fuel cell

The antioxidant toughening agent for the hydrocarbon based proton exchange polymer electrolyte membranes, cerium/organosiloxane polymer network (Ce/OSPN), is synthesized via sol-gel reaction. Ce/OSPN is introduced to the sulfonated poly(ether ether ketone) (SPEEK), a typical hydrocarbon type polymer electrolyte membrane, by formation of a semi-interpenetrating polymer network (semi-IPN) structure. As Ce/OSPN possesses superior properties to SPEEK in mechanical flexibility, proton conductivity, and oxidation stability than SPEEK, it resolves 3 inherent drawbacks of the pristine SPEEK membrane including (i) brittleness, (ii) low proton conductivity, and (iii) poor durability. Addition of 20 wt% Ce/OSPN (at Ce/silicon mol ratio = 0.10) enhances the elongation at break of the SPEEK membrane about twice. The power density of the MEA fabricated with the semi-IPN membrane is 208 mW cm−2, which is much higher than that of the pristine SPEEK membrane, 165 mW cm−2. The power density loss of the same semi-IPN membranes as determined by the Fenton's test is 4.8%, whereas those of pristine and semi-IPN membrane without cerium are 33.9% and 34.0%, respectively. This Ce/OSPN agent is expected to be applied to a variety of hydrocarbon based polymer electrolyte membranes.

Synthesis and characterization of a dyeable bio-based polyurethane/branched poly(ethylene imine) interpenetrating polymer network with enhanced wet fastness

Bio-based polyurethane is synthesized from biodegradable polycaprolactone, methylene diphenyl diisocyanate and 1,4-butanediol. The bio-based polyurethane is blended with branched polyethyleneimine by a solution casting method and further treated with glutaraldehyde. From nuclear magnetic resonance, Fourier-transform infrared spectroscopy, leaching tests and contact angle measurements, it was found that a semi-interpenetrating polymer network structure is induced by the glutaraldehyde treatment of the bio-based polyurethane/branched polyethyleneimine blend film, which resulting from the crosslinking of branched polyethyleneimine by imine bonds formed from the amine-aldehyde reaction between branched polyethyleneimine and glutaraldehyde. In addition, the glass transition temperature, Young’s modulus and the shape retention results show that the mechanical strength of bio-based polyurethane, which is weakened by the plasticizing effect of branched polyethyleneimine, is restored by the formation of the semi-interpenetrating network structure. We found that the bio-based polyurethane/branched polyethyleneimine with a semi-interpenetrating network shows a much higher affinity for Acid Red 4 than bio-based polyurethane, and the wet fastness of dye is significantly improved by the formation of the semi-interpenetrating network.

Dual-responsive semi-IPN copolymer nanogels based on poly (itaconic acid) and hydroxypropyl cellulose as a carrier for controlled drug release

Dual-responsive nanogels were prepared by polymerization of itaconic acid (IA) and copolymerization with methacrylic acid (MA) in aqueous solution of hydroxypropyl cellulose (HPC) and cross-linking with N, N′-methylenebisacrylamide (MBAm) through an easy and green process. FTIR spectroscopy, TEM, AFM, DLS and zeta potential studies confirmed the semi-interpenetrating (semi-IPN) polymer network structure of nanogels. The LCST of HPC was increased to a higher temperature than HPC’s intrinsic LCST, while the presence of the MA comonomer improved the hydrophobicity of the copolymer and reduced LCST to about body temperature and suppressed the excessive nanogel aggregation. It was found that the concentration of reactants impacted the process of nanogel formation. Additionally, an increasing of cross-linker concentration led to a reduced size of HPC nanogels. Besides, the diameter of nanogels was changed with the temperature and pH. TEM and AFM photographs of copolymer nanogels illustrated that the nanoparticles with small diameters (<100 nm) were prepared. With loading the doxorubicin into the copolymer nanogels, the particle size became larger (about 150 nm) and due to the electrostatic interaction of the cationic drug with anionic particles, the zeta potential was increased. Drug release processes were followed at pH = 5.0 and 7.4 and with 37- and 41-°C temperatures, respectively. The maximum in-vitro release studies of drug-loaded nanogels, which is 91% for the pH 5.0 buffer solution at 41 °C, demonstrated the temperature- and pH-sensitivity of prepared copolymer nanogels.

