Polymer Layer Research Articles

Enhancing the attraction of positively charged precursors of conductive polymer poly(3,4-ethylenedioxythiophene) by anchoring sulfonate groups in cellulose fibres

Interfacial interactions are key to the development of high-performance coatings such as conductive polymer layers on fibrous materials. In this work, we present an approach of strengthening the interaction by forming ionic bonds between cellulose fibres and the conductive polymer layer by introducing a sulfonate group on cellulose fibres. The ionic bonds are formed between anchored sulfonate group and the positively charged precursor 3,4-ethylenedioxythiophene (EDOT), followed by the deposition and polymerisation of poly(3,4-ethylenedioxythiophene):sulfate (PEDOT:SO4) on the fibrous substrate surface. The conductance of the PEDOT:SO4 coated substrate with anchored sulfonate groups coated may be 1.7 times higher compared to the conductance of the unmodified cellulose substrate depending on experimental conditions. EDX measurements confirm the presence of sulfur and a shift of zeta potential at lower pH supports the evidence of the anionic anchored groups on the fibre surface. Our study therefore provides a new way to enhance the affinity of fibrous cellulose materials towards polymer conductive coatings.

Assessing the hydromechanical control of plant growth.

Multicellular organisms grow and acquire their shapes through the differential expansion and deformation of their cells. Recent research has addressed the role of cell and tissue mechanical properties in these processes. In plants, it is believed that growth rate is a function of the mechanical stress exerted on the cell wall, the thin polymeric layer surrounding cells, involving an effective viscosity. Nevertheless, recent studies have questioned this view, suggesting that cell wall elasticity sets the growth rate or that uptake of water is limiting for plant growth. To assess these issues, we developed a microfluidic device to quantify the growth rates, elastic properties and hydraulic conductivity of individual Marchantia polymorpha plants in a controlled environment with a high throughput. We characterized the effect of osmotic treatment and abscisic acid on growth and hydromechanical properties. Overall, the instantaneous growth rate of individuals is correlated with both bulk elastic modulus and hydraulic conductivity. Our results are consistent with a framework in which the growth rate is determined primarily by the elasticity of the wall and its remodelling, and secondarily by hydraulic conductivity. Accordingly, the coupling between the chemistry of the cell wall and the hydromechanics of the cell appears as key to set growth patterns during morphogenesis.

The action of heated RC joints strengthened with a novel strategy combined CFRP and SSEMSM under a quasi-static cyclic load

The current work presents the application of a novel strategy for strengthening heated beam column (B-C) joints under a quasi-static cyclic load. This technique involves utilizing a layer of carbon fiber-reinforced polymers (CFRP) sheets with a layer of stainless-steel expanded metal sheet mesh (SSEMSM). These two layers are installed on the steel reinforcement cage inside the joint before concrete casting. Then the reinforced concrete B-C joints, after being cast and cured, were subjected to heat (i.e., 400 °C and 600 °C). The joints were divided into three groups: three joints were kept as is (i.e., reference joints; no strengthening was applied), whereas three joints were strengthened with the previously mentioned strategy. With a view to investigating the seismic behavior of RC joints, a quasi-static cyclic load was applied to the joints to simulate a seismic load. Results showed that the average maximum load capacity for upgraded joints (strengthened) increased by 30%, 19%, and 1% at ambient (i.e., 23 °C), 400 °C, and 600 °C temperatures, respectively, with respect to the reference joint (JCTA). More importantly, the experimental results reveal a significant increase in the cyclic response of strengthened joints (i.e., higher load capacity, greater displacement, higher dissipated energy, higher ductility, and slower degradation in the secant stiffness).

