Search Results (6,940)

In the pursuit of sustainable and flexible electronics, polymer-based conductive films offer a promising solution due to their biodegradability, mechanical flexibility, and cost-effective fabrication. This study presents the development of a highly conductive and flexible nanocomposite material based on polyaniline-grafted chitosan (PANI-g-Chs) and Vinavil (Vi, a vinyl glue specifically designed for enhancing the sealability of textiles and paper), serving as a matrix for applications in flexible electronics. The PANI-g-Chs nanocomposite was synthesized via in situ oxidative polymerization, where chitosan nanoparticles (Chs) served as a stabilizing template to prevent PANI aggregation, reducing the particle size from 1700 nm (pristine PANI) to 180 nm (PANI-g-Chs). The resulting composite exhibited exceptional electrical conductivity (77.79 S/m at 25 wt% PANI-g-Chs). Hall effect measurements showed that the carrier mobility increased up to 1162.7 cm²/V·s and the carrier density rose to 6.5.1017 cm⁻³, confirming efficient charge transport and network formation. Mechanical analysis revealed a 300% increase in the storage modulus for PANI-g-Chs, and thermal studies confirmed stability up to 300 °C. Optical characterization showed a reduced bandgap (3.6 eV) and extended π-conjugation, which are critical for optoelectronic applications. Application tests demonstrated stable conductivity under mechanical deformation, highlighting the material’s potential for use in flexible electronics, sensors, and sustainable conductive coatings. This work offers a viable alternative to conventional conductive polymers. Full article

The practical application of inorganic ferroelectric fillers in flexible piezoelectric composites is critically constrained by low polarization efficiency and severe interfacial incompatibility with polymer matrices. Herein, we report a multi-level in situ surface modification strategy that simultaneously addresses both limitations. High-purity one-dimensional tetragonal barium titanate nanofibers (BTO NFs) are first synthesized via sol–gel electrospinning combined with a two-step gradient annealing process, which precisely controls phase evolution and preserves structural continuity. To overcome the detrimental acid-induced degradation of BTO NFs during functionalization, a polydopamine (PDA) buffer layer is first conformally coated, followed by the liquid-phase deposition of a conductive polypyrrole (PPy) shell, forming a robust core–shell PPy@PBT NFs architecture. Incorporating only 4 wt% of these multifunctional fillers into a poly(vinylidene fluoride) (PVDF) matrix yields a dramatic enhancement in electromechanical performance. The resulting flexible piezoelectric energy harvesters achieve a piezoelectric coefficient (d₃₃) of 28.7 pC/N, an output voltage of 13 V, and an output current of 0.7 μA, representing substantial improvements over unmodified filler systems. This synergistic enhancement originates from the PDA-mediated interfacial stress transfer and the PPy-induced Maxwell–Wagner polarization intensification, establishing a robust and generalizable paradigm for high-performance flexible piezoelectric composites in self-powered wearable electronics. Full article

Escherichia coli (E. coli) is a microorganism commonly found in water and food matrices, and its rapid and accurate detection is crucial for maintaining public health and ensuring food safety. However, traditional molecularly imprinted polymer (MIP) sensors often face challenges such as tedious template removal and prolonged sensing times. This study develops a label-free bacterial molecularly imprinted sensor that utilizes the synergistic effect of polypyrrole (PPy) and multi-walled carbon nanotubes (MWCNTs) to achieve highly sensitive detection of E. coli. Based on the large specific surface area and superior conductivity of MWCNTs, as well as the favorable electrochemical polymerization properties of PPy, a PPy/MWCNTs composite film was fabricated via a one-step electropolymerization process. The prepared sensor exhibited excellent kinetic characteristics, with a template removal time of only 15 min, and could be regenerated and used for subsequent detection within 30 min. Under optimized conditions, the biosensor showed a satisfactory linear response over the concentration range of 10²–10⁸ CFU/mL, with a low detection limit of 65 CFU/mL (3σ/S). Furthermore, recovery experiments conducted in tap water and lemon juice samples yielded satisfactory recoveries ranging from 87.1% to 114.8%, demonstrating the reliability and practical applicability of the proposed sensor for bacterial detection in real samples. This sensor offers advantages such as simple preparation, low material cost, and high sensitivity, providing a reliable and practical analytical platform for the rapid and reliable detection of bacteria. Full article