Polylactic acid/polyurethane blend reinforced with cellulose nanocrystals with semi-interpenetrating polymer network (S-IPN) structure

The aim of the current work was to prepare and characterize a cellulose nanocrystal reinforced semi-interpenetrated network (SIPN) derived from polylactic acid (PLA) and polyurethane (PU) polymers. SIPN films were prepared using solvent casting from 1,4-dioxane solution. The morphology, mechanical and thermal properties of the neat SIPN and its nanocomposite were characterized. A novel dispersion method was used, for the first time, to disperse the CNCs into the polyol. This method led to well dispersed CNCs in the SIPN, and at 1wt% CNC concentration, the elastic modulus of the nanocomposite was improved by 54% over an unreinforced SIPN. Additionally, the results indicated that the toughness of PLA, which is the main polymer phase, was improved. However, in the nanocomposite, CNCs formed a strong network and reinforced the PU phase, which resulted in a lower toughness of the final material. The storage modulus of the SIPN nanocomposite was higher than that of the neat PLA at temperatures higher than 55°C up to 100°C. This increase in thermomechanical properties indicates that the reinforced PU network in the PLA matrix can enhance the thermal behavior of material.

Gel Polymer Electrolytes Containing Anion-Trapping Boron Moieties for Lithium-Ion Battery Applications.

Gel polymer electrolytes (GPEs) based on semi-interpenetrating polymer network (IPN) structure for lithium-ion batteries were prepared by mixing boron-containing cross-linker (BC) composed of ethylene oxide (EO) chains, cross-linkable methacrylate group, and anion-trapping boron moiety with poly(vinylidene fluoride) (PVDF) followed by ultraviolet light-induced curing process. Various physical and electrochemical properties of the GPEs were systematically investigated by varying the EO chain length and boron content. Dimensional stability at high temperature without thermal shrinkage, if any, was observed due to the presence of thermally stable PVDF in the GPEs. GPE having 80 wt % of BC and 20 wt % of PVDF exhibited an ionic conductivity of 4.2 mS cm-1 at 30 °C which is 1 order of magnitude larger than that of the liquid electrolyte system containing the commercial Celgard separator (0.4 mS cm-1) owing to the facile electrolyte uptake ability of EO chain and anion-trapping ability of the boron moiety. As a result, the lithium-ion battery cell prepared using the GPE with BC showed an excellent cycle performance at 1.0 C maintaining 87% of capacity during 100 cycles.

Effects of acid–base cleaning procedure on structure and properties of anion-exchange membranes used in electrodialysis

In this paper, the consequences of traditional chemical cleaning on anion-exchange membrane structure and properties are thoroughly assessed. A homogeneous anion-exchange membrane (AEM1) and a heterogeneous one (AEM2) were subjected to ageing protocols in 2M NaOH and 2M HCl up to 700h at room temperature. Moreover, both membranes were exposed to cleaning cycles in which they were soaked alternatively in 0.1M HCl and 0.1M NaOH (30min each) from 100 to 400h to simulate the cleaning-in-place (CIP) procedure commonly used in industrial electrodialysis stacks. Exposure to strong acidic conditions did not result in severe changes of the physicochemical properties of AEM1. In contrast, strong alkaline conditions resulted in the transformation of poly(vinyl chloride) (PVC), i.e. the polymeric binder of AEM1, into a polyene structure as a consequence of dehydrochlorination enhanced by the presence of quaternary ammonium groups. Additionally, a small part of the functional sites were degraded by E1 or E2 elimination reactions. On the other hand, the cleaning cycles caused entanglement modifications in the semi-interpenetrating polymer network structure of AEM1. This was a consequence of the constant changing of the equilibrating solutions nature, which led to membrane inflate–deflate sequences. Therefore, membrane toughness was deteriorated, thus leading to the formation of cracks and fractures, as observed before on the same type of membrane after industrial electrodialysis in which traditional CIP is performed through acid–base sequences. In contrast, the heterogeneous AEM2 suffered degradation in strong acid conditions, whereas it seemed to be more resistant than AEM1 in strong alkaline conditions. Regarding the HCl–NaOH cycles, modifications were more significant for AEM2. This investigation permitted to correlate membrane ageing resulting from such ex-situ acid–base cleaning cycles and that suffered after conventional electrodialysis during traditional CIP.