Search Results (28)

Gel materials are widely used in underground mining for air leakage sealing and coal spontaneous combustion prevention. In this study, a novel self-healing carboxymethyl cellulose-modified amphiphilic polymer hydrogel with fire prevention and extinguishing capabilities is synthesized through ionic crosslinking between CMC-graft-poly(AM-co-NaA-co-BAM) and aluminum citrate (AlCit). The copolymer is constructed by grafting sodium carboxymethyl cellulose (CMC) onto an amphiphilic polymer backbone composed of acrylamide (AM), sodium acrylate (NaA), and N-benzylacrylamide (BAM), forming a dual-network structure via hydrophobic association and hydrogen bonding. The carboxymethyl cellulose-modified amphiphilic polymer demonstrates optimal viscosity-enhancing performance at a CMC content of 7.5 wt%. CMC-graft-poly(AM-co-NaA-co-BAM) demonstrated superior temperature, shear, and salt resistant performance compared with poly(AM-co-NaA-co-BAM), poly(AM-co-NaA), and CMC polymers, as well as enhanced viscoelasticity and self-healing capability. When crosslinked with AlCit, CMC-graft-poly(AM-co-NaA-co-BAM)-AlCit gel demonstrated superior viscoelastic properties and self-healing capability, as well as thermal stability, which gave the superior fire prevention and extinguishing performance for charcoal in fire extinction tests. CMC-graft-poly(AM-co-NaA-co-BAM) has abundant cross-linking sites, which lead to accelerated gelation and improved mechanical strength, while the hydrophobic microdomains acted as physical cross-linking points that interconnected polymer chains into a three-dimensional network. The hydrophobic interactions within the hydrogel are dynamically reversible. This intrinsic property allows physical cross-links to spontaneously reassociate when fracture surfaces make contact. Consequently, the material exhibits autonomous self-healing. Full article

In this study, we report the synthesis of amphiphilic hyperbranched poly[(2-dimethylaminoethyl methacrylate)-co-(benzyl methacrylate)] statistical copolymers with two different stoichiometric compositions using the reversible addition–fragmentation chain transfer polymerization (RAFT) technique. The selection of monomers was made to incorporate a pH and thermoresponsive polyelectrolyte (DMAEMA) component and a hydrophobic component (BzMA) to achieve amphiphilicity and study the effects of architecture and environmental factors on the behavior of the novel branched copolymers. Molecular characterization was performed through size exclusion chromatography (SEC) and spectroscopic characterization techniques (¹H-NMR and FT-IR). The self-assembly behavior of the hyperbranched copolymers in aqueous media, in response to variations in pH, temperature, and ionic strength, was studied using dynamic light scattering (DLS), electrophoretic light scattering (ELS), and fluorescence spectroscopy (FS). Finally, the efficacy of the two novel copolymers to encapsulate curcumin (CUR), a hydrophobic, polyphenolic drug with proven anti-inflammatory and fluorescence properties, was established. Its encapsulation was evaluated through DLS, UV–Vis, and fluorescence measurements, investigating the change of hydrodynamic radius of the produced mixed copolymer–CUR nanoparticles in each case and their fluorescence emission properties. Full article

Double hydrophilic, random, hyperbranched copolymers were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) utilizing ethylene glycol dimethacrylate (EGDMA) as the branching agent. The resulting copolymers were characterized in terms of their molecular weight and dispersity using size exclusion chromatography (SEC), and their chemical structure was confirmed using FT-IR and ¹H-NMR spectroscopy techniques. The choice of the two hydrophilic blocks and the design of the macromolecular structure allowed the formation of self-assembled nanoparticles, partially due to the pH-responsive character of the DMAEMA segments and their interaction with -COOH end groups remaining from the chain transfer agent. The copolymers showed pH-responsive properties, mainly due to the protonation–deprotonation equilibria of the DMAEMA segments. Subsequently, a nanoscopic polymer–lipid (lipomer) mixed system was formulated by complexing the synthesized copolymers with cosmetic amphiphilic emulsifiers, specifically glyceryl stearate (GS) and glyceryl stearate citrate (GSC). This study aims to show that developing lipid–polymer hybrid nanoparticles can effectively address the limitations of both liposomes and polymeric nanoparticles. The effects of varying the ionic strength and pH on stimuli-sensitive polymeric and mixed polymer–lipid nanostructures were thoroughly investigated. To achieve this, the structural properties of the hybrid nanoparticles were comprehensively characterized using physicochemical techniques providing insights into their size distribution and stability. Full article