Flexible resistive bend sensors are essential for monitoring human movement in smart rehabilitation and soft robotics. However, widespread adoption is currently hindered by a trade-off between the high cost of metal-film technologies and the performance degradation (significant hysteresis and non-linearity) of low-cost carbon/polymer composites. This study presents a geometrically customizable bending sensor fabricated from conductive thermoplastic polyurethane (TPU) using Fused Deposition Modeling (FDM) technology as an accessible alternative to commercial sensors. By parametrically optimizing physical dimensions—including trace width, layer thickness, and pattern geometry—the sensors were tailored to achieve target resistance values within a target window of 20–50 kΩ (achieved: ~44 kΩ nominal) for specific finger-joint applications. Electromechanical characterization revealed a negative gauge factor (GF), where resistance decreases upon bending or elongation due to conductive pathway formation and densification within the polymer matrix. This behavior cannot affect sensor operation, and required bend-resistance responses were acquired using geometrical optimization. To compensate for inherent viscoelastic-induced hysteresis and non-linear behavior, a third-degree polynomial modeling approach was implemented. This modeling approach yielded a coefficient of determination (R²) of approximately 0.90. Compared to standard commercial sensors, the proposed FDM-printed design successfully overcomes geometric limitations while offering a cost-effective, high-performance solution for tailor-made wearable technologies and smart rehabilitation gloves. Full article

The development of reliable electrochemical interfaces for biosensor applications requires materials that combine high conductivity, large effective surface area, and suitable platforms for biomolecule immobilization. In this work, a hybrid electrochemical platform based on screen-printed carbon electrodes (SPCEs) modified with electropolymerized polypyrrole (PPy) and electrodeposited silver particles (AgPs) is presented for the subsequent immobilization of Ki-67 antibodies. PPy films were synthesized under optimized electrochemical conditions, producing homogeneous, porous, and electrochemically stable coatings that significantly enhanced the doping/undoping processes from 0.3280 C/0.3284 C to 0.3281 C/0.3284 C for SPCE and SPCE-PPy, respectively. Subsequently, silver particles were deposited onto the PPy matrix, resulting in a well-dispersed and uniform distribution of AgPs, promoted by the interaction between Ag⁰ and the nitrogen groups in the polymer backbone. The synergistic combination of PPy and AgPs resulted in improved charge-transfer properties and enhanced electrochemical reversibility, thereby decreasing the peak-to-peak separation of the ferricyanide/ferrocyanide redox couple used as a probe by 40%. Immobilization of Ki-67 antibodies was achieved via direct interaction with AgPs, resulting in a marked passivation effect, as evidenced by the suppression of redox probe signals, confirming successful biofunctionalization. The proposed SPCE-PPy-AgP architecture provides a robust, reproducible, and versatile platform for antibody immobilization, as demonstrated by oxidation and reduction peaks with relative standard deviations (RSDs) of 3.18% and 4.43%, respectively, highlighting its potential for developing label-free electrochemical immunosensors for clinically relevant proliferation biomarkers. Full article

Advanced thermal management applications, including electronics cooling, battery systems, and micro heat exchangers, are increasingly requiring thermally conductive yet flexible polymer composites. Composite films containing total nanofiller loadings of 2.5, 5, 7.5, and 10 wt.% were systematically characterized using SEM, TGA, DSC, TT, and SSTM following ASTM C177-19. SEM analysis confirmed uniform dispersion and effective network formation of MWCNTs and GNPs within the TPU matrix at higher filler loadings. Thermal stability improved significantly, with the degradation onset temperature increasing from 319.2 °C for pure TPU to 369 °C for the TPU/MWCNT/GNP (90/5/5 wt.%) composite. DSC results revealed enhanced glass transition and melting temperatures, indicating improved thermal resistance and crystallinity. Mechanical testing showed a substantial increase in Young’s modulus, reaching 72.5 MPa for the 90/5/5 wt.% composite, corresponding to a 286.66% improvement over pure TPU. Most notably, steady-state thermal conductivity increased dramatically from 0.20 W/mK for pure TPU to 1.533 W/mK for the 90/5/5 wt.% composite, representing a 666.50% enhancement. The experimental results closely aligned with percolation-based theoretical models at higher filler concentrations. Overall, the developed hybrid nanofiller TPU composites demonstrate a synergistic improvement in thermal conductivity, mechanical strength, and thermal stability, making them promising candidates for flexible thermal management components in electronics, automotive, renewable energy, and biomedical applications. Full article

