Polymer Structure Research Articles

Modulation of starch-based film properties for encapsulation of microbial inoculant

Controlled release of beneficial microorganisms in agriculture by encapsulation in biopolymeric matrices can improve biofertilizer efficacy, but it requires the modulation of properties to ensure more efficient and predictable release patterns. This study investigated the effect of a starch-based system to protect and release Priestia megaterium (former Bacillus megaterium) processed as films modified with potential cell-protective additives (maltodextrin, cellulose, and bentonite). The release kinetics, physicochemical and morphological film characteristics, and their protection against UV (Ultraviolet) radiation and temperature were evaluated. The microorganism release was dependent of the film microstructure and composition, both in initial and extended-release rates. Maltodextrin incorporation increased cell release, while cellulose and bentonite delayed due to influences in the water uptake (swelling) and diffusion across polymer structure. Modified films protected the microorganisms against UV radiation and extreme temperatures, being the film with all additives (SMCB) the best protective formulation (100 % UVC survival) compared to starch matrix (< 20 % UVC survival after 40 min) and the one with the highest viability at higher (54 % survival at 45 °C) and lower (80 % survival at 15 °C) temperatures. These insights pave the way for targeted, efficient, and sustainable biological solutions to agricultural practices, aligning with evolving needs in modern agriculture.

Insights into the structure and polymerization mechanisms of CO molecules under pressure

High pressure technique can greatly enrich the chemistry research by innovating the traditional research paradigm. Recently, tremendous attentions have been paid to the high-pressure behavior of low-Z molecules, such as CO, CO2, N2, O2 and mixtures. These molecules tend to polymerize into extended solids at the pressure of 1−100 GPa, but the structures and polymerization mechanisms are still poorly understood. Herein, as a research model, high pressure polymerization process of carbon monoxide (CO) is studied in detail both experimentally and theoretically. The in-situ Raman spectra and angle- resolved X-ray diffraction experiments prove the successful synthesis of p-CO and its amorphous structure. The theoretical simulations reveal that two CO molecules dimerize into the ethylenedione (OCCO) diradical with spin-polarized singlet state firstly, then the OCCO diradical induces the subsequent chain elongation, ring closure and chain crosslinking reactions, leading to formation of the amorphous 3D network. The multiple basic units, hybrid coordination of C/O atoms and complex connecting styles in p-CO are revealed. Based on the polymerization mechanisms, the fundamental principles governing the character (amorphous or crystalline) of extended solids under high pressure are elucidated. Due to the small dipole moment and the head-to-tail disorder of CO molecules, it is reasonable to speculate that crystalline p-CO may exist under more rigorous conditions than 110 GPa and 2000 K, at which the isoelectronic nitrogen (N2) molecules polymerize into a single-bonded cubic form of nitrogen. Our study provides a profound insight into the polymerization mechanism and structures of low-Z CO molecules under compression, contributes to the diversified chemical researches and has a generally scientific implications for the interior dynamics of planets.

Synthesis and performance of cross-linked poly(aryl ether nitrile) anion exchange membranes with dense cations and flexible side-chain structures for water electrolysis

Anion exchange membranes (AEMs) are the core components in anion exchange membrane water electrolysis (AEMWE), which play crucial role and affect the performance of AEMWE. In this work, a series of cross-linked poly(aryl ether nitrile) anion exchange membranes (CPAEN-dDQA-x) with dense cations and flexible side-chain structures are synthesized. By introducing multiple modification elements into the polymer structure simultaneously, the ion conductivity, dimensional stability, and alkali resistance stability of the prepared AEMs are effectively improved and balanced. The representative CPAEN-dDQA-0.25 showed water absorption of only 27.6 %, swelling rate of 11.2 %, and conductivity of 115.37 mS/cm at 80°C. The IEC and conductivity retention value of CPAEN-dDQA-0.25 after in 2 M NaOH solution at 80°C for 480 h were up to 86.2 % and 82 %, respectively. Meanwhile, the current density of the water electrolysis cell based on CPAEN-dDQA-0.25 is up to 477.0 mA/cm2 in 1 M KOH and 2.2 V, and its voltage don’t has significant change after 480 h of operation at a constant current density of 500 mA/cm2.

