Sulfonated Poly Ether Ether Ketone Research Articles

Enhanced performance of novel carbon nanotubes - sulfonated poly ether ether ketone (speek) composite proton exchange membrane in mfc application

Sulfonated poly ether ether ketone (SPEEK) nanocomposite proton exchange membrane (PEM) was prepared by incorporating multi-walled carbon nanotubes (CNT) at different weight percentages for microbial fuel cell (MFC) applications. Physico-chemical, thermal, mechanical and morphological characteristics of the prepared CNT-SPEEK composite membranes were analyzed using various techniques. Further, the water uptake capacity, Ion exchange capacity (IEC) and MFC performance of the CNT-SPEEK composite membranes were evaluated and compared with the pristine SPEEK membrane. Results show that incorporation of CNTs in SPEEK membranes exhibited a better water uptake capacity (34.18%–36.02%) and IEC (1.94–2.15 meq/g) compared to the SPEEK membrane. Improvement in membrane properties resulted in 2-fold higher power density compared to SPEEK membrane. Composite membrane with 0.75% CNT-SPEEK produced the higher power density (1.77 W/m2) in comparison with all the membranes evaluated. Chemical oxygen demand (COD) removal efficiency values of the MFC with SPEEK composite membranes were also found to be around 90%. Overall, the results reveal that CNT-SPEEK composite membrane as a potential PEM for MFC applications.

Role and Important Properties of a Membrane with Its Recent Advancement in a Microbial Fuel Cell

Microbial fuel cells (MFC) are an emerging technology for wastewater treatment that utilizes the metabolism of microorganisms to generate electricity from the organic matter present in water directly. The principle of MFC is the same as hydrogen fuel cell and has three main components (i.e., anode, cathode, and proton exchange membrane). The membrane separates the anode and cathode chambers and keeps the anaerobic and aerobic conditions in the two chambers, respectively. This review paper describes the state-of-the-art membrane materials particularly suited for MFC and discusses the recent development to obtain robust, sustainable, and cost-effective membranes. Nafion 117, Flemion, and Hyflon are the typical commercially available membranes used in MFC. Use of non-fluorinated polymeric membrane materials such as sulfonated silicon dioxide (S-SiO2) in sulfonated polystyrene ethylene butylene polystyrene (SSEBS), sulfonated polyether ether ketone (SPEEK) and graphene oxide sulfonated polyether ether ketone (GO/SPEEK) membranes showed promising output and proved to be an alternative material to Nafion 117. There are many challenges to selecting a suitable membrane for a scaled-up MFC system so that the technology become technically and economically viable.

Design and development of biomimetic electrospun sulphonated polyether ether ketone nanofibrous scaffold for bone tissue regeneration applications: in vitro and in vivo study

Bone defect restoration remains challenging in orthopedic medical practices. In this study an attempt is carried out to probe the use of new biomimetic SPEEK (sulfonated polyether ether ketone) based nanofibrous scaffold to deliver amine functionalized hydroxyapatite nanoparticles loaded resveratrol for its potent functionality in osteogenic differentiation. SPEEK polymer with reactive functional group SO3H was synthesized through process of sulphonation reaction. Amine functionalized nanoparticles with protonated amino groups revamp the molecular interaction by the formation of hydrogen bonds that in turn intensify the bioactivity of the nanofibrous scaffold. Osteoconductive functionalized nanohydroxyapatite enhances the cell proliferation and osteogenicity with improved cell attachment and spreading. The results of FT-IR, XRD, Carbon-Silica NMR and EDX analysis confirmed the amine functionalization of the hydroxyapatite nanoparticles. Surface morphological analysis of the fabricated nanofibers through SEM and AFM analysis shows vastly interconnected porous structure that mimics the bone extracellular matrix, which enhances the cell compatibility. Cell adhesion and live dead assay of the nanoscaffolds express less cytotoxicity. Mineralization and alkaline phosphatase assay establish the osteogenic differentiation of the nanofibrous scaffold. The in vitro biocompatibility studies reveal that the fabricated scaffold was osteo-compatible with MG63 cell lines. Hemocompatibility study further proved that the designed biomimetic nanofibrous scaffold was highly suitable for bone tissue engineering. The results of in vivo analysis in zebrafish model for the fabricated nanofibers demonstrated significant increase in the caudal fin regeneration indicating mineralization of osteoblast. Thus, the commending results obtained instigate the potentiality of the composite nanofibrous scaffold as an effective biomimetic substrate for bone tissue regeneration.