Injection molding process optimization has predominantly relied on simulation-generated data, which cannot capture machine-specific variability and stochastic process noise inherent in real manufacturing environments. This paper presents an experiment-driven machine learning framework for multi-objective optimization of injection molding process parameters targeting volumetric shrinkage, warpage, cycle time, and part weight. Physical experiments were conducted on an industrial injection molding machine using high-density polyethylene with a face-centered central composite design. Systematic benchmarking of four machine learning algorithms under identical cross-validation protocols identified Gaussian process regression as the best-performing surrogate model for the majority of quality metrics, while warpage prediction remained challenging across all algorithms due to its complex thermo-mechanical origins. Permutation-based feature importance analysis established a clear parameter hierarchy, identifying holding time as the dominant factor governing multiple quality responses. Constrained Bayesian optimization with progressive constraint tightening was employed to identify optimal parameter sets and fundamental process capability boundaries. The resulting parameter configurations were validated against a held-out test set. This work demonstrates that rigorous, data-driven optimization using exclusively experimental data provides a viable and practically achievable alternative to simulation-based approaches, contributing to experiment-centric smart manufacturing in polymer processing. Full article

This study systematically investigates the formulation–property relationships of epoxy-based silver conductive adhesives by varying silver filler architecture, total filler loading, and organic carrier design. Rotational viscometry, four-point probe measurements, thermal conductivity analysis, and scanning electron microscopy (SEM) were employed to elucidate the correlations among rheological behavior, conductive network formation, and electrical–thermal transport properties. All formulations incorporate dicyandiamide (DICY) as a latent curing agent, in combination with a thermally activated accelerator and silane coupling agents, to stabilize filler–matrix interfaces and suppress moisture-assisted side reactions. This latent curing chemistry enables effective low temperature curing at approximately 155 °C, providing compatibility with temperature-sensitive flexible polymer substrates. After sealed storage at 25 °C and 60% relative humidity for two weeks, all formulations exhibited viscosity variations within ≤16%, demonstrating extended pot life and good storage stability under ambient conditions. Meanwhile, the normalized volume resistivity and thermal conductivity remained close to their initial values, with maximum relative deviations of approximately 12% and 7%, respectively, from the initial (Day 0) values across all formulations, indicating stable electrical and thermal transport properties during storage. Differences in conductive network formation and filler packing characteristics were reflected in the observed electrical and thermal transport behaviors. Balanced electrical–thermal performance was achieved without the need for high-temperature sintering or post-annealing, underscoring the effectiveness of the low temperature curing strategy. Overall, this work defines a practical formulation design window that simultaneously achieves low temperature curability, long pot life, stable rheology, and robust electrical–thermal performance. The results provide useful material-level guidelines for the development of epoxy-based silver conductive adhesives intended for conductive interconnects on flexible polymer substrates and related flexible electronic applications. Full article

Polyhydroxyalkanoates (PHAs) emerge as promising biodegradable polymers for sustainable applications, yet predicting their biodegradation behavior under different environmental conditions remains challenging. In this study, we propose a novel data-driven computational framework for predicting biodegradation-induced weight/mass loss in PHA-based materials. A comprehensive database of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-based formulations was manually curated by systematically collecting and harmonizing material descriptors, environmental parameters, and experimental biodegradation outcomes from laboratory- and large-scale studies conducted in soil, marine, freshwater, and compost environments. Multiple regression-based quantitative structure–activity relationship (QSAR) models were developed and rigorously validated, demonstrating high predictive performance and strong correlations between polymer structure, environmental conditions and degradation behavior. “Exposure time”, “degradation environment” and “hydroxybutyrate (HB) ratio” were identified as the most important features for weight loss. Finally, the predictive model was integrated into the Jaqpot computational platform, enabling open access and facilitating data-driven assessment and design of biodegradable polymer systems. Full article

