Colloid and Polymer Science最新文献

This work presents the development of AuNW@pNIPAM, a hybrid platform combining electron beam lithography (EBL)-fabricated gold nanowire arrays (AuNWs) with thermoresponsive poly(N-isopropylacrylamide) (pNIPAM) brushes. A functionalization strategy using aryl diazonium salts, developed in our group, enables the precise confinement of the pNIPAM brushes exclusively on the AuNWs via surface initiated atom transfer radical polymerization (SI-ATRP), achieving an optimized 9 nm polymer thickness. Temperature-induced changes in the hydration state of pNIPAM were characterized using atomic force microscopy (AFM) in liquid phase verus the temperature, revealing a significant collapse of the polymer layer above the lower critical solution temperature (LCST). Concurrently, UV–vis spectroscopy demonstrated a 7-nm red shift in localized surface plasmon resonance (LSPR) due to the phase transition and a 15-nm shift upon bovine serum albumin (BSA) adsorption showcasing enhanced plasmonic sensitivity for real-time biomolecular monitoring. The reversible temperature-controlled adsorption/desorption of BSA on the AuNW@pNIPAM surface highlights the potential of this hybrid platform for applications in biosensing, drug delivery, and other bio-interfacing technologies.

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This study used chitosan with functional groups and PVA polymer with strong film-forming-mechanical properties to obtain a new adsorbent material, and the usability of membranes bearing the combined effect of these materials in dye adsorption was investigated through experimental studies. To synthesize poly(vinyl alcohol)/chitosan (PVA/Cht) membranes, 6% (g/mL) PVA solution was mixed with a chitosan solution of 4% (g/mL) in a volumetric ratio of one to one. The PVA/Cht polymer mixture was processed into membranes via solvent casting and subsequently maintained at 150 °C for an hour to promote physical cross-linking. Fourier transform infrared spectroscopy (FTIR) was used to study the structural composition of the synthesized membranes, which verified the presence of PVA and chitosan. The membrane morphology was assessed using scanning electron microscopy (SEM), while energy dispersive spectroscopy (EDS) outcomes demonstrated the presence of carbon, oxygen, and nitrogen in the membranes. Thermogravimetric (TGA) analysis was also carried out to evaluate the membranes’ thermal stability. Following this, the membranes were also tested for their ability to adsorb Remazol Black B (RBB) dye under a range of experimental conditions. Maximum adsorption occurred with membranes at low pH (at pH 2). It was observed that adsorption time reached equilibrium in 24 h. During adsorption experiments at various incubation temperatures, the dye removing efficiency of the membranes improved with rising temperatures. When adsorption was performed with membranes at different initial dye concentrations, it was observed that there was no change in the adsorption capacity of membranes after a certain dye concentration. When adsorption experiments were conducted with varying initial adsorbent quantities, at a dye concentration of 800 mg/L, pH 2, 24-h incubation, and 0.02 g of adsorbent, the membranes reached a peak dye removing of 625.51 mg/g. Membranes have very high paint removing capacity. The usability of the obtained material as a potential adsorbent was proven; further studies will be carried out to develop the materials planned to be produced and put them into practice.

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A schematic diagram of the synthesis of polymeric films composed of PVA/Cht with superior adsorption capacity for the removal of RBB dye. Created with Biorender.com.

In situ gelling materials that rapidly form gels upon contact with body fluids are highly attractive for clinical applications. Boronate ester-crosslinked materials can create flexible, pH-responsive hydrogels. In this study, we focused on glucamine as the cis-diol-containing moiety in phenylboronic acid (BA) derivatives. We developed a modified hyaluronan acidic system composed of BA derivative-modified hyaluronan and glucamine-modified hyaluronan. 3-Amino-4-fluorophenylboronic acid and D-glucamine were modified onto sodium hyaluronate through condensation reaction, and mixed modified hyaluronan systems were prepared. We investigated the effect of pH on the rheological properties of the modified hyaluronan system and examined the binding constants (K) between BA derivatives and glucamine. The mixed modified hyaluronan system (pH 3.9) which combined the higher degree of substitution gelled quickly upon injection into a buffer solution at pH 7.4. The system exhibits significant pH dependence, with gelling properties increasing markedly as the pH rises from 4.4 to 7.4. For glucamine, the K values increased as the pD rose from 5.8 to 8.3. We concluded that successful pH-responsive in situ gelation requires a high degree of polymer substitution and strong K values between the BA derivative and the cis-diol moiety. Glucamine was identified as an effective cis-diol-containing moiety for BA derivatives.

