Search Results (90)

Amphiphilic statistical copolymers are valuable synthetic macromolecules for the formation of small, well-defined nanoassemblies able to be utilized as nanocarriers for drug and/or gene delivery applications. In this work, the synthesis of amphiphilic linear statistical copolymers of the poly(benzyl methacrylate-co-dimethylaminoethyl methacrylate) [P(BzMA-co-DMAEMA)] type is described in three different comonomer compositions. Their synthesis was realized through a one-pot reversible addition-fragmentation chain transfer (RAFT) solution polymerization scheme. Further quaternization of the amine groups of DMAEMA with methyl iodide (CH₃I) resulted in cationic amphiphilic statistical copolymers. Macromolecular characterization was performed using size exclusion chromatography (SEC) and spectroscopic techniques (¹H-NMR and ATR-FTIR). The aggregation properties of the copolymers in aqueous media were studied via dynamic light scattering (DLS) and electrophoretic light scattering (ELS). Bimodal size distributions were determined in some cases. The BzMA to DMAEMA ratio determined aggregate size, with the copolymer of lower hydrophobic BzMA content producing smaller nanoparticles. Cryogenic transmission electron microscopy (cryo-TEM) showed the presence of spherical assemblies resulting from aggregation of primary micelles in the case of higher BzMA content. The copolymer aggregates experience dissociation at high salt concentration, and the pH-responsiveness of the amine precursors results in the formation of multifunctional potential nanocarriers. Full article

In this study, a polyvinyl alcohol/carboxymethyl chitosan (PVA/CCTS) hydrogel was synthesized via free radical polymerization and employed for the adsorption of Rhodamine B (RhB) from aqueous solution. The hydrogel was systematically characterized by FTIR, SEM, XPS, and BET analyses, confirming its interconnected porous network and functional group composition. Under optimized conditions (adsorbent dosage = 0.1 g, pH = 6, RhB concentration = 65 mg·L⁻¹, and T = 298.15 ± 2 K), the maximum adsorption capacity reached 15.88 mg·g⁻¹. Kinetic analysis showed that the pseudo-second-order model best described the adsorption behavior under optimal conditions, indicating that the uptake of RhB is governed by multiple interaction mechanisms rather than simple physisorption alone. The equilibrium data were best fitted by the Freundlich isotherm (R² = 0.976), indicating surface heterogeneity of the hydrogel. Thermodynamic evaluation revealed an endothermic (ΔH = 28.38 ± 4.40 kJ·mol⁻¹), with adsorption efficiency improving at elevated temperatures. The hydrogel retained appreciable adsorption capacity after three adsorption–desorption cycles (5.78 mg·g⁻¹ at the third cycle). Density functional theory (DFT) calculations identified -COOH and -NH₂ groups as the primary active sites, and molecular electrostatic potential analysis confirmed that electrostatic interactions between the negatively charged hydrogel surface and cationic RhB drive the initial adsorption. Molecular dynamics (MD) simulations over 100 ns further demonstrated that van der Waals forces constitute the dominant driving force, supplemented by electrostatic interactions and hydrogen bonding, with the hydrogel’s cross-linked network stabilizing adsorbed RhB molecules. The integrated experimental computational approach provides a comprehensive mechanistic understanding of RhB adsorption on PVA/CCTS hydrogel, offering guidance for the rational design of polysaccharide-based adsorbents for dye-contaminated wastewater treatment. Full article

The development of efficient and low-cost adsorbents for dye-contaminated wastewater remains an important challenge in environmental remediation. In this study, an interlayer-expanded polypyrrole/maghnite–Cu²⁺ nanocomposite (PPy/Mag–Cu²⁺) was successfully synthesized through purification of raw maghnite, sodium activation, Cu²⁺ ion exchange, and in situ oxidative polymerization of pyrrole. The obtained hybrid was characterized by X-ray fluorescence, X-ray diffraction, Fourier-transform infrared spectroscopy, UV–Vis spectroscopy, scanning electron microscopy, and cyclic voltammetry. The results confirmed the successful incorporation of Cu²⁺ and polypyrrole while preserving the layered aluminosilicate framework. XRD analysis revealed a progressive increase in basal spacing from 17.49 Å for raw maghnite to 25.95 Å for the final nanocomposite, indicating effective intercalation and formation of an expanded hybrid structure. The adsorption performance of PPy/Mag–Cu²⁺ was evaluated for methylene blue removal under batch conditions. Adsorption was strongly influenced by contact time, pH, and initial dye concentration, with equilibrium reached after approximately 80 min and optimum removal at pH 9. Equilibrium data were best fitted by the Langmuir model, with a maximum monolayer adsorption capacity of 43.66 mg g⁻¹, while kinetic data followed the pseudo-second-order model. These findings demonstrate that PPy/Mag–Cu²⁺ is a promising and cost-effective hybrid adsorbent for cationic dye removal from aqueous media. Full article

