Polymer Functional Groups Research Articles

Bi-Functional Interfacial Modification Enables Highly-Exposed Zn(002) Crystal Facet Towards Durable Zn Metal Batteries.

Zn-ion batteries (ZIBs) have garnered growing interest in large-scale energy storage devices for the high safety, high theoretical capacity and low electrochemical potential. Nevertheless, their widespread applications are significantly impeded by dendrite formation, hydrogen evolution and corrosion reactions of Zn anodes. Herein, a bi-functional polyacrylic acid (PAA) modified-Zn anode (Zn-PAA) is designed to concurrently inhibit Zn dendrite formation and alleviate side reactions for durable ZIBs. The bi-functional PAA coating not only selectively acid-etches the active Zn crystal facets to guide the planar deposition along the highly-exposed Zn(002) crystal facet, but also facilitate uniform Zn deposition through coordination between the polymer functional groups and Zn2+. Meanwhile, the electrically-insulated PAA protective layer effectively separates Zn anodes from the electrolyte and modulates the solvation structure of Zn2+.6H2O, significantly suppressing side reactions. Consequently, the assembled Zn-PAA//Zn-PAA symmetrical cell delivers an outstanding cycling stability of 1600 h at 1 mA cm-2 and 1 mAh cm-2. The assembled KVO//Zn-PAA full cell shows exceptional cycling stability over 1500 cycles at 2.0 A g-1 with a high Coulombic efficiency approaching 100 %. The facile bi-functional surface modification strategy, which enables to finely tune the crystal facet texture and ion distribution manner, opens up a groundbreaking path towards safe and durable ZIBs.

Synthesis, characterization, and surface modification of degradable polar hydrophobic ionic polyurethane nanoparticles for the delivery of therapeutics to vascular tissue

Degradable polar hydrophobic ionic polyurethanes (D-PHI) are an emerging class of biomaterials with particular significance for blood-contacting applications due to their immunomodulatory effects and highly customizable block chemistry. In this manuscript, D-PHI polymer was formulated as a nanoparticle excipient for the first time by inverse emulsion polymerization. The nanoparticles were optimized with consideration of diameter, surface charge, size variability, and yield as a delivery vehicle for a custom vascular therapeutic peptide. A layer-by-layer (LBL) surface modification technique using poly-L-lysine was integrated within the nanoparticle design to optimize therapeutic loading efficiency. Solvent pH played a pivotal role in emulsion micelle formation, LBL polymer secondary structure, and the polymer functional group interactions critical for high therapeutic loading. The resulting nanoparticle platform met target size (200 ± 20 nm), polydispersity (<0.07), and storage stability standards, was nontoxic, and did not affect therapeutic peptide bioactivity in vitro. Surface-modified D-PHI nanoparticles can be reproducibly manufactured at low cost, generating a highly customizable excipient platform suitable for delivery of biomolecular therapeutics. These nanoparticles have potential applications in vascular drug delivery via localized infusion, drug eluting stents, and drug-coated angioplasty balloons. Statement of significanceNanoscale excipients have become critical in the delivery of many therapeutics to enhance drug stability and targeted biodistribution through careful design of nanoparticle composition, surface chemistry, and size. This manuscript describes the development of a nanoparticle excipient derived from an immunomodulatory degradable polar hydrophobic ionic polyurethane, in combination with a layer-by-layer surface modification approach utilizing poly-L-lysine, to transport a mimetic peptide targeting smooth muscle cell migration in vascular disease. The nanoparticle platform draws on the effect of pH to maximize drug loading and tailor particle properties. The low cost and easily reproducible system presents a highly customizable platform that can be adapted for therapeutic delivery across a wide range of clinical indications.

Effects of functional groups in polymers on rate of acid–rock reaction in reservoir stimulation