Experimental study on the mechanical property of carbon fiber reinforced polymer with the combined application of digital twin and reduced order algorithm

AbstractRecognizing the anisotropy of mechanical property transfer between carbon fiber reinforced polymer (CFRP) layers, a unidirectional reduced‐order model (UROM) is proposed to comprehensively express the mechanical properties of each layer. A crucial focus is on effectively analyzing the real‐time mechanical properties of CFRP specimens, particularly in accurately identifying and predicting the interlaminar mechanical states of anisotropic CFRP laminated specimens. Moreover, the multi fidelity surrogate (MFS) is employed to replace the computationally intensive model, amalgamating high‐fidelity sensor data with low‐fidelity data obtained from the UROM. The UROM MFS is used to reduce the amount of data in the same layer of CFRP laminates, while preserving the characteristics between different layers and preserving the interlaminar information of CFRP laminates. Finally, the stress prediction results of the UROM MFS and the unreduced MFS model were compared and analyzed. The real‐time response speed of the u‐ROM MFS digital twin (DT) model was increased by 658%. The UROM MFS DT model effectively captures the mechanical properties of each layer of CFRP laminates, enables quick calculation of model parameters, and provides accurate predictions.Highlights First, the interlayer mechanical property of CFRP is analyzed with the combined application of experimental data, DT model, and UROM MFS. Second, MFS is employed to merge high‐fidelity sensor data of CFPR laminate with low‐fidelity data obtained from UROM. Third, the digital twin framework for CFPR laminate with high response speed and calculation accuracy is proposed.

Improved ammonia sensitivity and broadband photodetection by using PBTTT-C14/WS2-QDs nano-heterojunction based thin film transistor

An ambient temperature broadband photo-detector and ammonia (NH3) gas sensor devices are developed with PBTTT-C14/WS2-QDs heterojunction thin film. This composite thin film of PBTTT-C14 conjugate polymer and hydrothermally synthesized WS2-QDs have been deposited by high yield and cost-effective ‘floating film transfer method’ (FTM), which works as a channel (p-type) of the thin film transistor (TFT). To determine the NH3 sensing behavior of the TFT, different concentrations of analyte (0.5–20 ppm) have been exposed on the channel of the TFT, which shows the response of ∼ 50 % at 10 ppm ammonia concentration that is significantly higher than PBTTT-C14 only TFT. This improvement is made possible by the NH3-responsive depleted layer of polymer/QDs heterojunction, which varies widely in the presence of ammonia. As a consequence, the ON/OFF ratio, carrier mobility and threshold voltage (Vth) of the device changes in a wider range. Besides, this TFT based gas sensor is also highly selective to the other interfering gases. In addition to NH3 gas sensitivity, This TFT also shows very high photosensitivity under white light illumination that enhances ‘ON’ and ‘OFF’ current of the device by ∼ 2.2 and 70 times, respectively under one sun white light illumination, whereas Vth of the device is shifted by ∼ 22 V. Besides, the device shows quite fast response/ recovery time under NH3 gas exposure and light illumination.

Functional Polymer Thin Films for Establishing an Effective Electrode Interface in Sulfide‐Based Solid‐State Batteries

AbstractSulfide solid electrolytes (SSEs) have garnered significant attention for their high ionic conductivity in the development of all‐solid‐state batteries (ASSBs). However, SSEs face challenges due to poor chemical and electrochemical stability, leading to SE decomposition at the anode, which in turn increases internal resistance and reduces cycle performance. Herein, to address this issue, thin polymer layers are applied to prevent direct contact between the SSE and anode using the initiated chemical vapor deposition process. This method facilitates the uniform coating of eight types of polymers with polar functionalities on indium (In) anodes. Half‐cell tests and X‐ray photoelectron spectroscopy analysis reveals that poly(acrylic acid) and poly((perfluorohexyl)ethyl acrylate), containing ─COOH and C─F bonds respectively, effectively stabilized the In/SSE interface. In full cells assembled with polymer‐coated In and LiNi0.8Co0.1Mn0.1O2 (NCM811), capacity retention show remarkable improvement, achieving 64.8% for In@pAA and 50.7% for In@pC6FA after 100 cycles, compared to 29.0% for bare In. This study provides insights into the interaction between polar bonds in polymers and SSEs, potentially bridging a significant knowledge gap resulting from the significant lack of research investigating the relationship between polymers, one of the primary materials commonly used in ASSBs.