Perylene bisimide derivatives are typical n-type semiconductors as well as redox-active materials. However, it has been difficult to produce thin films by solution processes because of their low solubilities in organic solvents. Perylene bisimide derivatives bearing oligosiloxane moieties exhibit columnar phases over wide temperature ranges, including room temperature and high solubilities in organic solvents. The columnar phases are stabilized by nanosegregation between crystal-like one-dimensional π-stacks and liquid-like mantle consisting of oligosiloxane moieties. The electron mobility at room temperature exceeded 0.1 cm²V⁻¹s⁻¹ in the ordered columnar phases of perylene bisimide derivatives bearing four disiloxane chains. Uniaxially aligned thin films of the perylene bisimide derivatives bearing oligosiloxane moieties could be produced by a spin-coating method. The spin-coated films of the perylene bisimide derivatives bearing cyclotetrasiloxane rings could be insolubilized via in situ ring-opening polymerization by the exposure of the thin films to trifluoromethanesulfonic acid vapors. Uniaxially aligned thin films of perylene bisimide derivatives bearing an ethylene oxide chain as well as cyclotetrasiloxane rings could be doped in an aqueous solution of sodium dithionate, resulting in an anisotropic electrical conductivity. Polymerized thin films of perylene bisimide derivatives bearing a crown ether ring exhibited electrochromism in electrolyte solutions. These compounds formed 1:1 complexes with lithium triflate, exhibiting columnar phases at room temperature. The nanostructures of the complexes were stabilized by the electrostatic interaction between cationic crown-metal units and triflate anions. Full article

In this study, we designed a statistical polyampholyte bearing cationic quaternary ammonium salts and anionic phosphate groups as pendant functionalities. In addition, small amounts of o-nitrobenzyl groups, which generate anionic species upon photoirradiation, were introduced into the pendant chains to prepare a photo-responsive polyampholyte via reversible addition-fragmentation chain transfer radical polymerization. By increasing the feed ratio of the cationic monomer during copolymerization, a polyampholyte with a net positive charge was obtained. Upon photoirradiation of the aqueous solution of this cationic polyampholyte, the fraction of negatively charged groups in the polymer increased, resulting in a decrease in the zeta potential from positive values to around 0 mV. When the photo-responsive cationic polyampholyte was mixed with an anionic polyelectrolyte, poly(2-acrylamido-2-methylpropanesulfonate) (PAMPS), in water, micrometer-sized coacervate droplets were formed via electrostatic interactions. Photoirradiation of the aqueous coacervate system increased the fraction of negative charges in the polyampholyte, thereby weakening the electrostatic interactions with anionic PAMPS and resulting in the dissociation of the coacervates. Overall, this study presents a design guideline for polymeric materials in which interpolymer electrostatic interactions can be controlled by light to induce the disappearance of coacervates. Full article

Slickwater fracturing has become an adopted technology for enhancing hydrocarbon recovery from unconventional, low-permeability reservoirs such as shale and tight formations, owing to its ability to generate complex fracture networks at a low cost. Polyacrylamide and polyacrylamide-based gels serve as key additives in these fluids, primarily functioning as drag reducers and thickeners. However, downhole environments of high-temperature (>120 °C) and high-salinity (>1 × 10⁴ mg/L) reservoirs pose challenges, leading to thermal degradation and chain collapse of conventional polyacrylamide, which results in performance loss. To address these limitations, synthesis methods including aqueous solution polymerization, inverse emulsion polymerization, and aqueous dispersion polymerization have been developed. This review provides an overview of molecular design methods aimed at enhancing performance stability of polyacrylamide-based polymers under extreme conditions. Approaches for improving thermal stability involve synthesis of ultra-high-molecular-weight polyacrylamide, copolymerization with resistant monomers, and incorporation of nanoparticles. Methods for enhancing salt tolerance focus on grafting anionic, cationic, or zwitterionic side chains onto the polymer backbone. The drag reduction mechanisms and gelation methods of these polymers in slickwater fracturing fluids are discussed. Finally, this review outlines research directions for developing next-generation polyacrylamide polymers tailored for extreme reservoir conditions, offering insights for academic research and field applications. Full article