The focus of research on acid stimulation is to reduce the rate of the acid–rock reaction, which involves the infiltration of acid into deep formations. Gelled acids with high viscosity can decelerate the diffusion of hydrogen ions to decrease the rate of the acid–rock reaction. However, there have been few reports on the interactions between functional groups in polymers and rocks. In this study, three polymers (AA7, AA24, and AAS) with different functional groups were synthesized, and their effects on the acid–rock reaction were investigated. The results showed that the order of the abilities of the three polymers to delay the acid–rock reaction was as follows: AA24 > AA7 > AAS. The retardation rate for AA24, AA7, and AAS was 79.31%, 66.67%, and 40.23%, respectively. Adsorption experiments illustrated that AA7 and AA24 were adsorbed on the surface of calcite via hydrogen bonds formed by ethoxy groups, whereas AAS relied on the hydrophobic effect of the benzene ring. The anionic polymer AAS was subjected to a strong electrostatic effect in an acid solution, which caused the molecular chains to curl and impaired the retarding performance. This was proved by the fact that the viscosity dramatically decreased from 66.00 mPa s in an aqueous solution to 7.50 mPa s in an acid solution and the effective diameter decreased from 322.2 nm in an aqueous solution to 102.2 nm in an acid solution. In the cases of the nonionic polymers AA7 and AA24, there was little change in viscosity or effective diameter, whether in an acid solution or an aqueous solution. Scanning electron microscopy confirmed that the film formed by the adsorption of AA24 on the surface of calcite was denser than that formed by AA7 because more ethoxy groups were present in AA24, but the film exhibited some narrow cracks in the case of AAS. Atomic force microscopy demonstrated that the surface roughness of calcite etched by a retarding acid solution of AA24 was only 78 nm, whereas it was as high as 130 nm in the case of AAS, which was consistent with the retarding performance with regard to the acid–rock reaction. This research could contribute to improvements in carbonate acidizing for reservoir stimulation.

Octahedral molybdenum cluster complex with glycolate ligands and study of its activity in polyurethane polymerization process

Octahedral metal clusters [{M6X8}L6]2– (where M = Mo2+ or W2+, X = Cl–, Br– or I–, and L is an apical ligand typically with a charge of 1–) have shown promise in a great variety of applications, ranging from solar energy and catalysis to cancer diagnostics and therapy. However, these clusters are not stable in water – the most widely used medium in many practical fields. An effective way to utilize and stabilize these compounds is to incorporate them into organic matrices. Along with direct impregnation, clusters can be used as monomers in polymerization process due to the ease of an addition of polymerizable functional groups in cationic part or in apical ligand environment. In this work, new cluster with six terminal glycolate ligands, (Bu4N)2[{Mo6I8}(OOCCH2OH)6], has been obtained and studied using FTIR, TGA, EDX, etc. Cluster luminescence has been studied in the temperature range of 77–300 K. As have been demonstrated experimentally and theoretically, by the DFT calculations, the coordination of glycolic acid to the cluster drastically reduces the activity of the –OH group in the polymerization of polyurethane.

Simultaneous Formation of Polyhydroxyurethanes and Multicomponent Semi-IPN Hydrogels.

This study introduces an efficient strategy for synthesizing polyhydroxyurethane-based multicomponent hydrogels with enhanced rheological properties. In a single-step process, 3D materials composed of Polymer 1 (PHU) and Polymer 2 (PVA or gelatin) were produced. Polymer 1, a crosslinked polyhydroxyurethane (PHU), grew within a colloidal solution of Polymer 2, forming an interconnected network. The synthesis of Polymer 1 utilized a Non-Isocyanate Polyurethane (NIPU) methodology based on the aminolysis of bis(cyclic carbonate) (bisCC) monomers derived from 1-thioglycerol and 1,2-dithioglycerol (monomers A and E, respectively). This method, applied for the first time in Semi-Interpenetrating Network (SIPN) formation, demonstrated exceptional orthogonality since the functional groups in Polymer 2 do not interfere with Polymer 1 formation. Optimizing PHU formation involved a 20-trial methodology, identifying influential variables such as polymer concentration, temperature, solvent (an aprotic and a protic solvent), and the organo-catalyst used [a thiourea derivative (TU) and 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU)]. The highest molecular weights were achieved under near-bulk polymerization conditions using TU-protic and DBU-aprotic as catalyst-solvent combinations. Monomer E-based PHU exhibited higher Mw¯ than monomer A-based PHU (34.1 kDa and 16.4 kDa, respectively). Applying the enhanced methodology to prepare 10 multicomponent hydrogels using PVA or gelatin as the polymer scaffold revealed superior rheological properties in PVA-based hydrogels, exhibiting solid-like gel behavior. Incorporating monomer E enhanced mechanical properties and elasticity (with loss tangent values of 0.09 and 0.14). SEM images unveiled distinct microstructures, including a sponge-like pattern in certain PVA-based hydrogels when monomer A was chosen, indicating the formation of highly superporous interpenetrated materials. In summary, this innovative approach presents a versatile methodology for obtaining advanced hydrogel-based systems with potential applications in various biomedical fields.