Interface texturing for enhanced PEDOT:PSS/si solar cell efficiency

Solar cell heterostructures based on PEDOT:PSS/Si heterojunction with a flat and microrelief interfaces of pyramidal and inverted pyramids type, unmodified and chemically doped PEDOT:PSS films have been fabricated. The maximum efficiency of 6.14% was obtained for solar cell heterostructures with a pyramidal type interface and doped PEDOT:PSS film, which is five times higher than for structure with a flat interface. It shown that an increase in the efficiency is occurred both due to decrease in optical losses from textured Si interface and improvement of electrical parameters of the polymer layer due to chemical doping with DMSO.

Fast Processing Affects the Relaxation of Polymers: The Slow Arrhenius Process Can Probe Stress at the Molecular Level.

Polymer materials are commonly processed at rates higher than those at which their molecules spontaneously reach equilibrium conditions. The resulting nonequilibrium conformations might significantly affect the mechanical behavior and the shelf time of the final products. To understand how processing-properties relations work, we investigated the impact of spin coating, an archetypical method to fabricate thin polymer layers. By using a geometry in which nonequilibrium conformations are frozen over sufficiently long experimental times, we could identify how molecular relaxation is affected by fast preparation methods. We find that while the (α-)segmental relaxation is not affected by the rate at which films are processed, the intensity of the slow Arrhenius process (SAP), a relaxation mechanism active both above and below the glass transition, can be used as a probe of the degree of mechanical stress experienced by the material.

Biocompatible MXene-reinforced molecularly imprinted membranes for simultaneous filtration and acetaminophen capture

In this study, the fabrication of biocompatible MXene-reinforced imprinted membranes (MX-AIM) capable of selectively capturing acetaminophen (APAP) molecules during filtration was demonstrated. The incorporation of MXene into a polymeric support membrane led to an overall improvement in both mechanical integrity and surface reactivity of the resulting composite, subsequently allowing efficient deposition of a molecularly imprinted polymer (MIP) layer on its surface. The synergy between the high surface reactivities of MXenes and the MIP layer rendered more adsorption sites, leading to the capture of approximately 32 % APAP on MX-AIM from a 200 ppm drug feed solution, compared to only ∼2 % for directly imprinted membranes. Additionally, these MXene-modified membranes exhibited high cell viabilities when tested against human monocytic cells, reaching up to >190 % cell proliferation. Overall, this research offers important insights on incorporating MXene nanofillers into membrane production, with the potential to overcome the challenges associated with applying the molecular imprinting technique to enhance the functionality of polymer materials.

In Situ Polymerization Inhibiting Electron Localization in Hybrid Electrolyte for Room‐Temperature Solid‐State Lithium Metal Batteries

AbstractHybrid solid electrolytes (HSEs) have attracted much attention due to their advantages as both inorganic and organic polymer electrolytes. However, the organic/inorganic interfacial space charge layer has a great barrier to the transport of Li+ in the HSE. Here, an in situ polymerization layer is proposed on garnet‐type particles, working as the coherent region to eliminate the space charge layer at the organic/inorganic interfaces by inhibiting electron localization. The conjugate hybridization of fillers weakens the aggregation of particles, induces the dissociation of Li salt, and provides high‐throughput Li+ transport pathways at the ceramics/polymer interface. Furthermore, the continuous Li+ conduction networks are connected by the coherent region between inorganic fillers and polymer chains. The fabricated HSE exhibits a high ionic conductivity of 0.47 mS cm−1 and ion migration numbers of 0.78 at room temperature. The 3D Li//Li systematic battery assembled with the HSE delivers a high critical current density (CCD) of 2.0 mA cm−2. Meanwhile, the 4.5 V NCM811//Li batteries achieve a prolonged operation of 500 cycles at 0.5 C. The Li//LiFePO4 batteries demonstrate superior capacity retention of 96.4% at 1 C after 500 cycles.