Monomer in situ polymerization as topological sutures to achieve strong interfacial adhesion and long-term anti-mold of renewable adhesive

Integrated long-term anti-mold and high bonding capacity properties into renewable biomass adhesives hold significant importance for promoting the green and sustainable development of the wood industry, yet it remains an immense challenge. Drawing inspiration from the design of molecular suture materials, we successfully developed a series of innovative quaternary ammonium salt monomers (APM12) that polymerize in situ with glycidyl methacrylate (GMA) at the interface of bonded adherents. This process constructed molecular sutures on the molecular scale, forming a robust topological entanglement network between the adhesive and the wood substrate. Such a rational structure design allowed the modified soybean meal (SM) adhesive to present a boosted bonding strength and water resistance (2.08 and 1.05MPa). The stably riveting high-effect anti-germ platform imparted the protein adhesive with ultra-long mildew resistance of 150 days for liquid SM@GMA-APM12 adhesives, outperforming all the previously reported protein-based bio-adhesives. The implementation of the suture strategy through an in situ sutural interspersed crosslinking network provided a straightforward approach and offered a novel solution for creating renewable adhesives with multiple desirable properties. Moreover, this suture strategy can be applied to other interface strong adhesion and anti-bacterial materials comprised of polymer structure, such as hydrogel, organic coatings, and membrane, broadening its scope of applications.

Terpolymerization reactions of epoxides, CO2, and the third monomers toward sustainable CO2-based polymers with controllable chemical and physical properties.

Carbon dioxide (CO2) serves as a cheap, abundant, and renewable C1 building block for the synthesis of organic compounds and polymers. Selective and efficient CO2 fixation processes are still challenging because of the kinetic and thermodynamic stability of CO2. Among various CO2 fixation processes, the ring-opening copolymerization (ROCOP) of epoxides and CO2 gives aliphatic polycarbonates with high atom economy, although the chemical and physical properties of the resulting polycarbonates are not necessarily satisfactory. Introducing the third monomers into this ROCOP system provides new terpolymers, and the thermal, optical, mechanical or degradation properties can be added or tuned by incorporating new polymer backbones derived from the third monomers at the expense of the CO2 content. Here we review the terpolymerization reactions of epoxides, CO2, and the third monomers such as cyclic anhydrides, lactones, lactides, heteroallenes, and olefins. The development of catalysts and the control of the polymer structures are described together with the chemical and physical properties of the resulting polymers.

L-Cystine-Based Polyurethane as a Drug-Delivery Vehicle in Targeted Cancer Therapy and Biomedical Applications.

Controlled and sustained drug release is a critical aspect of drug-delivery systems (DDSs) that can be used in chemotherapy while ensuring therapy effectiveness and biosafety. Hence, polyurethane (PU) is modified using a biomolecule Cystine (CYS) for protracted drug release, aiming to enhance cancer treatment efficacy while minimizing adverse side effects in tumor patients. To confirm the formation of a polymer structure, characterization techniques such as NMR and FTIR are used, and the morphology is determined using SEM. Biocompatibility of the synthesized polymers is evaluated through cellular assessments, including MTT assay, cell adhesion, and antibacterial assay along with drug release using an anticancer drug, Paclitaxel (PTX). Notably, the incorporation of PTX in the polymer matrix results in minimal mortality (85% viable cells) rates in healthy cells (3T3), in contrast to a 56% mortality rate observed with the pure drug. While PTX shows a burst release and kills cancer cells only for the first 24 h, PU loaded with the drug shows sustained release and kills the cancer cells for 3 days. This vehicle selectively kills 59% of SiHA cells after a consecutive study of 3 days, which highlights the potential of this newly designed vehicle for effective drug delivery, particularly in anticancer treatments. Moreover, cystine's antibacterial property adds up with PU; hence, PU shows antibacterial activity against Staphylococcus aureus (MIC, 20 μg/mL) and also acts as a reductive oxygen species scavenger. Therefore, modifying PU with CYS has shown sustained release of PTX along with a selective effect on cells, underscoring its significance as a superior delivery agent and supported by a shred of convincing evidence.