Construction of Selective Ion Transport Polymer at Anode-Electrolyte Interface for Stable Aqueous Zinc-Ion Batteries.

Rampant dendrite formation and serious adverse parasitic reactions induced by migration of dissolved V/Mn cathode ions on Zn anode have hampered the high performance of aqueous zinc-ion batteries (AZIBs). Inspired by the coordination chemistry between functional groups of polymer and electrolyte ions, a freestanding layer consisting of dopamine-functionalized polypyrrole (DA-PPy) nanowires served as a selective ion transport layer at the anode-electrolyte interface to address these two issues, which could simultaneously avoid polarization caused by the introduction of an additional interface. On the one hand, the DA-PPy layer displays excellent zinc ion and charge transfer ability, as well as provides chemical homochanneling for zinc ions at the interface, which endow the DA-PPy layer with properties as a chemical guider and physical barrier for dendrite inhibition. On the other hand, the DA-PPy layer can trap excess transition metal ions fleeing from the cathodes, thus serving as a chemical barrier, preventing the formation of Vx+/Mnx+-passivation on the surface of the zinc anode. Consequently, the AZIBs based on V2O5 and MnO2 cathodes involving the DA-PPy functional layer show a great improvement in the capacity retention.

Component Fluctuation Modulated Gelation Effect Enable Temperature Adaptability in Zinc‐Ion Batteries

AbstractThe active H2O and slow ion kinetics behavior deteriorate the performance of aqueous zinc‐ion batteries at a wide temperature range, even in hydrogel electrolyte. Herein, a component fluctuation modulated gelation effect is applied to optimize Zn2+ solvation structure, realizing a balance between H2O activity limitation and Zn2+ kinetics retention. The as‐prepared hydrogel electrolyte via in situ copolymerization of [2‐(methacryloyloxy)ethyl] dimethyl‐(3‐sulfopropyl) and acrylamide in the electrolyte salt matrix facilitates stable overall performance at both normal and low temperatures. Theoretical calculations and experimental results attest that polymer functional groups exhibit a higher efficacy in substituting bound water in the Zn2+ solvated shell with the polymer content increasement, thereby alleviating water‐associated parasitic reactions. Furthermore, the hydrogel with abundant zwitterionic groups not only interacts with H2O to limit hydrolysis, but also constructs separated ionic migration channels to promote uniform and fast Zn2+ transport. As a result, the hydrogel electrolytes promote stable Zn2+ plating/stripping behaviors over 1050 h and 3000 h at 25 and −20 °C, respectively. The full batteries achieve a capacity retention of 98.8% over 2000 cycles at 25 °C and stably cycle for 600 times at −20 °C. This work yields novel insights into the development and design of hydrogel electrolytes.

Effect of vacuum–vibration–compaction molding on the properties and performances of polymer-modified cementitious material

The addition of polymers to cementitious materials can significantly enhance the water resistance of building structures operating under complex environments. The organic-inorganic cross-linked network established between the functional groups of polymers and inorganic materials significantly influences the properties of the matrix material. However, the gas-entrapping effect of polymers can have a detrimental effect on the pore structure of the paste, and the degree of organic-inorganic chemical reaction can impose a limitation on the use of polymers in cementitious materials. In this study, the vacuum-vibration-compaction (VVC) molding method was employed to improve the pore structure of the cement paste and to encourage organic-inorganic chemical reactions. The addition of the polymer did not significantly harm the pore structure compared to the paste obtained through the ordinary molding method. Consequently, in the VVC molding method, the addition of 5 wt% polymer significantly raised the content of Ca(COOH)2, a product of organic-inorganic chemical reaction, by 40.1 % and amplified the molecular chain length of the C–S–H structure by 39.0 % compared to the ordinary molding method. Furthermore, the polymer reduced water absorption by up to 66.0 %. Therefore, the VVC molding method can enhance waterproof of cementitious materials more efficiently with the use of polymers.