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The anti-freezing and water-resistant gels strain sensors have great potential applications in flexible wearable devices, underwater communication, and deep-sea exploration. However, the poor adhesion, high swelling, low stretchability, or decreased conductivity of most gels in water hinders the stable signal transmission of the strain sensors. In this work, multifunctional polyionic gels with anti-freezing, water resistance, high adhesion, and wireless strain sensing ability were prepared by the one-step ultraviolet (UV) initiated copolymerization of butyl acrylate (BA), acrylic acid (AA), and 1-allyl-3-octylimidazole tetrafluoroborate ([AOIM][BF₄]). The high-density ionic groups in the macromolecular chains of poly(1-allyl-3-octylimidazole tetrafluoroborate) (P[AOIM][BF₄]) endowed the gels with excellent conductivity, which made the gel strain sensors suitable for monitoring the human joint movements, speech recognition, and other strain sensing. Because polybutyl acrylate (PBA) and P[AOIM][BF₄] are hydrophobic polymers, water molecules are hardly dispersed into the gel matrix, and the gels could maintain good flexibility and conductivity underwater or at low temperature. The gel sensors were connected with the wireless signal transmission module, which monitored finger tapping underwater, speech recognition, and human joint movement at − 20 ℃. The anti-freezing and water-resistant properties depended on the P[AOIM][BF₄] content in the gels. The anti-freezing, water resistance, and high adhesion provide the polyionic gels with new application prospects in telemedicine health, underwater communications, etc. Using UV irradiation to copolymerize ionic liquid monomers with traditional monomers for preparing the polyionic gels is efficient, environmentally friendly, and free of solvents. The strategy to fabricate the multifunctional gels could be expanded to other functional soft matters.

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The multifunctional polyionic gels could be used for underwater communication, speech recognition, and wireless motion monitoring at − 20 ℃.

Oil-in-water nanoemulsions as “nanoreactors” demonstrate application potential in constructing conductive polymer-based nanofunctional materials. This study introduces response surface methodology (RSM) to optimize the preparation process of the blank nanoemulsion, which is further used to synthesize polypyrrole (PPy) electrode materials. The blank nanoemulsions were prepared via a phase inversion emulsification method using a cyclohexane/Span 80-Tween 80/water system. A three-factor, three-level Box-Behnken design (BBD) was employed to reveal the dominant effect on the average droplet size of the nanoemulsion. Under conditions of an oil-to-emulsifier mass ratio of 2:1, an oil-to-water mass ratio of 1:10, and an emulsification temperature of 60 °C, a blank nanoemulsion with an average particle size of 130.3 ± 10 nm and an emulsification index of 99% was prepared. Utilizing this blank nanoemulsion as a confined reaction medium, nano-PPy electrode materials were synthesized via nanoemulsion polymerization. It was found that when the pyrrole (Py) monomer addition is less than 20 wt% of the dispersed phase, the Py has little impact on the properties of the original nanoemulsion system. The prepared spherical nano-PPy exhibits a specific surface area of 79.2 m² g⁻¹ and a particle size of ~ 100.0 nm, with a relatively narrow particle size distribution. Electrochemical test results indicate that the nano-PPy exhibits a specific capacitance of 153.4 F g⁻¹ at a current density of 0.5 A g⁻¹. After 2000 charge–discharge cycles, the capacitance retention rate is 63.6%, higher than other traditional in situ polymerization methods. This study provides new insights into the synthesis of conductive polymer electrode materials.

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The behavior of Na-carboxymethyl ether of chitin/chitosan (weak polyampholyte)—poly-N-acetyl-D-glucose-2-amine derivative—was studied in dilute solutions using a set of hydrodynamic methods (sedimentation velocity, translational diffusion, viscous flow of dilute solutions) in a wide range of ionic strengths from approximately 10⁻⁶ to 4.5 M NaCl. The molar masses and scaling relationships (Kuhn–Mark–Houwink–Sakurada equations) were determined in 0.2 M NaCl, where polyelectrolyte effects are virtually suppressed. The Kuhn segment length (persistent length) of chitin/chitosan Na-carboxymethyl ether chains in 0.2 M NaCl was estimated using the Multi-HYDFIT suite (A. Ortega et. al., 2011 Methods 54, 115–123. https://doi.org/10.1016/j.ymeth.2010.12.004), which is a method for computer processing of an array of experimental data obtained in a series of independent experiments. As a result, the following estimates were obtained: Kuhn segment length A = 24 ± 4 nm, hydrodynamic chain diameter d = 1.7 ± 0.7 nm. For the first time, using a method proposed earlier (G. M. Pavlov et al., 2006 Rus. J. Appl. Chem., 79(9), 1407–1412. https://doi.org/10.1134/s1070427206090035), intrinsic viscosity of Na-carboxymethyl ether of chitin/chitosan in salt-free solutions, where most strong polyelectrolyte effects were demonstrated, was estimated. Viscometric data were interpreted using the persistent cylinder theory (Yamakawa-Fujii), which led to an estimate of the equilibrium rigidity A ≥ 500 nm. This estimate is discussed within the framework of modern theories of polyelectrolyte linear chains.