Thermodynamics of solvent sorption by layers of carbon-chain polymers in damping rubber blankets

The paper addresses the study of the thermodynamic compatibility of carbon-chain polymer compositions of offset rubber blankets with low-molecular-weight liquids, paint solvents and care agents for rubber damping machine parts used in transport, mechanical engineering and printing industries. The Flory-Huggins parameters χ were determined by inverted gas chromatography and calculation performed using the mathematical model of sorption, and the correlation between χ obtained by these two independent methods was found. The excess thermodynamic characteristics of the studied systems G E, H E and S E were calculated to predict the compatibility of components in these systems. The relationship was found between χ that characterizes the thermodynamic quality of the solvent and the equilibrium swelling index of polymer networks.

Na+-Enriched Quinoid Polymer Layer with Fast Ion Transport for Dendrite-Free Sodium Metal Batteries with High Cyclic Stability

Na⁺-Enriched Quinoid Polymer Layer with Fast Ion Transport for Dendrite-Free Sodium Metal Batteries with High Cyclic Stability

Smart Biointerfaces via Click Chemistry-Enabled Nanopatterning of Multiple Bioligands and DNA Force Sensors.

Nanoscale biomolecular placement is crucial for advancing cellular signaling, sensor technology, and molecular interaction studies. Despite this, current methods fall short in enabling large-area nanopatterning of multiple biomolecules while minimizing nonspecific interactions. Using bioorthogonal tags at a submicron scale, we introduce a novel hole-mask colloidal lithography method for arranging up to three distinct proteins, DNA, or peptides on large, fully passivated surfaces. The surfaces are compatible with single-molecule fluorescence microscopy and microplate formats, facilitating versatile applications in cellular and single-molecule assays. We utilize fully passivated and transparent substrates devoid of metals and nanotopographical features to ensure accurate patterning and minimize nonspecific interactions. Surface patterning is achieved using bioorthogonal TCO-tetrazine (inverse electron-demand Diels-Alder, IEDDA) ligation, DBCO-azide (strain-promoted azide-alkyne cycloaddition, SPAAC) click chemistry, and biotin-avidin interactions. These are arranged on surfaces passivated with dense poly(ethylene glycol) PEG brushes crafted through the selective and stepwise removal of sacrificial metallic and polymeric layers, enabling the directed attachment of biospecific tags with nanometric precision. In a proof-of-concept experiment, DNA tension gauge tether (TGT) force sensors, conjugated to cRGD (arginylglycylaspartic acid) in nanoclusters, measured fibroblast integrin tension. This novel application enables the quantification of forces in the piconewton range, which is restricted within the nanopatterned clusters. A second demonstration of the platform to study integrin and epidermal growth factor (EGF) proximal signaling reveals clear mechanotransduction and changes in the cellular morphology. The findings illustrate the platform's potential as a powerful tool for probing complex biochemical pathways involving several molecules arranged with nanometer precision and cellular interactions at the nanoscale.

Identification of extracellular polymeric substances layer barrier in chloroquine phosphate-disturbed anammox consortia and mechanism dissection on cytotoxic behavior by computational chemistry

The over-dosing use of chloroquine phosphate (CQ) poses severe threats to human beings and ecosystem due to the high persistence and biotoxicity. The discharge of CQ into wastewater would affect the biomass activity and process stability during the biological processes, e.g., anammox. However, the response mechanism of anammox consortia to CQ remain unknown. In this study, the accurate role of extracellular polymeric substances barrier in attenuating the negative effects of CQ, and the mechanism on cytotoxic behavior were dissected by molecular spectroscopy and computational chemistry. Low concentrations (≤6.0 mg/L) of CQ hardly affected the nitrogen removal performance due to the adaptive evolution of EPS barrier and anammox bacteria. Compact protein of EPS barrier can bind more CQ (0.24 mg) by hydrogen bond and van der Waals force, among which O-H and amide II region respond CQ binding preferentially. Importantly, EPS contributes to the microbiota reshape with selectively enriching Candidatus_Kuenenia for self-protection. Furthermore, the macroscopical cytotoxic behavior was dissected at a molecular level by CQ fate/distribution and computational chemistry, suggesting that the toxicity was ascribed to attack of CQ on functional proteins of anammox bacteria with atom N17 (f–=0.1209) and C2 (f+=0.1034) as the most active electrophilic and nucleophilic sites. This work would shed the light on the fate and risk of non-antibiotics in anammox process.