Cost-Effective Membrane and Advanced Electrode for Stable Polysulfide-Ferricyanide Flow Battery

Based on inexpensive, safe, and environmentally friendly active redox species, neutral polysulfide-ferrocyanide redox flow batteries (PFRFBs) have attracted much attention for large-scale energy storage. However, the development of PFRFBs is undermined by the expensive commercial membrane materials as well as the sluggish polysulfide redox reactions. This work attempts to solve these critical problems by combining the economical membrane with the highly catalytic electrode. In specific, K + -exchanged sulfonated polyether ether ketone (SPEEK-K) membranes have been investigated in PFRFBs to replace the costly Nafion membrane. SPEEK-K with optimized degree of sulfonation enables the PFRFB high average coulombic efficiency of 99.80% and superior energy efficiency of 90.42% at a current density of 20 mA cm -2 . Meanwhile, to overcome the kinetic limitations of polysulfide redox reactions, a CuS-modified carbon felt electrode is demonstrated with excellent catalytic performance, enabling the PFRFB higher and more stable energy efficiency over cycling. The combination of the cost-effective membrane with the catalytic electrode in one cell leads to a capacity retention of 99.54% after 1180 cycles and an outstanding power density (up to 223 mW cm -2 ). The significant enhancements of electrochemical performance at reduced capital cost will make the PFRFB more promising for large-scale energy storage systems.

Icariin-loaded sulfonated polyetheretherketone with osteogenesis promotion and osteoclastogenesis inhibition properties via immunomodulation for advanced osseointegration.

Preventing prosthesis loosening due to insufficient osseointegration is critical for patients with osteoporosis. Endowing implants with immunomodulatory function can effectively enhance osseointegration. In this work, we loaded icariin (ICA) onto 3D porous sulfonated PEEK (SPEEK) via polydopamine (PDA) modification. Modified ICA-PDA@SPEEK not only promoted the polarization of macrophages to the anti-inflammatory M2 type, but also enhanced the osteogenesis of bone mesenchymal stem cells (BMSCs) and inhibited RANKL-induced osteoclastogenesis by regulating cytokine from macrophages. In vivo experiments further showed that ICA-PDA@SPEEK regulated the host immune response and promoted osseointegration in ovariectomized (OVX) rats. The above results demonstrated that ICA-PDA@SPEEK could be an excellent orthopedic biomaterial with immunomodulatory properties.

Study of amine customized exfoliated BN sheets in SPEEK-PES based blend membrane for acid-base cation exchange membrane fuel cells

The cation exchange membrane is fabricated by assemble of synthetic acid–base pairs in the composite matrix. Polydopamine modified boron nitride (AH-BN) sheets are syntheses that contain the base groups (–NH2 and –NH–) and incorporated into the sulfonated poly ether ether ketone (SPEEK)-poly ether sulfone (PES) matrices for fabricate the composite membranes. The exfoliated AH-BN sheets are evenly dispersed and strongly interacted with the SPEEK via electrostatic interplay, which modify the nanophase structure and enhance the chain packing of the composite membranes. Adding of 3 wt% AH-BN into the SPEEK-PES exhibits the elevated conductivity of 79.8 mS cm−1 and power density of 131.1 mW cm−2 at 80 ⁰C under low humidification (50%RH) that is higher compared to the SPEEK (21.2 mS cm−1 and 74.2 mA cm−2). The acid–base pairs are created at SPEEK-PES and AH-BN interfaces offers continues pathway channels for the transport of protons with minimum energy barrier via Grotthuss mechanism. Besides, it shows the power density of 172 mW cm−2 at 80 ⁰C under 75%RH, which is higher than Nafion 117 (142 mW cm−2). The high residual weight of 93.34% at 170 °C and 97.12% is obtained after TGA and Fenton study. Accelerated stability test (AST) shows the excellent voltage retention about 0.05 V after the 80 h of test that confirm the excellent chemical stability from radical effect.