In this study, the solvent displacement method was used. This is a low-energy technique that generates a spontaneous “oil-in-water” nanoemulsion by diffusing ethanol from the oily phase to the aqueous phase. Subsequently, chitosan, a biocompatible and biodegradable cationic polymer, was incorporated, applying ionic gelation with sodium sulfate (Na₂SO₄) to achieve uniform coatings. Atomic force microscopy (AFM) characterization revealed nanocapsules with defined morphology and regular topography. Analysis with WSxM 4.0 Beta 10 software revealed a partially ordered hexagonal arrangement, which was evidence of controlled synthesis and the potential of chitosan as a polymeric system. Full article

A quaternized and phenyl-functionalized hyperbranched PEI-based sponge (S_HPEI-QP) was successfully prepared, and its adsorption performance was investigated to evaluate its potential for removing the anionic non-steroidal anti-inflammatory drug (ibuprofen (IBU)). We reported that the synthesis of polyethyleneimine-based sponges was achieved through cryo-polymerization using 1,4-butanediol diglycidyl ether (BDDE) as the crosslinking agent. Subsequent functionalization with resorcinol diglycidyl ether (RDGE) and trimethylamine introduced quaternary ammonium cations, imparting strong basicity and hydrophilicity, as well as phenyl groups, conferring hydrophobic characteristics, respectively. The aforementioned sponge material, S_HPE-QPI, primarily facilitates the efficient adsorption of IBU in aqueous solutions through the anion exchange properties of quaternary ammonium groups and the π-π interactions associated with oxygen-activated benzene rings. Various characterizations, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and specific surface area determination method (BET), confirmed the successful synthesis of the bifunctionalized S_HPEI-QP adsorbent. This adsorbent features a porous structure (specific surface area of 77.2 m² g⁻¹ and pore size distribution of 25–100 nm) and an isoelectric point (pH_pzc) of 9.38. The adsorption kinetics of the adsorbent for IBU were extremely rapid and conformed to a pseudo-second-order kinetic model, and the adsorption isotherm aligned with the Langmuir isotherm model. Noteworthily, S_HPEI-QP demonstrated an exceptionally high adsorption capacity for IBU, achieving a maximum uptake of 905.73 mg g⁻¹ at pH 7.0, which surpassed that of most of the previous reported adsorbents. Moreover, the sponge material can be chemically regenerated. After eight cycles of use, the adsorption efficiency decreased by only 4%. These findings suggest that the synthesized dendritic anion exchange adsorbent represents a promising candidate for the removal of IBU from contaminated water sources. Full article

Hydroxy-functional poly(propenyl ether)s are promising thermoresponsive materials; here we establish a controlled synthesis via living cationic polymerization of silyl-protected monomers. Among the silyl protecting groups examined, only tert-butyldiphenylsilyl (TBDPS) enabled living cationic polymerization. The living cationic polymerization of tert-butyldiphenylsiloxybutyl propenyl ether (TBDPSBPE) afforded a high-molecular-weight polymer (poly(TBDPSBPE)) with a narrow molecular weight distribution (M_n = 12,900; M_w/M_n = 1.22). Additionally, chain propagation continued in monomer addition experiments, and the molecular weight increased further with a narrow molecular weight distribution, confirming the success of living cationic polymerization. Poly(TBDPSBPE) was successfully desilylated to afford poly(HBPE) with a narrow molecular weight distribution. Poly(HBPE) exhibited a glass transition temperature (T_g) of 44 °C, 82 °C higher than that of the corresponding polymer without β-methyl groups, poly(HBVE). The enhanced thermal properties of poly(HBPE) were attributed to the steric hindrance of the β-methyl group, which fixes the position of the hydroxy group and allows stronger hydrogen bonding. To investigate the aqueous thermoresponse, a hydroxylated analog with a shorter side-chain spacer (poly(HPPE)) was synthesized, and poly(HPPE) exhibited lower critical solution temperature (LCST)-type phase separation in water with a cloud-point temperature (T_cp) of 6 °C, showing reversible transitions with thermal hysteresis. Full article

