Colloid and Polymer Science最新文献

This study focuses on advancing epoxy-polyamide composites through the incorporation of chitosan, derived from crab shells, a sustainable polymeric bio filler known for its ability to enhance mechanical and thermal properties. Utilizing a solution casting technique, composites were fabricated by blending various concentrations of chitosan into the epoxy-polyamide matrix. Several analytical methods, including FT-IR, XRD, SEM, DSC, and mechanical testing, were used to evaluate the modifications and properties of the composites. FT-IR confirmed successful chitosan incorporation into the ER-PA composites, supported by SEM analysis showing improved structural integrity. XRD revealed prominent diffraction peaks, reflecting increased crystallinity and efficient chitosan integration. SEM indicated uniform chitosan dispersion on smooth surfaces, enhancing fracture toughness. Mechanical study of the 1% chitosan blend demonstrated superior results, with an elasticity of 6.79 GPa and fracture elongation of 2.2%, surpassing the 5% blend. DSC data showed improved thermal stability, with the uncured composite exhibiting endothermic behavior at 100 °C and exothermic behavior at 400 °C. TGA confirmed enhanced thermal properties up to 780 °C, particularly for the 1% Cs blend, which also displayed outstanding amorphous characteristics. Overall, the mechanical study confirmed Young’s best modulus, toughness, and tensile strength in the 1% blend. A noticeable shift toward higher temperatures during accelerated heating indicated enhanced material durability. These findings highlight the significant potential of chitosan to improve the mechanical strength and thermal stability of epoxy-polyamide composites, making them suitable for demanding engineering applications where endurance and performance are critical.

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The study focuses on the development and evaluation of a novel folate-gelatin-Poloxamer P407 (FA-Ge-P407) copolymer nanogel for the co-delivery of paclitaxel (PTX) and curcumin (CUR) in breast cancer therapy. The study aims to address the limitations of PTX, such as poor water solubility and drug resistance in cancer cells, by combining it with CUR, known for its anti-cancer properties and ability to inhibit drug resistance mechanisms. The FA-Ge-P407 nanogel was synthesized through a multi-step process involving the conjugation of folic acid (FA) onto a gelatin-Poloxamer P407 copolymer, which was characterized by FT-IR and HNMR spectroscopy. The nanogel particles were designed to encapsulate PTX and CUR, with their size, surface charge, and morphology thoroughly characterized using TEM and DLS techniques. In vitro release studies demonstrated that the presence of CUR enhanced and sustained PTX release, particularly under acidic conditions. The cytotoxicity assessment on MCF-7 breast cancer cells indicated that the FA-Ge-P407/PTX/CUR formulation exhibited superior anticancer activity compared to free PTX and FA-Ge-P407/PTX alone. The results suggest that FA-Ge-P407 nanogels offer a promising strategy for targeted breast cancer therapy, leveraging the combined effects of PTX and CUR to overcome drug resistance and achieve sustained therapeutic outcomes. Further studies are recommended to explore the in vivo efficacy and clinical potential of this advanced drug delivery system.

This work summarizes strategies to enhance the colloidal stability of styrene-acrylic latexes under industrial-relevant operating conditions, using anionic alkenyl ether phosphate (Maxemul™ 6106) and nonionic alkenyl ethoxylated polymerizable surfactants (Maxemul™ 5010) for waterborne paints. The influence of polymerizable surfactants mixed with conventional anionic surfactant and semi-batch seeded emulsion polymerization on the colloidal stability, particle size, zeta potential, electrolyte stability, water absorption of the polymer films, wet scrub resistance, and water absorption of the paint films were investigated. The contribution of semi-batch seeded operating conditions on the colloidal stability of poly(St/BA/AA/AM) latexes and on the waterborne paints was studied. The results showed a significant improvement in the latex stability against coagulation and end-use properties when compared to unseeded latex. The use of semi-batch seeded emulsion polymerization enhanced the application properties of the latex and paints based on the polymerizable surfactant mixtures. When polymerizable surfactant was used together with conventional anionic surfactant in semi-batch seeded conditions, stable latexes, particle sizes ranging from 105 to 130 nm, and better scrub resistance of the paint films were obtained. The use of polymerizable surfactants helps to reduce the total amount of surfactant in the latex recipe. Furthermore, the use of semi-batch seeded conditions helps in the control of particle size, coagulum content, electrolyte stability of the latexes, and increased wet scrub resistance of the paint films. The use of a seed latex prepared in situ provides additional insights for the production of poly(St/BA/AA/AM) latexes characterized by an increase in both colloidal stability and wet scrub resistance of the paint films.