Functionalized carbon black modified sulfonated polyether ether ketone membrane for highly stable vanadium redox flow battery

Sulfonated polyether ether ketone (SPEEK) membranes have attracted much attention as ion exchange membranes for vanadium redox flow batteries (VRFBs) owing to their affordability and low vanadium permeability. It's noted that they suffer from poor proton conductivity at low degree of sulfonation (DS) while poor mechanical stability at high DS. Therefore, it is a challenge to balance their performance and DS. In this work, functionalized carbon black (FCB) particles with sulfonic acid substituents were prepared and used as fillers to obtain advanced SPEEK composite membranes. This kind of SPEEK/FCB composite membranes show outstanding ion selectivity, low vanadium permeability, high proton conductivity and excellent stability. The VRFB cell with the optimized SPEEK/FCB composite membrane shows high energy efficiency (94.26%, at 50 mA cm−2), low-capacity fade rate (0.052% per cycle, at 120 mA cm−2) and long cycle life.

Nanocomposite interface coupled with thickness optimization promoting water dissociation in heterogeneous bipolar membrane

AbstractBipolar membranes (BPMs) are multilayered composite film containing an interface layer sandwiched between cation exchange layer (CEL) and anion exchange layer (AEL), and are capable of dissociating water molecules under reverse bias potential. Woven fabric supported heterogeneous bipolar membranes (HBMs) were synthesized adopting layer‐by‐layer solvent casting technique. Nanocomposite layer based on sulfonated polyether ether ketone (SPEEK) and GO (graphene oxide) were applied at the interface of CEL/AEL made of cation/anion exchange resins and poly (vinyl chloride) as binder to advance water dissociation in HBMs. Thickness of monopolar layers were initially optimized without any interfacial layer. Introduction of SPEEK interface substantially lowered onset water dissociation potential, Udiss (~1.87 V) relative to the HBM without interface (~3.27 V), which got further reduced (~1.80 V) by nanocomposite (GO + SPEEK) interface. Udiss recorded with SPEEK + GO as interface was much lower than some of the recently reported homogeneous BPM. The NaOH production from NaCl (1.0 mol⋅L−1) solution in a bipolar membrane electrodialysis set up containing synthesized HBM with nanocomposite interface (SPEEK + GO) was double than that of NaOH concentration obtained with HBM having no interface, where the current density was fixed at 50.0 mA·cm−2. Careful optimization of monopolar/interface layer thickness and composition of nanocomposite interface results in developing cost effective HBMs facilitating water dissociation at lower potential.

An overview on the progress and development of modified sulfonated polyether ether ketone membranes for vanadium redox flow battery applications

Vanadium redox flow batteries (VRFB) are among the most promising approaches to efficiently store renewable energies. In such battery type, Nafion is commonly used as membrane material but suffers from high vanadium crossover and cost. These drawbacks negatively influence the widespread commercial application of VRFBs. Alternative membrane materials with high performance and low cost are thus being developed to address these shortfalls. Among those, possible materials for the VRFB membrane is sulfonated polyether ether ketone (SPEEK), which recently attracted considerable attention due to its low cost, combined with mechanical and chemical stability, and ease of preparation. This review summarizes the research activities related to the development of SPEEK-based membranes for VRFB applications and gives an overview of the properties of PEEK and its sulfonated form. A critical analysis on the challenges of SPEEK-based membranes is also discussed.

Evaluation of the Grafting Efficacy of Active Biomolecules of Phosphatidylcholine and Type I Collagen on Polyether Ether Ketone: In Vitro and In Vivo.