Large-Area Ultrathin Metal-Organic Framework Membranes Fabricated on Flexible Polymer Supports for Gas Separations.

Ultrathin continuous metal-organic framework (MOF) membranes have the potential to achieve high gas permeance and selectivity simultaneously for otherwise difficult gas separations, but with few exceptions for zeolitic-imidazolate frameworks (ZIF) membranes, current methods cannot conveniently realize practical large-area fabrication. Here, we propose a ligand back diffusion-assisted bipolymer-directed metal ion distribution strategy for preparing large-area ultrathin MOF membranes on flexible polymeric support layers. The bipolymer directs metal ions to form a cross-linked two-dimensional (2D) network with a uniform distribution of metal ions on support layers. Ligand back diffusion controls the feed of ligand molecules available for nuclei formation, resulting in the continuous growth of large-area ultrathin MOF membranes. We report the practical fabrication of three representative defect-free MOF membranes with areas larger than 2,400 cm2 and ultrathin selective layers (50-130 nm), including ZIFs and carboxylate-linker MOFs. Among these, the ZIF-8 membrane displays high gas permeance of 3,979 GPU for C3H6, with good mixed gas selectivity (43.88 for C3H6/C3H8). To illustrate its scale-up practicality, MOF membranes were prepared and incorporated into spiral-wound membrane modules with an active area of 4,800 cm2. The ZIF-8 membrane module presents high gas permeance (3,930 GPU for C3H6) with acceptable ideal gas selectivity (37.45 for C3H6/C3H8).

Large‐Area Ultrathin Metal–Organic Framework Membranes Fabricated on Flexible Polymer Supports for Gas Separations

AbstractUltrathin continuous metal–organic framework (MOF) membranes have the potential to achieve high gas permeance and selectivity simultaneously for otherwise difficult gas separations, but with few exceptions for zeolitic‐imidazolate frameworks (ZIF) membranes, current methods cannot conveniently realize practical large‐area fabrication. Here, we propose a ligand back diffusion‐assisted bipolymer‐directed metal ion distribution strategy for preparing large‐area ultrathin MOF membranes on flexible polymeric support layers. The bipolymer directs metal ions to form a cross‐linked two‐dimensional (2D) network with a uniform distribution of metal ions on support layers. Ligand back diffusion controls the feed of ligand molecules available for nuclei formation, resulting in the continuous growth of large‐area ultrathin MOF membranes. We report the practical fabrication of three representative defect‐free MOF membranes with areas larger than 2,400 cm2 and ultrathin selective layers (50–130 nm), including ZIFs and carboxylate‐linker MOFs. Among these, the ZIF‐8 membrane displays high gas permeance of 3,979 GPU for C3H6, with good mixed gas selectivity (43.88 for C3H6/C3H8). To illustrate its scale‐up practicality, MOF membranes were prepared and incorporated into spiral‐wound membrane modules with an active area of 4,800 cm2. The ZIF‐8 membrane module presents high gas permeance (3,930 GPU for C3H6) with acceptable ideal gas selectivity (37.45 for C3H6/C3H8).

Perovskite QDs embedded in polymer as a wavelength-shifting layer for UV-sensitized silicon sensors

Detection of UV radiation is becoming increasingly important for many applications. Here we present novel UV sensor construction on the basis of standard Si detector modification. Wavelength shifting mechanism is achieved by the luminescence effect of perovskite quantum dots embedded in polymer layers. We comprehensively characterize these composite materials, various sensor modification routes and the optical properties of UV-enhanced visible sensors. Modified S1227-16 BG silicon photodiodes and S13360-1375 CS MPPC photodetectors with the enhanced UV response are successively manufactured.