Fungal derived herbicidal metabolite loaded starch-chitosan-gum acacia-agar based bio composite: Preparation, characterization, herbicidal activity, release profile and biocompatibility

Biocomposites based on starch- gum acacia- agar, chitosan- starch- agar, starch- poly vinyl alcohol- agar were synthesized by simple, green route principles and the various characterization techniques like fourier infrared spectroscopy, SEM revealed the highly stable micro dimenstional that specially interacted with functional groups of polymers -herbicidal metabolites. Respective biocomposite was prepared by mixing equal volume of the selected polymer (1;1;1 ratio) with known concentration (100 mg of in distilled water followed by the addition of reconstituted herbicidal metabolites (100 mg or 0.1 g). Though all the biocomposites were capable of inducing herbicidal effect, notable impact was recorded in chitosan- starch- gum acacia treatment. In this case, the necrotic lesions were initiated at the early incubation period (6 h), progressively developing into dark brownish black lesions with 30.0 mm diameter. Release profile of the metabolites from the respective composite was also under in vitro and soil assay. Release profile study under in vitro and soil condition showed the sustained or controlled manner in distilled water and ethyl acetate treatment. No sign of toxic effect on the soil, parameters plant growth, rhizobacteria and peripheral blood cells clearly revealed the best biocompatibility of the presently proposed biocomposite.

Benzodithiophene‐Thienothiadiazole Copolymers as Dopant‐Free Hole‐Transporting Layers Enabling Efficient and Stable Perovskite Solar Cells

The exploration of dopant‐free hole‐transporting materials (HTMs) with excellent optoelectronic properties and defect passivation ability is of great significance for simultaneously improving the efficiency and stability of perovskite solar cells (PSCs). Herein, two donor–acceptor type conjugated polymers PTTDZ‐F and PTTDZ‐Cl with alternating benzodithiophene (BDT) and thienothiadiazole (TTD) units are successfully developed with desirable hole mobilities and conductivities. The formation of non‐covalent interaction (S···N) between thiophene bridge and TTD units significantly improves the co‐planarity of the molecular backbone and promotes the intramolecular charge transfer from BDT to TTD. The hydrophobicity and energy levels of the polymers are finely regulated via introducing different halogen atoms on the BDT moiety. Moreover, the functional groups in polymers efficiently passivate the surface charged traps in perovskite. As a result, champion power conversion efficiencies of 21.50% and 22.20% along with negligible hysteresis have been achieved for devices based on dopant‐free PTTDZ‐F and PTTDZ‐Cl, respectively. The unencapsulated devices also demonstrate excellent long‐term operational stability. Over 93% of their initial efficiencies can be retained after 320 h of maximum output power point tracking under 1 sun illumination. Herein, it paves a new avenue for developing highly stable and efficient HTMs for PSCs.

Preparation and characterization of wound healing hydrogel based on fish skin collagen and chitosan cross-linked by dialdehyde starch

Hydrogels due to high water absorption capacity, flexibility, biodegradability properties and also the ability to provide a moist environment, same as native extracellular, are widely used for wound healing applications. Developing multifunctional hydrogels using biomaterial is an emerging approach in this area. Collagen and chitosan are known as excellent biomaterials due to their properties, functionality, and sustainable sources. They also have good biocompatibility and biodegradability, suitable for wound healing hydrogels. In this study, the physicochemical characterization, morphology, and biocompatibility of collagen/chitosan/ dialdehyde starch hydrogel (Col/Ch/DAS) were evaluated. Type I collagen was extracted from silver carp skin by-product. DAS was synthesized by a one-step method of acid hydrolysis and oxidation. Hydrogels were made from collagen (4 % w/v) and chitosan mix (2 % w/v) and added DAS (2 % w/v) (0.5, 1.0 and 1.5 ml) as a cross-linker to enhance the physicochemical behaviors of the hydrogels. Swelling ratio, biodegradation, water vapor transmission rate (WVTR), surface morphology and the interactions between functional groups of polymers used in the hydrogel were evaluated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test of extracted collagen indicated the presence of two different α-chains in collagen and confirmed type I collagen. The results showed that DAS content significantly affected the swelling ratio and biodegradability of hydrogels (P < 0.05). Col/Ch/Das0.5 hydrogel showed the highest swelling and biodegradability compared to other hydrogels (P < 0.05). Col/Cs/DAS hydrogels showed suitable water vapor transmission for wound dressing. The Fourier transform infrared spectroscopy (FTIR) results showed that covalent bonds formed via acetalization and Schiff base reaction. The results suggested that the prepared hydrogel from silver carp fish skin collagen has excellent potential as a new wound dressing for medical and biomedical applications such as wound healing.