Biomolecule grafting on polyether ether ketone (PEEK) was used to improve cell affinity caused by surface inertness. This study demonstrated the sequence-polished (P) and sulfonated (SA) PEEK modification to make a 3D structure, active biomolecule graftings through PEEK silylation (SA/SI) and then processed with phosphatidylcholine (with silylation of SA/SI/PC; without SA/PC) and type I collagen (COL I, with silylation of SA/SI/C; without SA/C). Different modified PEEKs were implanted for 4, 8, and 12 weeks for histology. Sulfonated PEEK of SA showed the surface roughness was significantly increased; after the silylation of SA/SI, the hydrophilic nature was remarkably improved. The biomolecules were effectively grafted through silylation, and the cells showed improved attachment after 1 h. Furthermore, the SA/SI/PC group showed good in vitro mineralization. The new bone tissues were integrated into the 3D porous structures of SA/SI/PC and SA/SI/C in vivo making PEEK a potential alternative to metals in orthopedic implants.

In situ preparation of porous metal-organic frameworks ZIF-8@Ag on poly-ether-ether-ketone with synergistic antibacterial activity

Poly-ether-ether-ketone (PEEK) is a promising material in oral repair and orthopedic implantation field due to its stability and proper elastic modulus. However, the lack of simple but effective strategy to functionalize PEEK and improve its antibacterial function hinders its further biomedical application. In this study, a sulfonated 3D porous PEEK is fabricated via sulfonation treatment, and then decorated with the in situ synthesized zeolitic imidazolate framework-8 (ZIF-8), in which Ag+ ions were loaded with high loading capacity. Surface morphology, roughness, chemical composition and hydrophilicity of all the substrates were evaluated in details, suggesting Ag+ ions loaded ZIF-8 on sulfonated PEEK (SPZA) was successfully prepared. The antibacterial activity of pristine and functionalized PEEK was evaluated by inhibition zone test, spread plate assay, growth curve, and morphology of bacteria. Experimental results demonstrate that the SPZA has effectively bacteriostatic performance against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The excellent antimicrobial activity is attributed to the synergistic effect of Ag+ and Zn2+ ions released continuously from SPZA. This work provides a promising route for surface modification of PEEK and offer a potential candidate for biomedical implants.

The sulfonated polyetheretherketone with 3D structure modified by two bio-inspired methods shows osteogenic and antibacterial functions

Implant loosening and infection around the prosthesis are the most common and serious complications in orthopedics, especially in joint surgery. To fundamentally solve these two problems, the surface of polyetheretherketone (PEEK), commonly used in orthopedic implants, is modified. PEEK is sulfonated to obtain a 3D porous structure surface. Then, polydopamine is used as an intermediary to embed SrCO3 nanoparticles into the micropores on the surface of sulfonated PEEK, so that the material can stably release strontium ions. Finally, a gentamicin-silk protein coating is added on the surface of the material to make the material release gentamicin stably. Experiments conducted on the modified material show that SrCO3 nanoparticles combined with the gentamicin-silk protein sulfonated PEEK(GS-Silk@SrCO3-PDA@SPEEK) material have strong osteogenic and antibacterial abilities both in vitro and in vivo. Our findings indicate that GS-Silk@SrCO3-PDA@SPEEK may be a potential candidate for orthopedic implant. This study also provides a novel approach for the surface modification of PEEK materials.

Sulfonated poly(ether ether ketone) reinforced with polystyrene sulfonic acid functionalized micelle templated mesoporous MCM-41 for direct methanol fuel cells

A composite membrane comprising sulfonated polyether ether ketone (sPEEK) and polystyrene sulfonic acid functionalized micelle templated MCM-41 (PSSA-f-MCM-41) is realized as a potential alternative to the Nafion membrane for direct methanol fuel cells (DMFC). PSSA-f-MCM-41 incorporation in sPEEK leads to improvement in the physio-chemical properties such as ionic conductivity, methanol permeability, tensile strength, water uptake and ion exchange capacity. The methanol permeability of the composite membrane i.e. PSSA-f-MCM-41 (1.5 wt %)-sPEEK is reduced by 60% in comparison to pristine sPEEK. Moreover, the electrochemical selectivity of the aforesaid composite membrane is four times higher than sPEEK. The DMFC performance shows the peak power density of 147 mW cm−2 for the composite membrane which is higher than the pristine sPEEK and Nafion 117 membranes. Stability test for the composite membranes confirm less degradation in OCV in comparison to pristine sPEEK.