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Based on first principles, the electronic structure and optical properties of monolayer WSe₂ doped with alkaline earth metal (Be/Mg/Ca/Sr/Ba) are investigated. The results show that all doping systems exhibit excellent formation potential and structural stability. Compared with monolayer WSe₂, alkaline earth metal doping induces lattice distortion and generates impurity levels. Meanwhile, the relative effective mass of electrons and holes in all doping systems is more deviated from one. Therefore, the recombination of photogenerated electron–hole pairs is effectively inhibited after doping. In addition, doping monolayer WSe₂ with alkaline earth metals increases its static dielectric constant and enhances its polarizability. Notably, the Mg-WSe₂ system exhibits the highest static dielectric constant, indicating the strongest polarization capacity. The absorption spectra of the doped system show a redshift in the low-energy region, which expands the response range to sunlight after the introduction of impurities. From band alignment analysis, we can conclude that other doping systems, except the Ba-WSe₂ system, show superior visible light absorption and effectively inhibit photogenerated electron–hole pair recombination, indicating their potential as photocatalysts for water decomposition.

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Monolayer WSe₂ within the two-dimensional transition metal dichalcogenides (TMDCs) material family exhibits broad potential in optoelectronic devices and photocatalysis owing to their direct bandgap characteristics. In this work, upon doping alkaline earth metal into a monolayer WSe₂, denoted as X-WSe₂ (X = Be, Mg, Ca, Sr, Ba), intriguing alterations are observed in the electronic and optoelectronic properties. Furthermore, apart from the Ba-WSe₂ system, other doped systems exhibit suitable energy band edge positions, making them promising candidates for high-performance photocatalysts.

The phase transition temperature dependence of polymer dispersed liquid crystals (PDLCs) leads to a narrow operating temperature range, especially in low-temperature environments prone to transparency anomalies or a significant increase in the drive voltage and other issues, which seriously limits its promotion in outdoor displays, automotive dimming glass, and other wide-temperature range applications. The narrow working temperature range is one of the significant factors limiting the wide applications of PDLC. In this paper, we have prepared a surfactant (Span-80)-doped PDLC. The different concentration of Span-80 has a significant impact on the electro-optical properties of PDLC at different temperatures. Based on the experimental results, doping of Span-80 can reduce the driving voltage and shorten the recovery time of PDLC at low temperatures. This innovation not only enhances the operational stability of PDLC devices at low temperatures, but also provides a sustainable optoelectronic architecture with minimized power consumption and accelerated switching dynamics, which is particularly beneficial for smart windows operating in low-temperature environments. In addition, a ball lubrication model is proposed, and the results of the ideal model agree with the experimental results.

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Panax notoginseng saponins (PNS) is a natural medicine known for its ability to promote blood circulation, remove blood stasis, reduce swelling, and relieve pain. However, obtaining high-purity PNS from the crude extract of the medicinal plant Sanqi is a challenging and important task. In this study, a novel rosin-based diatomite polymer microsphere (RDPMs) was synthesized, and its physical and chemical properties were characterized using various analytical techniques. The adsorption capacity of RDPMs for PNS was 273.69 mg·g⁻¹, with an increase in PNS content from 44.38 to 79.59%. The process was spontaneous, endothermic, and multilayered, controlled by physical and chemical factors. Quantum chemical calculations revealed that there are van der Waals forces, H-bonding, and electrostatic interactions between RDPMs and PNS. Overall, RDPMs is an effective and reusable bioadsorbent with potential for isolating PNS from Sanqi extract.

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This study investigates the use of PAN/EPI-DMA-bentonite composite fibers, synthesized through electrospinning, for the efficient adsorption of anionic azo dye, amido black (AB), in wastewater treatment. The composite fibers were developed by incorporating epichlorohydrin dimethylamine (EPI-DMA) modified bentonite into a polyacrylonitrile (PAN) matrix, enhancing the surface’s positive charge and increasing adsorption sites. Characterization using SEM–EDX, FTIR, and BET analyses confirmed successful bentonite integration, increased fiber diameter, and enhanced surface area, contributing to improved dye affinity. Adsorption experiments revealed that a 3 wt% EPI-DMA-bentonite dosage achieved optimal AB dye removal, with the composite demonstrating a maximum adsorption capacity of 1829 mg/g at 200 ppm dye concentration. Acidic conditions (pH 2–4) significantly improved adsorption efficiency, reaching up to 92% dye removal due to increased electrostatic attraction between the anionic dye and cationic sites on the composite fibers. Isotherm and kinetic studies indicated that the adsorption process adheres to the Langmuir isotherm model and pseudo-second-order kinetic model, suggesting monolayer adsorption and chemisorption mechanisms. Compared to conventional adsorbents, the PAN/EPI-DMA-bentonite composite exhibited superior adsorption capacity, highlighting its potential as an effective and scalable solution for industrial dye-laden wastewater treatment.

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