On-Surface Synthesis of Ni-Porphyrin-Doped Graphene Nanoribbons

On-Surface Synthesis of Ni-Porphyrin-Doped Graphene Nanoribbons

ANALISIS EFISIENSI POMPA SENTRIFUGAL PADA DESALINASI DENGAN PROSES REVERSE OSMOSIS

This study provides information for the desalination industry in an effort to improve the performance and efficiency of desalination systems using the reverse osmosis method. By paying attention to the factors that influence the efficiency of centrifugal pumps, the provision of clean water in areas experiencing a water crisis will be better. Reverse Osmosis (RO) is a system in desalination technology that is often used to replenish fresh water supplies. RO performance depends on the quality of sea water as the raw water source. RO works by utilizing osmotic pressure. Hydrostatic pressure which is greater than osmotic pressure is used to reverse the flow, thereby producing fresh water. RO utilizes a high-pressure pump process to flow seawater through a membrane polymer structure. In RO there is a main membrane module configuration which has two functions, namely supporting the performance of the RO membrane and providing efficient fluid management. The desalination system used at PT Perusahaan Air Indonesia America (PAIA) still uses centrifugal pumps and can produce a production capacity of 600-700 m3/day, and is still in the system upgrade stage. From the calculations that have been carried out, the pump efficiency value is 59.16%.

Boosting the structure, thermal, optical and dielectric properties of a thermoplastic polymer by some nanoperovskites

Boosting the structure, thermal, optical and dielectric properties of a thermoplastic polymer by some nanoperovskites

Polymer Degradation via a Mechanochemical Gating Strategy

AbstractThe extensive use of plastics, valued for their lightweight, durability, and cost‐effectiveness, has led to severe environmental pollution, with 72% of plastic waste ending up in landfills or natural habitats. Traditional methods for plastic decomposition, including both mechanical and chemical approaches, often face challenges such as incomplete degradation and stability concerns. The innovative concept of mechanical gating presents a promising solution by incorporating mechanophores into polymer structures, enabling controlled degradation. Recent advancements have focused on utilizing mechanophores, such as cyclobutane, as "door locks" to regulate the degradation process. This perspective highlights recent progress in this field, demonstrating the potential of mechanophore‐based strategies for achieving on‐demand polymer degradation. It addresses the limitations of conventional recycling methods and explores how this approach can balance polymer stability with environmental degradability, paving the way for more sustainable plastic management solutions.Early Day Record

The role of secondary structures of peptide polymers on antimicrobial efficacy and antibiotic potentiation.

The rise of antibiotic resistance, biofilm formation, and dormant bacterial populations poses serious global health threats. Synthetic antimicrobial peptide (AMP) mimics offer promising alternatives, though the impact of secondary structures in polymeric AMP mimics on antimicrobial efficacy is underexplored. This study investigates chirality-controlled α-peptide polymers (D-PP and DL-PP), synthesized via ring-opening polymerization of allylglycine N -carboxy anhydrides and post-polymerization modification through thiol-ene click chemistry. D-PP adopts a stable helical structure under biomimetic conditions, whereas DL-PP remains random. This helical structure enhanced D-PP's antibacterial and antibiotic potentiation activities, amplifying antibiotic efficacy by 2- to 256-fold across various classes-including tetracyclines, ansamycins, fusidanes, macrolides, cephalosporins, and monobactams-against multidrug-resistant Gram-negative pathogens, while maintaining low hemolytic activity and high protease stability. Mechanistic investigations revealed that D-PP exhibited greater membrane interaction. D-PP and antibiotic combinations eradicated dormant bacterial populations and disrupted biofilms with minimal antimicrobial resistance development. This study paves the way for the rational design of polypeptide-based antimicrobial agents, harnessing chirality and secondary structural features to enhance the efficacy of synthetic antimicrobial peptide mimics.

The mechanical response of polymeric gyroid structures in an optimised orthotic insole.