Characterization and Antioxidant Activity of Exopolysaccharides Produced by Lysobacter soyae sp. nov Isolated from the Root of Glycine max L.

Microbial exopolysaccharides (EPSs) have attracted attention from several fields due to their high industrial applicability. In the present study, rhizosphere strain CJ11T was isolated from the root of Glycine max L. in Goyang-si, Republic of Korea, and a novel exopolysaccharide was purified from the Lysobacter sp. CJ11T fermentation broth. The exopolysaccharide's average molecular weight was 0.93 × 105 Da. Its monosaccharide composition included 72.2% mannose, 17.2% glucose, 7.8% galactose, and 2.8% arabinose. Fourier-transform infrared spectroscopy identified the exopolysaccharide carbohydrate polymer functional groups, and the structural properties were investigated using nuclear magnetic resonance. In addition, a microstructure of lyophilized EPS was determined by scanning electron microscopy. Using thermogravimetric analysis, the degradation of the exopolysaccharide produced by strain CJ11T was determined to be 210 °C. The exopolysaccharide at a concentration of 4 mg/mL exhibited 2,2-diphenyl-1-picrylhydrazyl free-radical-scavenging activity of 73.47%. Phylogenetic analysis based on the 16S rRNA gene sequencing results revealed that strain CJ11T was a novel isolate for which the name Lysobacter soyae sp. nov is proposed.

Experimental investigation of wettability alteration of oil-wet carbonate surfaces using engineered polymer solutions: The effect of potential determining ions ([Mg2+/ SO42−], and [Ca2+/ SO42−] ratios)

Engineered water polymer flooding (EWPF) is a promising method to improve oil recovery in carbonate reservoirs holding more than half of the world's oil reserves. It involves combining engineered water (EW) and polymer flooding (PF) to modify rock wettability, reduce mobility ratio, promote polymer stability, and lower required polymer concentration. However, limited studies addressed the simultaneous effect of engineered water compositions (i.e. potential determining ions (PDIs)) on the viscosity of polymer and wettability alteration of various carbonate surfaces. Accordingly, this study aimed to investigate the effect of salinity, PDIs, and polymer functional groups (partially hydrolyzed polyacrylamide (HPAM), and acrylamide tertiary butyl sulfonic acid (ATBs)) on the wetting properties of calcite, chalk, and dolomite surfaces as well as the viscosity of solutions at static conditions. The experimental protocol included viscosity, contact angle (CA), pH, and static adsorption tests. Two combinations of PDIs were considered in the study: [Mg2+/SO42−], and [Ca2+/SO42−]. The results revealed that the polymer becomes more tolerant to the salinity as the sulfonation degree increases, given the same molecular weight. However, at a polymer concentration of 5000 ppm, the HPAM polymer showed higher viscosity than the ATBs-based polymers, as the formation brine (FB) was diluted to 100 folds (100DFB). The tendency of shifting the wettability of carbonate surfaces towards a more water-wet state using EW and EWP treatment solutions decreased in the following order: Chalk ≥ Calcite˃ Dolomite. The study also indicates that, the wettability alteration towards favorable condition is dependent on the initial wettability of the carbonate surface. The higher level of oil-wetness detected in aged dolomite, compared with calcite and chalk, resulted in less effectiveness of EWP for dolomites. However, the low polymer interaction with dolomite surfaces indicates a positive impact on reducing polymer consumption. Moreover, the HPAM polymer was more effective in altering the wettability of dolomite towards a water-wet state compared to the ATBs-based polymer. The overall results indicate that ATBs-based polymer is a potential candidate for optimizing the effectiveness of EWPF in carbonates.