This manuscript serves as the starting point for in-depth research of multicomponent, statistical, methacrylate-based copolymers that potentially mimic the behavior of proteins in aqueous solutions. These synthetic macromolecules are composed of specially chosen comonomers: methacrylic acid (MAA), oligoethylene glycol methyl ether methacrylate (OEGMA₄₇₅), 2-(dimethylamino)ethyl methacrylate (DMAEMA) and benzyl methacrylate (BzMA). Monomer choice was based on factors such as the chemical nature of pendant functional groups, the polyelectrolyte/polyampholyte and amphiphilic character and the overall hydrophobic–hydrophilic balance (HLB) of the obtained quaterpolymers. Their synthesis was achieved via a one-pot reversible addition fragmentation chain transfer (RAFT) polymerization in two distinct compositions and molecular architectures, linear and hyperbranched, respectively, in order to explore the effects of macromolecular topology. The resulting statistical quaterpolymers were characterized via ¹H-NMR and ATR-FTIR spectroscopies. Their behavior in aqueous solutions was studied by dynamic (DLS) and electrophoretic light scattering (ELS) and fluorescence spectroscopy (FS), producing vital information concerning their self-assembly and the structure of the formed aggregates. The physicochemical studies were extended by tuning parameters such as the solution pH and ionic strength. Finally, the quaterpolymer behavior in FBS/PBS solutions was investigated to test their colloid stability and biocompatibility in an in vivo-mimicking, biological fluid environment. Full article

The synthesis of amphiphilic diblock and statistical (random) copolymers of poly(dimethylamino ethyl methacrylate) and poly((2-(diisopropylamino) ethyl methacrylate) using the reversible addition–fragmentation chain transfer polymerization technique (RAFT polymerization) is reported. The precursor copolymers were chemically modified to create derivative copolymers of polyelectrolyte and polyampholyte nature with novel solution properties. Moreover, their molecular and physicochemical characteristics, as well as their self-assembly in aqueous media as a function of molecular architecture and composition, are investigated by using size exclusion chromatography, spectroscopic characterization techniques and light scattering techniques. Furthermore, the behavior and properties of the obtained micelles and aggregates were studied, depending on the pH, temperature and ionic strength of the aqueous solutions. The response of the systems to changes in these parameters shows interesting behavior and new properties that are useful for their utilization as nanocarriers of pharmaceutical compounds. Full article

This study investigates the effect of an inert salt (NaCl) on the equilibrium interfacial tension and dilatational modulus of Pluronic F-68 copolymer, a triblock copolymer consisting of two terminal blocks of poly(ethylene oxide) and a less hydrophilic central block of poly(propylene oxide). Interfacial tension measurements were carried out using a surface force balance and a drop shape tensiometer, while rheological measurements were carried out in two different frequency ranges. This involved the use of the oscillatory barrier/droplet method and electrocapillary wave measurements, complemented by an appropriate theoretical framework. This work aimed to elucidate the influence of NaCl on the interfacial behavior of Gibbs monolayers of Pluronic F-68. In addition, this study highlights some of the technical and theoretical limitations associated with obtaining reliable dilatational rheological data at high frequencies (<1 kHz) using electrocapillary wave measurements. The results provide valuable insights into the interplay between salt presence and interfacial properties of Pluronic F-68 and highlight the challenges of obtaining accurate dilatational rheological data under specific measurement conditions. Full article