This study aims to explore the mechanical behaviour of polymeric gyroid structures under compression within the context of orthotic insoles, focussing on custom optimisation for lower peak plantar pressures. This research evaluates the compressive response of gyroid structures using a combination of experimental testing and numerical modelling. Stereolithography was used to manufacture gyroid samples for experimental tests, and explicit finite element analysis was used to model the gyroid's response numerically. Hyperfoam, first-order polynomial, and second-order polynomial hyperelastic constitutive models were considered to homogenise the mechanical response of the structure. The homogenised properties of the structure were then implemented in an optimisation algorithm to obtain the optimal gyroid structure for a given subject by minimising the standard distribution of plantar pressures. Findings indicate that the compressive response polymeric gyroid structures can be represented with a homogeneous material. The hyperfoam model was chosen due to its accuracy and interpolation quality. The optimisation process successfully identified configurations that maximise the mechanical advantages of gyroid lattices, demonstrating significant improvements in plantar pressure distributions. The optimised insole showed a 30% reduction in the standard deviation of the plantar pressure and a 10% reduction in the peak stress. The optimisation method reduced peak pressures by 12.2 kPa compared to a traditional medium-density Poron orthotic insole, and 94.3 kPa compared barefoot conditions. The mechanical response of gyroid structures has successfully been modelled, analysed and homogenised. The study concludes that custom gyroid-based orthotic insoles offer a promising solution for personalised foot care.

1D, 2D, and 3D Micropatterning of ZnO Nanoparticles and Nanorod by Two‐Photon Polymerization and Surface Functionalization

AbstractIn this paper, a novel method is proposed for selective deposition of ZnO nanoparticles (NPs) and growth of ZnO Nanorods (NRs) on multi‐dimensional patterned polymer surfaces. The method involves microfabrication of functionalized 1D, 2D, and 3D polymer structures by two‐photon polymerization (TPP) followed by selective assembly of ZnO NPs acting as seeds before growing ZnO NRs by chemical bath deposition (CBD) technique at low temperature. The immobilization of the ZnO NPs seed layer is done by electrostatic interaction between the positively charged polymer surface functionalized by amine groups and the negatively charged ZnO NPs functionalized by citrate molecules. The influence of citrate molecules on the stability of the ZnO NPs dispersions and their immobilization on the polymer surface is demonstrated. Spatially controlled and selective growth of ZnO NRs is shown at low temperatures on multi‐dimensional structures up to 9 mm2 and having different shapes, including 1D polymer lines, 2D microplates, and 3D arrays of cones. The diameter of NRs and their orientation can be controlled through the size of ZnO NPs and the shape of the polymer structure respectively.

High‐Potential and Stable Organic Cathode for Rechargeable Batteries with Fast‐Charging and Wide‐Temperature Adaptability

AbstractOrganic carbonyl compounds have been recognized as promising electrodes due to multiple active sites, abundant element resources and flexible structural designability, while their practical applications are still hindered by the easy solubility and low discharge potential. Herein, a novel bipolar polymer composite (TAC) was well‐designed by grafting p‐type triphenylamine units onto n‐type anthraquinone to form an extended π‐conjugated structure and in situ growing on carbon nanotubes, which was proved not only with higher discharge potential but also effectively suppress the dissolution issues. Moreover, TAC combined the advantages of different active sites and behaved a dual‐ion storage mechanism. Benefitting from the in situ polymerization process, TAC with tube‐type core–shell structure exhibited enhanced electron transport and improved utilization of active sites, resulting in high capacity (193 mAh g−1), outstanding rate performance (fast charging within 17 s), long‐term stability (a high capacity retention of 87 % after 1000 cycles) and high mass loading (10 mg cm−2). Additionally, TAC can well adapt to the temperature change, outputting a capacity of 72 mAh g−1 at −60 °C and 165 mAh g−1 at 80 °C. Such versatile polymer structure inspires the design of high performance organic materials for rechargeable batteries to satisfy high stability and wide temperature operations.