Background: The ability of synthetic plastics to persist in the environment and the accumulation of microplastics has intensified the need to explore biological mechanisms capable of interacting with, and possibly degrading, polymeric materials. Microbial enzymes that have extensive catalytic flexibility represent promising candidates in this context. Aim: This study set out to examine the molecular interaction patterns and dynamical stability of Pseudomonas aeruginosa elastase (LasB) with representative structural fragments of typical synthetic plastics to assess the suitability of the enzyme to polymer-derived substrates. Methods: The crystallographic structure of LasB (PDB ID: 1EZM) was retrieved from the Protein Data Bank and pre-prepared with the help of AutoDock4.2.6 Tools. Those polymer-derived ligands that were associated with the major industrial plastics such as polyamide (PA), polyvinyl chloride (PVC), polycarbonate (PC), poly-ethylene terephthalate (PET), polymethyl methacrylate (PMMA), and polyurethane (PUR) were retrieved in the PubChem database and geometrically optimized with the help of the MMFF94 force field. AutoDock Vina, with a specific grid box around the catalytic pocket, including Zn²⁺ ion, was used to perform molecular docking simulations. PyMOL and BIOVIA Discovery Studio software were used to analyze binding conformations, interaction residues and types of intermolecular contacts. Phosphoramidon, a known metalloprotease inhibitor, served as a positive control to confirm the docking protocol. Additional assessment of the structural stability and conformational behavior of the enzyme–ligand complexes was conducted by molecular dynamics (MD) simulations with the Desmond engine and explicit solvent model in a 50 ns trajectory using the OPLS4 force field. RMSD, RMSF, radius of gyration, hydrogen bonding analysis and solvent accessibility parameters were used to measure structural stability. Results: The docking experiment showed varying binding affinities with the test polymers. Polycarbonate (−5.774 kcal/mol) and polyurethane (−5.707 kcal/mol) had the highest in-teractions with the LasB catalytic pocket, polyamide (−5.277 kcal/mol) and PET (−4.483 kcal/mol) followed PMMA and PVC, which had weaker affinities. The following were the important residues involved in interaction networks: Glu141, His140, Val137, Arg198, Tyr114, and Trp115 that were implicated in interaction networks with hydrophobic interactions, π-cation interactions and van der Waals forces that were the major stabilization forces. MD simulations had stabilized complexes, and RMSD values were found to be within acceptable ranges of stability, and ligand-specific changes (around 1.0-3.2 A), which is also in line with stable protein-ligand systems. Phosphoramidon used as a positive control had an RMSD of 1.205 A which is within this stability range. PCA determined various ligand-bound conformational states of LasB with PA in com-pact state, PC and PVC in intermediate states and PUR, PMMA and PET in ex-panded conformations, indicating structur-al stability and adaptability of the binding pocket. Conclusion: These findings show that LasB has a structurally flexible catalytic pocket that can accommodate a wide range of polymer-derived ligands. These results offer an insight into the recognition of enzymes with polymers at the molecular level and also indicate that LasB might help in the interaction of microorganisms with synthetic plastics in environmental systems. Full article

Background/Objectives: Implant-associated infections remain among the most severe and clinically challenging complications in contemporary orthopedics, largely due to the formation of persistent bacterial biofilms and the limited penetration of systemically administered antibiotics into the tissue–implant interface. In this context, local antibacterial functionalization of implantable materials represents a promising strategy for the prevention of early infectious complications. The objective of this study was to develop and comparatively evaluate the antimicrobial performance of PLA-based composites loaded with antibiotics from different pharmacological classes, with a view toward their potential application in individualized 3D-printed implants. Methods: Polylactic acid (PLA)-based composites incorporating gentamicin, ciprofloxacin, doxycycline, and vancomycin were fabricated using thermal processing under conditions compatible with extrusion and fused filament fabrication. Physicochemical characterization (FTIR, TGA, SEM) was performed to assess the structure and morphology of the composites, and in vitro antibiotic release studies were conducted. Antimicrobial activity was evaluated using an agar diffusion assay against ATCC reference strains and clinical isolates of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA), Klebsiella pneumoniae, and Pseudomonas aeruginosa (n = 10 per species). The antibacterial performance of the composites was evaluated in comparison with standard commercial antibiotic disks used as qualitative reference controls. Results: Antibiotic-loaded PLA composites exhibited consistent and reproducible antibacterial activity, markedly exceeding that of neat PLA. The broadest activity spectrum was observed for PLA–ciprofloxacin (≈29–36 mm) and PLA–gentamicin (≈25–27 mm), which effectively inhibited both Gram-positive and Gram-negative clinical isolates, including MRSA and P. aeruginosa. PLA–vancomycin retained selective activity against staphylococci (≈14–15 mm), whereas PLA–doxycycline demonstrated limited efficacy against Gram-negative pathogens. Physicochemical analysis confirmed successful incorporation of antibiotics without detectable degradation of the polymer structure, while release studies demonstrated sustained antibiotic release from the composite materials. Importantly, the expected pharmacological activity profiles of the antibiotics were preserved after incorporation into the polymer matrix and subsequent high-temperature processing. Conclusions: The results demonstrate the feasibility of integrating clinically relevant antibiotics into a thermoplastic PLA matrix while preserving their selective antimicrobial activity following processing compatible with extrusion and additive manufacturing. The proposed PLA-based composites can be regarded as elements of a pharmacologically tunable antibacterial platform, offering a rationale for the development of context-dependent, biodegradable, 3D-printed implants for the local prevention of implant-associated infections in the setting of increasing antimicrobial resistance. Full article