Previously obtained amphiphilic graft copolymers based on [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TMAMA) ionic liquid were used as the matrices of three types of nanocarriers, i.e., conjugates with ionic piperacillin (PIP) and micelles with tazobactam (TAZ), which represented single systems, and dual systems bearing PIP anions and encapsulated TAZ for co-delivery. The exchange of Cl anions in TMAMA units with PIP ones resulted in a yield of 45.6–72.7 mol.%. The self-assembling properties were confirmed by the critical micelle concentration (CMC), which, after ion exchange, increased significantly (from 0.011–0.020 mg/mL to 0.041–0.073 mg/mL). The amphiphilic properties were beneficial for TAZ encapsulation to reach drug loading contents (DLCs) in the ranges of 37.2–69.5 mol.% and 50.4–80.4 mol.% and to form particles with sizes of 97–319 nm and 24–192 nm in the single and dual systems, respectively. In vitro studies indicated that the ionically conjugated drug (PIP) was released in quantities of 66–81% (7.8–15.0 μg/mL) from single-drug systems and 21–25% (2.6–3.9 μg/mL) from dual-drug systems. The release of encapsulated TAZ was more efficient, achieving 47–98% (7.5–9.0 μg/mL) release from the single systems and 47–69% (9.6–10.4 μg/mL) release from the dual ones. Basic cytotoxicity studies showed non-toxicity of the polymer matrices, while the introduction of the selected drugs induced cytotoxicity against normal human bronchial epithelial cells (BEAS-2B) with the increase in concentration. Full article

Aiming at the fundamental understanding of solvent effects in amphiphilic polymer systems, we considered poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO-PPO-PEO) block copolymers in water mixed with an ionic liquid—ethylammonium nitrate (EAN), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆), or 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF₄)—and we investigated the hexagonal lyotropic liquid crystal structures by means of small-angle X-ray scattering (SAXS). At 50% polymer, the hexagonal structure (cylinders of self-assembled block copolymer) was maintained across the solvent mixing ratio. The effects of the ionic liquids were reflected in the characteristic length scales of the hexagonal structure and were interpreted in terms of the location of the ionic liquid in the self-assembled block copolymer domains. The protic ionic liquid EAN was evenly distributed within the aqueous domains and showed no affinity for the interface, whereas BMIMPF₆ preferred to swell PEO and was located at the interface so as to reduce contact with water. BMIMBF₄ was also interfacially active, but to a lesser extent. Full article

Previously reported amphiphilic linear and graft copolymers, derived from the ionic liquid [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TMAMA_Cl‾), along with their conjugates obtained through modification either before or after polymerization with p-aminosalicylate anions (TMAMA_PAS‾), were employed as matrices in drug delivery systems (DDSs). Based on the counterion type in TMAMA units, they were categorized into single drug systems, manifesting as ionic polymers with chloride counterions and loaded isoniazid (ISO), and dual drug systems, featuring ISO loaded in self-assembled PAS conjugates. The amphiphilic nature of these copolymers was substantiated through the determination of the critical micelle concentration (CMC), revealing an increase in values post-ion exchange (from 0.011–0.063 mg/mL to 0.027–0.181 mg/mL). The self-assembling properties were favorable for ISO encapsulation, with drug loading content (DLC) ranging between 15 and 85% in both single and dual systems. In vitro studies indicated ISO release percentages between 16 and 61% and PAS release percentages between 20 and 98%. Basic cytotoxicity assessments using the 2,5-diphenyl-2H-tetrazolium bromide (MTT) test affirmed the non-toxicity of the studied systems toward human non-tumorigenic lung epithelial cell line (BEAS-2B) cell lines, particularly in the case of dual systems bearing both ISO and PAS simultaneously. These results confirmed the effectiveness of polymeric carriers in drug delivery, demonstrating their potential for co-delivery in combination therapy. Full article