Rare Earth 4‐Hydroxyphenylacetate Complexes: Synthesis, Structural Characterization, and Corrosion Inhibition Properties#

Four different structural types of rare earth aqua 4‐hydroxyphenylacetate complexes {[Ce(L)3(H2O)2]⋅H2O}n (a), {[RE2(L)6(H2O)]⋅4H2O]}n (RE = Nd (b), Gd (c)), {[RE2(L)6(H2O)]⋅3H2O]}n (RE = Dy (d), Y (e)), {[RE2(L)6(H2O)]⋅5H2O]}n (RE = Er (f), Yb (g)), (L = 4‐hydroxyphenylacetate) have been synthesized by the metathesis reactions of corresponding rare earth metals chlorides or nitrates and sodium 4‐hydroxyphenylacetate (NaL). All compounds were obtained as 1‐D polymeric structures, with a common carboxylate coordination mode of chelating bridging. The structure of a differs in being a monometallic repeating unit and having two coordinated waters whilst the others have binuclear repeating units that resulted from the alternating coordination of one water molecule along the chain. Corrosion tests by the weight loss method and potentiodynamic polarisation tests revealed that {[Gd2(L)6(H2O)]⋅4H2O}n has the best corrosion inhibition properties for mild steel in 0.01 M NaCl. Furthermore, all a‐g complexes are more effective corrosion inhibitors than both the aqua and 2,2’‐bipyridine (bpy) complexes of unsubstituted phenylacetate indicating that 4‐OH substitution of phenylacetate enhances anti‐corrosion properties.

Architecture of a pentameric assembly of the tail tube protein in SPR phages

Abstract The majority of phages, viruses that infect prokaryotes, deliver their genomic material into host cells via a tail structure. Previous research has established that the central tube of these phages, composed of tail tube protein (TTP), is structurally conserved, typically forming either hexameric or trimeric rings. In this study, we revealed a novel pentameric assembly of TTP and present two cryo-EM structures at resolutions of 3.5 Å and 3.7 Å, respectively. Our detailed structural analysis demonstrates that the inner surface of the pentameric tube is highly negatively charged. Critical residues located on the loop between β3 and β4 play pivotal roles in the formation of the pentameric rings, and mismatches of the interactions between the stacked layers can induce the curvature of the tube. The cryo-EM structure of the TTP polymer at the tube’s end uncovered that the β-strands that span amino acids 27-65 move towards the central tunnel, potentially blocking the tunnel through which the phage genome is released. Our study provides new structural insights into a novel assembly of TTP, which will extend the understanding of phage assembly.

The deep convolution network in immersive design of digital media art in smart city

The goal of the paper is to examine how convolutional neural network (CNN) is used in the immersive world of digital media art. In order to do this, this paper first explains digital media art in the context of smart cities and the use of immersive scenarios. Next, a brief analysis of the Unet network model and deep aggregation structure is provided. Then, a projector, camera, and computer-based immersive projector-camera display system is constructed. Based on the mathematical reflection model of the system, this paper discusses the method of using CNN to solve the photometric compensation of the projection picture. Meanwhile, a Projection Compensation Network (PCN) is designed, and a multi-scale perceptual loss is added to this compensation network, and the content information of the compensated image is improved by calculating the loss of feature maps of different scales. The final network is named Perceptual Loss-Projection Compensation Network (PL-PCN). Experiments are used to confirm the PL-PCN model’s efficacy. The outcomes demonstrate that the SSIM and PSNR of the projected picture compensated by PL-PCN are boosted by 35.8% and 31.6%, respectively. While the RMSE is reduced by 40.9%, demonstrating an improvement in the compensated image’s quality. Additionally, utilizing a CNN makes it possible to do cross-reflection compensation. Additionally, compared to the network without deep polymerization, the PL-PCN with deep polymerization structure boosts the projected image’s SSIM and PSNR by 6% and 7.57%, respectively, and lowers the RMSE by 13.3% This demonstrates that the addition of deep polymerization structure can have a stronger compensatory effect. This paper can offer a theoretical framework for improving the immersive scene quality of digital media art.