Glass-Fiber-Reinforced Polymer (GFRP) bars are emerging as an alternative to steel reinforcement in concrete structures thanks to their high mechanical performance and intrinsic resistance to corrosion. Nevertheless, their actual sustainability must be verified through an assessment that considers long-term durability, life cycle environmental impacts, and economic feasibility. The replacement of steel reinforcement with GFRP in concrete bridge decks is herein evaluated through an integrated methodology. First, a comprehensive literature review examines the degradation processes observed experimentally and the associated long-term evolution of mechanical properties, providing the basis for defining realistic durability scenarios. Subsequently, a comparative Life Cycle Assessment is conducted adopting a cradle-to-grave system boundary and using Environmental Product Declarations to build the Life Cycle Inventory and perform the Impact Assessment. Normalization and weighting phases are included for a better understanding of the overall impacts of the two alternatives. In parallel, a Cost Analysis is performed consistently with the system boundaries and scenarios considered in the Life Cycle Assessment. Finally, the Envision protocol, a framework to evaluate sustainability and resilience of infrastructures, is applied to identify credits directly influenced by the adoption of GFRP reinforcement. The results show that steel reinforcement exhibits lower initial environmental impacts and remains more economical over short service life horizons. However, if the extended durability of GFRP is considered, the reduction in heavy maintenance activities allows this solution to achieve superior environmental performance and improved economic balance. The Envision-based evaluation further confirms the potential contribution of GFRP reinforcement to higher sustainability ratings in infrastructure projects. Full article

Polymer-based biosensors have evolved from passive supports into active functional elements that dictate analytical performance in complex real-world samples. This critical review with meta-trend analysis examines 96 original research articles published between 2015 and 2025, evaluating how four polymer classes (conductive polymers, redox-mediator polymers, hydrogels, and molecularly imprinted polymers) address matrix effects in food, beverage, environmental and clinical applications. Electrochemical detection dominates (79% of studies), with conductive polymers enabling low-potential operation that excludes electroactive interference. Hydrogels achieve superior precision (RSD below 3%) in protein-rich matrices through biocompatible microenvironments that preserve enzyme kinetics. Molecularly imprinted polymers provide unmatched stability in harsh environments for trace-level detection of heavy metals and toxins, though delayed response times from slow analyte diffusion persist. Critical evaluation exposes validation deficits: 91% of studies omit limits of quantification, while approximately one-third lack reproducibility (33%) and precision (30%). The multi-matrix challenge, maintaining calibration across different hostile environments, remains the primary barrier to commercial deployment. Advanced architectures, including nanocapsulation, hierarchical nanocomposites, and microneedle-integrated systems, offer pathways to overcome limitations in fouling resistance and operational stability. Full article