Enhancing antibacterial capability and osseointegration of polyetheretherketone (PEEK) implants by dual-functional surface modification

The overall aim of the current study is to develop a dual-functional PEEK implant to simultaneously fight off bacterial contamination and promote osseointegration by sustained release of moxifloxacin hydrochloride (MOX) and osteogenic growth peptide (OGP) from mussel-inspired polydopamine (PDA)-coated porous sulfonated PEEK (SPK) surface. Our study revealed that the MOX/OGP PDA-modified SPK (SPD-MOX/OGP) surface exhibited a durable and excellent antibacterial effect against planktonic/adherent Staphylococcus aureus and Escherichia coli in vitro. A remarkable enhancement in specific cell adhesion, proliferation and osteogenicity were observed on the SPD-MOX/OGP substrate due to the presence of OGP and PDA molecules compared to all other groups. More significantly, using the infected and non-infected rat tibia models confirmed the in vivo antimicrobial and osteogenesis abilities of SPD-MOX/OGP. Therefore, we are confident that such dual-functional PEEK surface with both antibacterial and osseointegrative capacities in this study would give a positive answer to periprosthetic joint infection-related issues.

Preparation of an Amidated Graphene Oxide/Sulfonated Poly Ether Ether Ketone (AGO/SPEEK) Modified Atmosphere Packaging for the Storage of Cherry Tomatoes.

The shelf life of cherry tomatoes is short so that new and efficient preservation techniques or procedures are required to reduce postharvest losses. This study focused on the development of a sulfonated poly ether ether ketone (SPEEK) film incorporated with amidated graphene oxide (AGO), for the storage of cherry tomatoes in modified atmosphere packaging. The mechanical properties, gas permeability, and moisture permeability were subsequently tested. The evolution of attributes related to shelf life, such as gas composition, physicochemical properties, and sensory properties were also monitored during storage trials. AGO, as an inorganic filler, increases the thermal stability and mechanical properties of SPEEK-based films, while it reduces the water absorption, swelling rate, and moisture permeability. Importantly, all the AGO/SPEEK films exhibited enhanced gas permeability and selective permeability of CO2/O2 relative to the SPEEK film. Moreover, 0.9% (w/w) AGO/SPEEK film showed an enhanced permeability coefficient of CO2, corresponding to an increase of 50.7%. It could further improve the selective coefficient of CO2/O2 to 67.1%. The results of preservation at 8 °C revealed that: 0.9% (w/w) AGO/SPEEK film was significantly effective at maintaining the quality and extending the shelf life of cherry tomatoes from 15 to 30 days, thereby suggesting the potential for applying AGO-incorporated SPEEK films for food packaging materials.

Mesoscale Simulation on the Hydrated Morphologies of SPEEK Membrane

AbstractProton transport in proton exchange membrane is considered to depend on the hydrophilic domain formed by the microphase separation between hydrophobic and hydrophilic segments of the membrane. Therefore, the study of hydrated morphologies is crucial to understand proton transport. Here, the mesoscopic structure of sulfonated polyether ether ketone (SPEEK) membrane and SPEEK/polyethersulfone (PES) blend membrane is investigated by dissipative particle dynamics (DPD) simulation. The degree of sulfonation, water content, and PES content are considered to affect proton transport. Results show that the hydrophilic particles combine with water and are separated from hydrophobic particles to form clusters of different sizes. For the SPEEK membrane, with the increase in the sulfonation degree, clusters become large and begin to connect. Compared with isolated clusters at low water content, water clusters become large with increased water content. When water content λ = 16, the cluster size is the largest. The addition of PES accelerates the phase separation in the membrane and increases the size of water clusters. When SPEEK/PES = 4:6, the cluster size is the largest and provides the best proton transport pathway.