Hydrogelation of polypeptide-poly(ethylene glycol)-polypeptide amphiphilic triblock copolymers using L-cysteine derivatives

The hydrogelation of amphiphilic triblock copolymers based on the poly(ethylene glycol) (PEG) and the sheet-like polypeptides was studied in this report. The triblock copolymers were synthesized by ring-opening polymerization (ROP) method using PEG-diamine with two different molecular weights as the hydrophilic initiators and polypeptides of two L-cysteine derivatives (S-methyl-L-cysteine and S-benzyl-L-cysteine) as the sheet-like, hydrophobic segments. The experimental data revealed that the polymer chain length, block ratio, and functional group on the side chain would dictate the amphiphilic balance and non-covalent interactions between the polymer chains, which consequently influence the hydrogelation of triblock copolymers and their hydrogel mechanical properties. The sheet-like poly(S-benzyl-L-cysteine) (PBLC) was found to be a good hydrogelator whilst the samples containing poly(S-methyl-L-cysteine) (PMLC) could not form hydrogels with polymer concentrations below 10 wt%. This study highlighted these amphiphilic triblock copolymers synthesizing by tethering sheet-like, hydrophobic polypeptide segments on both ends of a hydrophilic polymer could be an effective strategy for preparing hydrogels with tunable properties.

Modeling of polymer-enzyme conjugates formation: Thermodynamic perturbation theory and computer simulations

A simple model for the formation of the polymer-enzyme conjugates has been proposed and described using corresponding modification of the Wertheim's first-order thermodynamic perturbation theory (TPT) for the system of associating chain molecules. A set of computer simulation data for the polymer chains containing various number of functional groups was generated and used to testify the accuracy of the theoretical results. Predictions of the present theoretical approach are more accurate than that of the conventional TPT and are in a very good agreement with the computer simulation data. In particular, the theory is able to account for the difference in the position of the polymer functional groups along its backbone.

Effect of the Functional Groups of Polymers on Their Adsorption Behavior on Graphene Oxide Nanosheets

AbstractGraphene‐based polymer nanocomposites are emerging materials for both fundamental research and industrial applications. The influence of polymer functional groups on their adsorption behavior onto graphene oxide (GO) nanosheets is investigated, with poly(methyl methacrylate) (PMMA), poly(methyl methacrylate‐co‐methacrylic acid) (PMMA‐co‐MAA), and poly(methacrylic acid) (PMAA) having the same backbone but different functional side groups selected as the model polymers. Fourier transform infrared spectroscopy and X‐ray diffraction results confirm the interfacial interaction between the polymer and GO. Thermogravimetric analysis reveals notable enhancements in the amount of the adsorbed polymer up to 30.6 wt.% for PMMA‐co‐MAA/GO and 49.7 wt.% PMAA/GO compared with 18.7 wt.% for PMMA/GO. The water contact angle decreases from 71.3o for PMMA/GO to 69.1° for PMMA‐co‐MAA/GO and to 61.2° for PMAA/GO. The further washing process reduces the adsorption amount for the polymer/GO hybrid. Overall, the polar functional groups of the polymer directly influence the polymer adsorption behavior onto GO.

Applying Copolymerization Kinetics to Understand and Optimize Swelling Responses in Superabsorbent Hydrogels

While acrylic acid (AA)-based superabsorbent hydrogels (SAHs) have been widely used in multiple applications, the effects of counterion condensation and the polyelectrolyte effect at suppressing the effective degree of ionization in such systems limit their superabsorbency. Herein we describe the use, and investigate the mechanism, of sulfate comonomers containing different types of polymerizable functional groups for increasing the superabsorbency of acrylic acid-based SAHs. Specifically, acrylamido-2-methylpropanesulfonic acid (AMPS), 3-sulfopropyl acrylate (SPAK), and 3-sulfopropyl methacrylate (SPMK) sulfated monomers featuring similar distances between the polymer backbone and the sulfate group but different polymerizable groups were copolymerized with acrylic acid to fabricate SAHs. Measurements of the effective homopolymerization rate constants and copolymerization ratios associated with each copolymerization enabled the prediction of the relative chain distributions of monomers in each copolymer, as quantified by the blockiness parameter (i.e., the instantaneous or average number of consecutive monomers of each type polymerized). While all sulfated comonomers significantly enhanced swelling relative to an acrylic acid control, copolymers in which longer AA blocks are produced (AA-AMPS) resulted in lower swelling than copolymers in which shorter AA blocks are produced (AA-SPAK, AA-SPMK), a result attributed to the suppressed polyelectrolyte effect in copolymers with shorter AA blocks. The formation of limited length blocks of the sulfated monomer SPMK showed additional benefits for enhancing swelling, consistent with enhanced direct charge–charge repulsion between fixed charges in such copolymer systems. We anticipate this linkage between copolymerization kinetics and swelling properties offers the potential to enable improved rational design of superabsorbent hydrogels with higher sorbency.