Microplastics (MPs) are synthetic polymer particles that are generally less than 5 mm in size and have attracted heightened scrutiny due to their pervasive presence in the environment, along with their toxicological significance. Several research investigations documented its presence in humans as a profound finding in biological tissues and fluids crossing barriers, leading to oxidative and inflammatory pathways alterations associated with blood, placenta, cardiovascular, pulmonary, nephrotic, other systems, and their disorders. Given the ubiquitous utilization of microplastics across diverse sectors, it is imperative to systematically investigate and elucidate their potential toxicological effects on biological systems through rigorous and mechanistically informed research. This review will also provide the synthesis of recent mechanistic data on the toxicity that can be caused by MPs and will determine key gaps that impede efficient human health risk evaluation. A structured literature search was conducted via PubMed, Web of Science, and Scopus databases, mostly from the studies published between 2010 and 2026. The studies of exposure characteristics and biological effects were analyzed in vitro, in vivo, and in human biomonitoring, and the primary focus of the interventions includes oxidative stress, inflammation, apoptosis, hepatotoxicity, and metabolic malfunction. MPs possess various physicochemical properties, such as a low particle size, various shapes, surface area, polymer composition, and the presence of sorbed or intrinsic additives. When MPs are taken up by cells, they can induce oxidative stress via increasing ROS, eventually leading to high lipid peroxidation, mitochondrial malfunction, DNA fragmentation, and eventually cell death. MPs also cause pro-inflammatory cytokine responses, including TNF-α, IL-1β, and IL-6, altering the immune system and cell profile, leading to systemic inflammation. In aquatic and terrestrial organisms, these microplastics have a harmful impact on growth, reproduction, and behavior in a time- and dose-dependent manner. Under conditions of controlled exposure, the organ-specific toxicities that have been reported include hepatic, renal, neurological, reproductive, and cardiovascular systems. Although the fields of mechanistic knowledge are growing, there is still a substantial amount of uncertainty; there is a lack of characterization of the long-term effects of low-dose chronic exposure, the kinetics of bioaccumulation, biodegradation potential, and transgenerational effects. In addition, there are no standardized procedures for the characterization of MPs, nor the reporting of the distribution of size or exposure measurements, which limits the comparability of cross-studies and makes it difficult to assess risks quantitatively. The dynamics of interactions of MPs between co-adsorbed contaminants like heavy metals, polycyclic aromatic hydrocarbons, and endocrine-disrupting chemicals are also yet to be explored. Although all evidence available to date does indicate biologically plausible mechanisms of MP-induced toxicity, integrated research employing standardized analytical protocols, an environmentally relevant exposure model, and human epidemiological data is required to ensure that laboratory results are translated into evidence-based public health and regulatory actions. This review offers an in-depth analysis of the existing molecular understanding of MP-induced toxicity, demonstrates organism-level impacts throughout species, and establishes vital fields for future studies. In order to develop competent guidelines to minimize MP exposure and its adverse health effects, it is crucial to cover these gaps via research that incorporates toxicology and environmental science. Full article

Developing efficient and durable electrocatalysts for the alkaline hydrogen evolution reaction (HER) remains challenging due to intrinsically sluggish reaction kinetics and the limited long-term stability of many non-noble metal catalysts under continuous operation. Herein, a nickel-doped polypyrrole/chitosan composite electrode on stainless steel (PPy/Chi/Ni) was fabricated via electrodeposition as a low-cost and scalable method. Benefiting from the combined effects of Ni incorporation and the conductive polymer–biopolymer composite framework, the optimized PPy/Chi/Ni electrode exhibits enhanced HER activity in alkaline environment, delivering a low overpotential of η₁₀ = 78 mV at a current density of 10 mA·cm⁻² and a reduced Tafel slope of 93 mV·dec⁻¹, indicative of accelerated reaction kinetics. Structural and morphological characterizations by XRD, FTIR, and FESEM indicate the formation of the composite structure. FESEM images suggest that the deposited layer forms a relatively uniform coating on the stainless steel substrate. EIS further reveals improved interfacial charge-transfer characteristics upon Ni doping. Additionally, long-term stability tests confirm the structural integrity of the composite electrode and its electrochemical stability under HER conditions by demonstrating stable HER performance for 15 h with only a 22 mV potential change at a constant current density. By providing a conductive interface and numerous catalytic sites, the Ni-doped electrocatalyst coating activates the stainless steel substrate, leading to a 79% reduction in overpotential compared to bare stainless steel and thereby significantly improving its HER performance. Full article