This work introduces 2-(azulen-1-yldiazenyl)-5-(thiophen-2-yl)-1,3,4-thiadiazole (L) as a functional monomer capable of forming stable, redox-active films with high affinity for lead in aqueous solutions. L was synthesized and characterized using physical chemical methods and electrochemistry. Polymer films of L were prepared through oxidative electro polymerization on glassy carbon electrodes in L solutions in 0.1 M TBAP in acetonitrile. They were characterized through electrochemistry. The surface of chemically modified electrodes (CMEs) prepared through controlled potential electrolysis (CPE) at variable concentrations, potentials, and electric charges was characterized through scanning electron spectroscopy, atomic force microscopy, and Raman spectroscopy, which confirmed the films’ formation. Electrochemical sensing of the films deposited on these CMEs was tested with respect to heavy metal (HM) ion analysis in aqueous solutions to obtain sensors for HMs. The obtained CMEs presented the best characteristics for the recognition of Pb among the investigated HMs (Cd, Pb, Cu, and Hg). Calibration curves were obtained for the analysis of Pb(II) in aqueous solutions, which allowed for the estimation of a good detection limit of this cation (<10⁻⁸ M) for non-optimized CMEs. The resulting CMEs show promise for deployment in portable environmental monitoring systems, with implications for public health protection and environmental safety. Full article

An increase in the production of cationic dyes is expected over the next decade, which will have an impact on health and the environment. This work reports an adsorbent hydrogel composed of poly(acrylic acid) [poly(AA)] and Fe₃O₄ particles, prepared by radical polymerization and in situ co-precipitation of Fe³⁺ and Fe²⁺. This Fe₃O₄/poly(AA) composite hydrogel was used to evaluate its potential for removing the cationic dyes methylene blue (MB) and crystal violet (CV) from aqueous solutions. Instrumental characterization of the hydrogel was performed by FTIR, XRD, TGA, VSM, and physicochemical analysis (swelling and response to changes in pH). The results show that the incorporation of Fe₃O₄ particles improves the adsorption capacity of MB and CV dyes to a maximum adsorption of 571 and 321 mg/g, respectively, under the best conditions (pH 6.8, dose 1 g/L, time 24 h). The adsorption data best fit the pseudo-first order (PFO) kinetic model and the Freundlich isothermal model, indicating mass transfer via internal and/or external diffusion and active sites with different adsorption potentials. Moreover, the thermodynamic analysis confirmed that the adsorption process was spontaneous and exothermic, with physisorption as the dominant mechanism. In addition, the Fe₃O₄/poly(AA) hydrogel is capable of removing 95% of the dyes after ten consecutive adsorption–desorption cycles, demonstrating the potential of hydrogels loaded with Fe₃O₄ particles for the treatment of wastewater contaminated with dyes. Full article

The rational design of functional and sustainable polymers is central to addressing global environmental challenges. In this context, unmodified lignin derived from Sarkanda grass (Tripidium bengalense), an abundant agro-industrial lignocellulosic byproduct, was systematically investigated as a natural polymeric adsorbent for the remediation of aqueous media contaminated with heavy metals. The study evaluates lignin’s behavior toward nine metal(loid) ions: arsenic, cadmium, chromium, cobalt, copper, iron, nickel, lead, and zinc. Adsorption performance was systematically investigated under static batch conditions, optimizing key parameters, with equilibrium and kinetic data modeled using established isotherms and rate equations. Surface characterization and seed germination bioassays provided supporting evidence. Unmodified Sarkanda grass lignin demonstrated effective adsorption, exhibiting a clear preference for Cu(II) followed by other divalent cations, with lower capacities for As(III) and Cr(VI). Adsorption kinetics consistently followed a pseudo-second-order model, indicating chemisorption as the dominant mechanism. Thermodynamic studies revealed spontaneous and endothermic processes. Bioassays confirmed significant reduction in aqueous toxicity and strong metal sequestration. This work positions unmodified Sarkanda grass lignin as a bio-based, low-cost polymer platform for emerging water treatment technologies, contributing to circular bioeconomy goals and highlighting the potential of natural polymers in sustainable materials design. Full article