Exosome-functionalized polyetheretherketone-based implant with immunomodulatory property for enhancing osseointegration

The host immune response effecting on biomaterials is critical to determine implant fates and bone regeneration property. Bone marrow stem cells (BMSCs) derived exosomes (Exos) contain multiple biosignal molecules and have been demonstrated to exhibit immunomodulatory functions. Herein, we develop a BMSC-derived Exos–functionalized implant to accelerate bone integration by immunoregulation. BMSC-derived Exos were reversibly incorporated on tannic acid (TA) modified sulfonated polyetheretherketone (SPEEK) via the strong interaction of TA with biomacromolecules. The slowly released Exos from SPEEK can be phagocytosed by co-cultured cells, which could efficiently improve the biocompatibilities of SPEEK. In vitro results showed the Exos loaded SPEEK promoted macrophage M2 polarization via the NF-κB pathway to enhance BMSCs osteogenic differentiation. Further in vivo rat air-pouch model and rat femoral drilling model assessment of Exos loaded SPEEK revealed efficient macrophage M2 polarization, desirable new bone formation, and satisfactory osseointegration. Thus, BMSC-derived Exos–functionalized implant exerted osteoimmunomodulation effect to promote osteogenesis.

Investigation on the sulfonated poly(ether ether ketone)/poly(amide‐imide)/barium cerate‐based nanocomposite membrane for proton exchange membrane fuel cells

The fluorinated Nafion is replaceable by the non-fluorinated clean sulfonated poly (ether ether ketone) for hydrogen-based fuel cell. The acid-base blending of PAI to clean sulfonated poly ether ether ketone (SPEEK) increased the thermal, mechanical, and oxidative properties and decreased the conductivity. It interpreted that higher stability properties appeared on the blended membrane. The loading of BaCeO3 nanoparticles in the SPEEK/poly (amide-imide) (PAI) matrices was done via solution casting process. This outcome provides improved conductivity, ion-exchange property, water uptake (WU) with controlled stability due to the good interfacial interplay among nanoparticles and polymer. The high conductivity (14.98 × 10−3 S cm−1 at 80°C) was reached by SPEEK/PAI /BaCeO3 (90/10/06 wt%) membrane (B3) measured in the electrochemical four-probe impedance spectroscopy. Its current density and power density values are 269 mA cm−2 and 66 mW cm−2, respectively. The voltage retention of the B3 membrane was maintained almost at 0.92 V and degradation of voltage after 20 hours in the durability study was about 0.01 V.

Sulfonated poly ether ether ketone (SPEEK) based composite cation exchange membranes for salt removal from brackish water

Availability of fresh water is a serious concern due water pollution in these days. Several efforts have been made for water desalination where membrane based technology is considered prominently. Here, we synthesised sulfonated poly ether ether ketone (SPEEK) based functionalized hexagonal boron nitride (SBN) composite cation exchange membranes for water desalination. The morphology of BN and presence of sulfonic acid group are confirmed by TEM analysis. Ionic conductivity for SPEEK membrane is found to be 2.02 × 10−2 S. cm−1, which reaches to 4.05 × 10−2 S. cm−1 for SBN-10/SPEEK composite membrane. Ion exchange capacity of the SBN-10/SPEEK composite membrane also increased by 40 % and reaches to 1.66 meq.g-1 as compared to SPEEK membrane. Incorporation of SBN in membrane matrix not only improve the ion exchange capacity and ionic conductivity as well as expand the stability of the membranes. SEM micrograph confirm the uniform distribution of SBN in SPEEK membrane matrix. The composite membranes show the better ion transport properties in term of current efficiency and power consumption during salt removal from brackish water by electrodialysis. For SBN-10/SPEEK composite membrane power consumption was 0.75 kW h.Kg-1 with 98.5 % current efficiency.

Sulfonated 2D Covalent Organic Frameworks for Efficient Proton Conduction.

Open 1D channels found in covalent organic frameworks are unique and promising to serve as pathways for proton conduction; how to develop high-rate yet stable transporting systems remains a substantial challenge. Herein, this work reports a strategy for exploring proton-conducting frameworks by engineering pore walls and installing proton-containing polymers into the pores. Amide-linked and sulfonated frameworks were synthesized from imine-linked precursors via sequentially engineering to oxidize into amide linkages and to further anchor sulfonic acid groups onto the pore walls, enabling the creation of sulfonated frameworks with high crystallinity and channel ordering. Integrating sulfonated polyether ether ketone chains into the open channels enables proton hopping to across the channels, greatly increases proton conductivity and enables a stable continuous run. These results suggest a way to explore proton-conducting COFs via systematic engineering of the wall and space of the open nanochannels.