Bioactive linear choline-based copolymers were developed as micellar carriers for drug delivery systems (DDSs). The polymethacrylates containing trimethylammonium groups with p-aminosalicylate anions (PAS-based copolymers: series 1) or chloride anions (Cl-based copolymers: series 2) differing in ionic content and chain length were selected for drug loading. The diverse structures of amphiphilic copolymers made it possible to adjust the encapsulation efficiency of a well-known antibiotic, i.e., p-aminosalicylate in the form of sodium salt (PASNa) or acid (PASA), providing single drug systems. Goniometry was applied to verify the self-assembly capacity of the copolymers using the critical micelle concentration (CMC = 0.03–0.18 mg/mL) and the hydrophilicity level quantifying the surface wettability of polymer film using the water contact angle (WCA = 30–53°). Both parameters were regulated by the copolymer composition, indicating that the increase in ionic content caused higher CMC and lower WCA, but the latter was also modified to a less hydrophilic surface by drug encapsulation. The drug content (DC) in the PAS-based polymers was increased twice by encapsulation of PASNa and PASA (47–96% and 86–104%), whereas in the chloride-based polymer systems, the drug was loaded in 43–96% and 73–100%, respectively. Efficient drug release was detected for PASNa (80–100% series 1; 50–100% series 2) and PASA as complete in both series. The strategy of loading extra drug by encapsulation, which enhances the drug content in the copolymers containing anions of the same pharmaceutics, provided promising characteristics, which highlight the potential of PAS-loaded micellar copolymers for drug delivery. Full article

Block copolymers synthesized via Atom Transfer Radical Polymerization from alkyl acrylate and t-butyl acrylate and the subsequent hydrolysis of the t-butyl acrylate to acrylic acid were systematically varied with respect to their hydrophobic part by the variation in the alkyl chain length and the degree of polymerisation in this block. Depending on the architecture of the hydrophobic part, they had a more or less pronounced tendency to form copolymer micelles in an aqueous solution. They were employed for the preparation of IPECs by mixing the copolymer aggregates with the polycations polydiallyldimethylammonium chloride (PDADMAC) or q-chit. The IPEC structure as a function of the composition was investigated by Static Light and Small Angle Neutron Scattering. For weakly-associated block copolymers (short alkyl chain), complexation with polycation led to the formation of globular complexes, while already existing micelles (long alkyl chain) grew further in mass. In general, aggregates became larger upon the addition of further polycation, but this growth was much more pronounced for PDADMAC compared to q-chit, thereby leading to the formation of clusters of aggregates. Accordingly, the structure of such IPECs with a hydrophobic block depended largely on the type of complexing polyelectrolyte, which allowed for controlling the structural organisation via the molecular architecture of the two oppositely charged polyelectrolytes. Full article

Polyethylene-b-polypeptide copolymers are biologically interesting, but studies of their synthesis and properties are very few. This paper reports synthesis and characterization of well-defined amphiphilic polyethylene-block-poly(L-lysine) (PE-b-PLL) block copolymers by combining nickel-catalyzed living ethylene polymerization with controlled ring-opening polymerization (ROP) of ε-benzyloxycarbonyl-L-lysine-N-carboxyanhydride (Z-Lys-NCA) and sequential post-functionalization. Amphiphilic PE-b-PLL block copolymers self-assembled into spherical micelles with a hydrophobic PE core in aqueous solution. The pH and ionic responsivities of PE-b-PLL polymeric micelles were investigated by means of fluorescence spectroscopy, dynamic light scattering, UV-circular dichroism, and transmission electron microscopy. The variation of pH values led to the conformational alteration of PLL from α-helix to coil, thereby changing the micelle dimensions. Full article