Reversible addition–fragmentation chain-transfer (RAFT) polymerization was used to synthesize novel thermoresponsive cationic molecular brushes with high yields—namely of copolymers of methoxyoligo(ethylene glycol) methacrylate, alkoxyoligo(ethylene glycol) methacrylate, and N-methacryloylaminopropyl-N,N-dimethyl-N-propylammonium bromide. Controlled polymerization yielded polymers with a molecular weight dispersity of ≤1.3 and conversions exceeding 80%. The influence of the cationic molecular brushes’ composition on their solubility in water and organic solvents, interfacial tension at the water–oil interface, and aggregation behavior in aqueous solutions was investigated. For the first time, we report the design of thermoresponsive cationic molecular brushes combining an antibacterial potential and tunable hydrophilic–hydrophobic properties, enabling highly precise control over their LCST behavior (17–68 °C) through composition tuning. The solubilization capacity of the hydrophobic compounds of brush micelles in water increased with the hydrophobic comonomer content. These polymers exhibited interfacial activity, significantly reducing the water–oil interfacial tension, with critical micelle concentrations (CMCs) of 3–10 mg/L. It was shown that the amphiphilic properties of the copolymers in aqueous solutions can be easily tuned in a desired direction by varying the content of the comonomer units. The obtained data indicate the potential of the polymers as micellar nanocarriers for controlled drug delivery. Full article

Here, we report a reprocessible, reusable, self-healing, and form-switching polymeric adsorbent for remediating fluorinated pollutants in water. The copolymer hydrogel is designed to contain fluorophilic segments and cationic segments to induce strong binding with perfluorinated pollutants. The sorption performance reveals rapid and quantitative removal of these pollutants, driven by the synergistic effect of fluorophilic and electrostatic interaction. Importantly, a disulfide-containing dynamic crosslinker plays a crucial role in imparting multifunctionality. This enables self-healing by the restoration of crosslinks at the cut surfaces by disulfide exchange reactions and allows for the repeated use of the adsorbent via multiple adsorption–desorption cycles. Furthermore, the adsorbent is reprocessible by cleaving the crosslinks to afford linear copolymers, which can be repolymerized into a hydrogel network on demand. Also, form-switching capability is showcased through the aqueous self-assembly of linear copolymers into a fluorinated micelle, serving as another form of adsorbent for pollutant removal. Full article

Aggregation-induced emission dyes (AIEs) have gained significant interest due to their unique optical properties. Upon aggregation, AIEs can exhibit remarkable fluorescence enhancement. These systems are ideal candidates for applications in bioimaging, such as image-guided drug delivery or surgery. Encapsulation of AIEs in polymeric nanocarriers can result in biocompatible and efficient nanosystems. Herein, we report the fabrication of novel nanoaggregates formulated by amino terpolymer and tetraphenylethylene (TPE) AIE in aqueous media. Poly(di(ethylene glycol) methyl ether methacrylate-co-2-(dimethylamino)ethylmethacrylate-co-oligoethylene glycol methyl ether methacrylate), P(DEGMA-co-DMAEMA-co-OEGMA) hydrophilic terpolymer was utilized for the complexation of the sodium tetraphenylethylene 4,4′,4″,4‴-tetrasulfonate AIE dye. Fluorescence spectroscopy, physicochemical studies, and self-assembly in aqueous and fetal bovine serum media were carried out. The finely dispersed nanoparticles exhibited enhanced fluorescence compared to the pure dye. To investigate the role of tertiary amino groups in the aggregation phenomenon, the polymer was quaternized, and quaternized polymer nanocarriers were fabricated. The increase in fluorescence intensity indicated stronger interaction between the cationic polymer analog and the dye. A stronger interaction between the nanoparticles and fetal bovine serum was observed in the case of the quaternized polymer. Thus, P(DEGMA-co-DMAEMA-co-OEGMA) formulations are better candidates for bioimaging applications than the quaternized ones, presenting both aggregation-induced emission and less interaction with fetal bovine serum. Full article