Analysis of the anisotropic mechanical properties of structural adhesive joints with curing-induced pre-deformations

In modern lightweight construction, multi-material design has become increasingly important. An increasing number of structures are being adhered because adhesive joining technology can be used regardless of the material of the bonded partners. Owing to the dissimilar coefficients of thermal expansion, thermally induced relative displacements of the adherend occur during heat curing. Following these pre-deformations, changes in the mechanical properties of adhesive joints were observed. In this study, thick adherend shear specimens were used to induce defined relative displacements in the shear plane during the curing process. Quasi-static tests showed a directional dependence in the pre-deformation. This anisotropic behaviour was investigated in detail. Results showed that shear band formation occurred in the adhesive owing to the load during the cooling of joined structures. The restructuring of the polymer structure leads to changes in the mechanical properties.

Giant Piezoelectric Coefficient of Polyvinylidene Fluoride with Rationally Engineered Ultrafine Domains Achieved by Rapid Freezing Processing.

Domains play an essential role in determining the piezoelectric properties of polymers. The conventional method for achieving ultrafine piezoelectric domain structures for polymers is multiphase polymerization, which is not the primary choice for industrial-scale applications because of its complex synthesis and weak mechanical properties. In this study, it is demonstrated for the first time that a nanoscale domain design can be achieved in a commercially available polyvinylidene fluoride (PVDF) homopolymer through a simple fabrication method involving cyclic compression and rapid freezing. The domain-engineered PVDF exhibits largely enhanced piezoelectric output with a record-breaking piezoelectric coefficient (d33) of 191.4 picocoulombs per Newton (8.9 times higher than that of PVDF without engineered domain structure) and electromechanical coupling factor (k33) of 77.1%. Moreover, nanoscale domain-induced ferroelectric and dielectric evolutions are revealed. A smaller domain is found to be beneficial for domain switching. An in-depth understanding of the interplay between the domain structure and piezoelectric properties reveals a simple, low-cost method for fabricating high-performance polymeric piezoelectric.

Abstract 4121530: Comparison of Drug-Coated Balloon Versus Drug-Eluting Stents in Acute Myocardial Infarction Patients Undergoing Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

Background: Percutaneous coronary intervention (PCI) is the preferred revascularization strategy for acute myocardial infarction (AMI). Drug-eluting stents (DES) are linked to higher risks of stent restenosis and stent thrombosis when implanted for AMI. Drug-coated balloons (DCB) provide a high concentration of anti-proliferative drugs over the target lesion without using the polymeric stent structures. The current literature comparing DCB to DES for AMI PCI is limited. Methods: A systematic literature search was performed on the major electronic databases for studies comparing DCB to DES for AMI PCI. Mean difference (MD) and odds ratio (OR) with their corresponding 95% confidence intervals were pooled using a random-effects model, and a p-value of &lt;0.05 was considered statistically significant. Results: A total of 8 studies with 1401 AMI patients were included (545: DCB and 856: DES). The pooled analysis demonstrated that DCB was associated with significantly lower mean lumen diameter on follow-up [MD: -0.26; 95% CI: -0.47, -0.05; p=0.02] compared to DES. However, there was no statistically significant difference in mean in-stent late lumen loss [MD: 0.07; 95% CI: -0.03, 0.18], cardiovascular mortality [OR: 0.90; 95% CI: 0.35, 2.34], all-cause mortality [OR: 0.80; 95% CI: 0.25, 2.63], myocardial infarction [OR: 0.94; 95% CI: 0.36, 2.45], major adverse cardiovascular events [OR: 0.97; 95% CI: 0.47, 2.00], target lesion revascularization [OR: 1.59; 95% CI: 0.52, 4.87], and stent thrombosis [OR: 0.48; 95% CI: 0.05, 4.94]. Conclusion: In patients with AMI, PCI using DCB leads to a significant reduction in the minimum lumen diameter on follow-up compared to DES. No statistically significant difference was noted in mean in-stent late lumen loss, cardiovascular mortality, all-cause mortality, myocardial infarction, major adverse cardiovascular events, target vessel revascularization, and stent thrombosis. Further trials are warranted to confirm these findings.