The peculiarities of viscosity data treatment for two series of polymer systems exhibiting associative properties: brush-like amphiphilic copolymers—charged alkylated N-methyl-N-vinylacetamide and N-methyl-N-vinylamine copolymer (MVAA-co-MVAC_nH_2n+1) and charged chains of sodium polystyrene-4-sulfonate (PSSNa) in large-scale molecular masses (MM) and in extreme-scale of the ionic strength of solutions were considered in this study. The interest in amphiphilic macromolecular systems is explained by the fact that they are considered as micellar-forming structures in aqueous solutions, and these structures are able to carry hydrophobic biologically active compounds. In the case of appearing the hydrophobic interactions, attention was paid to discussing convenient ways to extract the correct value of intrinsic viscosity $\left[\eta \right]$ from the combined analysis of Kraemer and Huggins plots, which were considered as twin plots. Systems and situations were demonstrated where intrachain hydrophobic interactions occurred. The obtained data were discussed in terms of $\ln {\eta }_{\mathrm{r}}$ vs. $c\left[\eta \right]$ plots as well as in terms of normalized scaling relationships where ${\eta }_{\mathrm{r}}$ was the relative viscosity of the polymer solution. The first plot allowed for the detection and calibration of hydrophobic interactions in polymer chains, while the second plot allowed for the monitoring of the change in the size of charged chains depending on the ionic strength of solutions. Full article

The rampant growth of zinc dendrites and severe uncontrollable reactions have largely limited the industrialization of aqueous Zn-ion batteries. Electrolyte additive engineering was found to be a facile yet effective strategy in addressing these issues; however, traditional organic small molecule additives raise additional safety and health risks and thus compromise the intrinsic advantage of aqueous batteries. In this study, we report a polyacrylonitrile-co-poly(2-acrylamido-2-methylpropanesulfonic acid) (PAN-co-PAMPS) copolymer with ionic and hydrophilicity PAMPS and non-ionic PAN, which acts as an electrolyte additive to regulate the Zn deposition in aqueous Zn-ion batteries. The hydrophilicity of PAMPS is designed to meet water solubility. Moreover, ionic PAMPS reacts with a Zn anode surface, chemically peels the surface, leaves a pre-polished anode surface, and removes heterogeneity and impurity of the metal surface. All these effects are beneficial for homogeneous zinc ion deposition and long-life battery. The PAN segments act as a water-shielding layer on a Zn anode to prevent its direct contact with H₂O. Consequently, the Zn|Zn symmetric cells with additive-containing electrolytes have a much longer life than those without additives (up to eight times) at a current density of 1 mA cm⁻² and a capacity of 1 mA h cm⁻². The assembled Zn|Cu cells and the Zn|V₂O₅ full batteries also display prominent electrochemical reversibility. The reactively acidic amphiphilic polymer provides not only an alternative strategy for the design of multi-functional electrolyte additives, but also constitutes an easy-to-operate way for advancing commercialization of aqueous zinc-storage devices. Full article

Scientific research based on the self-assembly behavior of block copolymers (BCs) comprising charged-neutral segments has emerged as a novel strategy mainly looking for the optimization of efficiency in the generation and storage of electrical energy. The sulfonation reaction re- presents one of the most commonly employed methodologies by scientific investigations to reach the desired amphiphilic character, leading to enough ion concentration to modify and control the entire self-assembly behavior of the BCs. Recently, several works have studied and exploited these changes, inducing improvement on the mechanical properties, ionic conduction capabilities, colloidal solubility, interface activity, and stabilization of dispersed particles, among others. This review aims to present a description of recent works focused on obtaining amphiphilic block copolymers, specifically those that were synthesized by a living/controlled polymerization method and that have introduced the amphiphilic character by the sulfonation of one of the segments. Additionally, relevant works that have evidenced morphological and/or structural changes regarding the pristine BC as a result of the chemical modification are discussed. Finally, several emerging practical applications are analyzed to highlight the main drawbacks and challenges that should be addressed to overcome the development and understanding of these complex systems. Full article