Inkjet printed acrylate-urethane modified poly(3,4-ethylenedioxythiophene) flexible conductive films

Abstract Flexible electronics is a new generation of electronic devices in which electronic components are integrated into flexible substrates. It is used in the fabrication of displays, solar cells, integrated circuits, and increasingly in the fabrication of electronic skin (E-skin), which can mimic the properties of human skin by being able to follow skin movements and flexures without loss of mechanical and electrical properties. E-skin is suitable for integrating various sensors to monitor personal health. Conductive polymers are used in flexible electronics due to their electrical conductivity, low mass, and stability. However, their main disadvantage is their brittleness, which is why they don’t possess flexibility property without modification. Therefore, in this work, the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) was used as the main chain and the side branches of poly(acrylate-urethane) (PAU) were grafted onto it by atom transfer radical polymerization (ATRP) onto it, obtaining the grafted copolymer PEDOT-g-PAU. In this way, the main chain of PEDOT retains the property of electrical conductivity without losing conjugation, while the side branches of PAU have the ability to crosslink non-covalently through hydrogen bonds with PAU side branches of adjacent polymer molecules due to the presence of oxygen in their structure. The presence of hydrogen bonds allows increasing the stretchability and flexibility of the material, and they also have the ability to spontaneously renew themselves when they break due to excessive stress. Three different synthesis conditions were used to obtain polymers of different structure, which were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and measurement of electrical conductivity with a four-point probe (4PP) method. The obtained graft copolymer was prepared in the form of ink and printed on a polyurethane (PU) substrate using inkjet technique. The conductivity of the printed layer, its elongation and adhesion were investigated, while possible delamination of the printed polymer layer was also monitored. The results showed that the PEDOT-g-PAU copolymer was successfully synthesized and inkjet printing on PU film was successful. The obtained material has satisfactory electrical and mechanical properties and could be used for the integration of fully functional biosensors with further optimization of the composition.

Ultrasensitive detection of chloramphenicol in water using functionalized polymers with an aluminium organic framework

Metal-Organic Frameworks (MOFs) are extensively used as electrode material in various sensing applications due to their efficacious porous nature and tunable properties. However, pristine MOFs lack conductive attributes that hinder their wide usage in electrochemical applications. Electropolymerization of several aromatic monomers has been a widely used strategy for preparing conducting electrode materials for various sensing applications in the past decades. Herein, we report a similar approach by employing the electropolymerization method to create a functional polymer layer to enhance the sensitivity of an Aluminium Organic Framework (DUT-4) for the selective detection of Chloramphenicol (CAP) antibiotic in aqueous environment. The combined strategy using the conducting polymer layer with the porous Al MOF provides surpassing electrochemical performance for sensing CAP with regard to the very low detection limit (LOD = 39 nM) and exceptionally high sensitivity (11943 μA mM−1 cm−2). In addition, the fabricated sensor exhibited good selectivity, reproducibility and stability. The developed method was successfully evaluated in various real samples including lake water and river water for CAP detection with good recovery percentages even at lower concentrations.

Self-Polymerized Spiro-Type Interfacial Molecule toward Efficient and Stable Perovskite Solar Cells.

In the pursuit of highly efficient perovskite solar cells, spiro-OMeTAD has demonstrated recorded power conversion efficiencies (PCEs), however, the stability issue remains one of the bottlenecks constraining its commercial development. In this study, we successfully synthesize a novel self-polymerized spiro-type interfacial molecule, termed v-spiro. The linearly arranged molecule exhibits stronger intermolecular interactions and higher intrinsic hole mobility compared to spiro-OMeTAD. Importantly, the vinyl groups in v-spiro enable in situ polymerization, forming a polymeric protective layer on the perovskite film surface, which proves highly effective in suppressing moisture degradation and ion migration. Utilizing these advantages, poly-v-spiro-based device achieves an outstanding efficiency of 24.54 %, with an enhanced open-circuit voltage of 1.173 V and a fill factor of 81.11 %, owing to the reduced defect density, energy level alignment and efficient interfacial hole extraction. Furthermore, the operational stability of unencapsulated devices is significantly enhanced, maintaining initial efficiencies above 90 % even after 2000 hours under approximately 60 % humidity or 1250 hours under continuous AM 1.5G sunlight exposure. This work presents a comprehensive approach to achieving both high efficiency and long-term stability in PSCs through innovative interfacial design.