Bacterial extracellular polymeric substances: Biosynthesis and interaction with environmental pollutants

Extracellular polymeric substances (EPS) are highly hydrated matrices produced by bacteria, containing various polymers such as polysaccharides, proteins, lipids, and DNA. Extracellular polymer concentrations, ions, and functional groups provide physical stability to the EPS. Constituents of EPS form the three-dimensional architecture and help acquire nutrition for the bacteria. Structural and functional diversity of the extracellular polymer depends on the specific glycosyltransferases, polymerase and transporter proteins. These enzymes are encoded by specific genes present in operons such as crd, alg, wca, and gum reported in Agrobacterium, Pseudomonas, Enterobacteriaceae, and Xanthomonas. The operons regulate the biosynthesis of extracellular polymers such as curdlan, alginate, colonic acid, and xanthan, respectively. Various functional groups in the EPS, such as carbonyl, hydroxyl, phosphoryl, and amide, provide the sorption site for interaction with environmental pollutants. Hydrophobic interactions and coordinate bonds mainly dominate the binding of EPS with environmental pollutants. EPS binds, emulsifies, and solubilizes the organic compounds, enhancing the degradation process. EPS binds with heavy metals through complexation, surface adsorption, precipitation, and ion exchange mechanisms. The biodegradability efficiency and nontoxicity properties of EPS make it an excellent biopolymer for decontaminating environmental pollutants. This review summarizes an overview of the biosynthetic mechanisms and interaction of the bacterial extracellular polymer with environmental pollutants. Interaction mechanisms of pollutants with EPS and EPS-mediated bioremediation will help develop removal applications. Moreover, understanding the genes responsible for EPS production, and implementation of new genetic methodology can be helpful for the enhanced biosynthesis of EPS to control pollution by sequestrating more environmental pollutants.

Revealing the hidden dynamics of confined water in acrylate polymers: Insights from hydrogen-bond lifetime analysis.

Polymers contain functional groups that participate in hydrogen bond (H-bond) with water molecules, establishing a robust H-bond network that influences bulk properties. This study utilized molecular dynamics (MD) simulations to examine the H-bonding dynamics of water molecules confined within three poly(meth)acrylates: poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(1-methoxymethyl acrylate) (PMC1A). Results showed that H-bonding dynamics significantly slowed as the water content decreased. Additionally, the diffusion of water molecules and its correlation with H-bond breakage were analyzed. Our findings suggest that when the H-bonds between water molecules and the methoxy oxygen of PMEA are disrupted, those water molecules persist in close proximity and do not diffuse on a picosecond time scale. In contrast, the water molecules H-bonded with the hydroxy oxygen of PHEMA and the methoxy oxygen of PMC1A diffuse concomitantly with the breakage of H-bonds. These results provide an in-depth understanding of the impact of polymer functional groups on H-bonding dynamics.

Fabrication of sub-5 nm uniform zirconium oxide films on corrugated copper substrates by a scalable polymer brush assisted deposition method

We demonstrate a polymer brush assisted approach for the fabrication of continuous zirconium oxide (ZrO2) films over large areas with high uniformity (pin-hole free) on copper (Cu) substrates. This approach involves the use of a thiol-terminated polymethyl methacrylate brush (PMMA-SH) as the template layer for the selective infiltration of zirconium oxynitrate (ZrN2O7). The preparation of a highly uniform covalently grafted polymer monolayer on the Cu substrate is the critical factor in fabricating a metal oxide film of uniform thickness across the surface. Infiltration is reliant on the chemical interactions between the polymer functional group and the metal precursor. A following reductive H2 plasma treatment process results in ZrO2 film formation whilst the surface Cu2O passive oxide layer was reduced to a Cu/Cu2O interface. Fundamental analysis of the infiltration process and the resulting ZrO2 film was determined by XPS, and GA-FTIR. Results derived from these techniques confirm the inclusion of the ZrN2O7 into the polymer films. Cross-sectional transmission electron microscopy and energy dispersive X-ray mapping analysis corroborate the formation of ZrO2 layer at Cu substrate. We believe that this quick and facile methodology to prepare ZrO2 films is potentially scalable to other high-κ dielectric materials of high interest in microelectronic applications.