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A multifunctional polymer (HAMP) for performance optimization of the spacers is presented based on 2-acrylamido-2-methyl propane sulfonic acid (AMPS), maleic anhydride (MA), acrylic acid (AA), and surfactant monomer. Specifically, HAMP was endowed with amphiphilic properties and thermo-associate behavior by introducing surfactant monomer and hydrophobic groups, respectively. Thus, HAMP has the potential for synergies with surfactant due to their amphiphilic properties and exhibits thermo-thickening behavior due to the thermo-associate behavior. These two properties are applied to the removal of oil-based drilling fluids and to increase the stability of spacers. Tests shows that: HAMP can synergize with ionic/non-ionic surfactant to increase the interface activity of surfactant/HAMP mixture; HAMP solution exhibits continuous thermo-thickening behavior at temperature above 70 °C when its concentration is higher than 0.3%, which can mitigate the consistency reduction of spacers at high temperature; the surfactant/HAMP mixture has higher removal efficiency and better temperature and salt resistance than the single surfactant solution; rheological property changes little in the range from 25to 90 ℃, and 0.3% HAMP can prevent the sedimentation of weighted spacer. Series of mechanism experiments indicate that more association forms a denser micronetwork at higher temperature, which leads to the thermo-thickening behavior of HAMP; the groups with different charges and hydrophobic groups in HAMP can make it better adsorbed on the surface and the components the oil-based filter cake, resulting in wetting modification of the surface and stabilizing oil-base components, which are conducive to the removal of the oil-based drilling fluid. It is hoped that the multifunctional polymer proposed in this paper can be applied in various fields.

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Solar-driven interface evaporation for steam and electricity co-generation is expected to simultaneously solve the shortage of freshwater and energy. Although many different solar-driven evaporators have been developed, the simultaneously achieving freshwater-electricity cogeneration at a steadily high efficiency remains a challenge. In this work, an anisotropic graphene aerogel (AGA) with vertically aligned microfluidic channels is synthesized by a directional-freezing method. By unidirectionally transporting the saline, the AGA not only shows stable steam generation but also generates continuous electricity due to the formation of an asymmetric electric double-layer. For seawater desalination, the evaporation rate reaches about 2.82 kg m⁻² h⁻¹ under one sun irradiation. And the evaporation performance has no obvious attenuation after long-term usage due to self-operating salt rejection. During the seawater evaporation, the AGA can generate output voltage of ca. 0.85 V and short-circuit current of 0.01 mA. The AGA has the advantages of strong light absorption, high photothermal conversion ability, low thermal conductivity, low-cost, excellent salt rejection ability, making it very attractive for practical applications. Therefore, this work will provide a new opportunity for simultaneous solar desalination and electricity generation under natural sunlight.

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Although the correlation between the regularity of micro-structures and the length of side chains has been widely reported, experiments still require precursors of polynorbornene derivatives due to the complex inter- and intra-chain interplay. This research utilizes hydrogen bonding between amide groups to design molecular models of polynorbornene derivatives (PNbs). The PNbs are abbreviated as Pm-8, where “m” indicates the amount of methylene groups as spacers in the side chain, and “8” refers to the oxyoctyl tail. The aim is to obtain a gradual variation of inter- and intra-chain interplay for further elucidation. Based on an analysis of spatial descriptors, mean square displacement (MSD), and radial distribution function (RDF) by using molecular mechanics (MM) and molecular dynamics (MD) methods, it is found that the asymmetry of side chains plays a more significant role in determining micro-structural regularity than the length. Highly asymmetric side chains are favorable for forming inter-chain hydrogen bonding, promoting interdigitation, and creating a larger scale of regularity in P8-8 and P10-8 molecules. In contrast, the relatively symmetric side chains tend to form intra-chain bonding, resulting in limited regularity within P2-8 and P4-8 molecules. Therefore, unlike regular structures that usually require symmetrical molecules, polynorbornene derivatives with asymmetric side chains have achieved highly ordered orthorhombic lattices in experiments. This study aims to offer an alternative approach to screening effective precursors of long-side chain polymers by means of semi-quantitative geometric parameters, providing a fresh perspective on the subject. 

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Chemical structure and molecular geometry of the P8-8 model of polynorbornene derivatives (color code: purple = the main chain, red = O, white = H, gray = C) The P8-8 model of polynorbornene derivatives has an asymmetric micro-structure that promotes interdigitation of side chains, creating a larger scale of regularity in bulk structure. The name of the model is derived from the number of methylene groups as spacers and the oxyoctyl tail in the side chain, both of which are represented by the number 8.

In this study, an aluminate coupling agent (ACA) was utilized to modify calcium carbonate (CaCO₃) particles, producing modified CaCO₃ (Al-CaCO₃) particles, which were subsequently employed as inorganic fillers to enhance the toughness of polylactide (PLA). PLA/Al-CaCO₃ composites were prepared through melt mixing, with the reaction between ACA and CaCO₃ confirmed by Fourier transform infrared (FTIR) spectroscopy. The mechanical, thermal, and biodegradation properties of these composites were thoroughly investigated. The addition of Al-CaCO₃ significantly enhanced the mechanical properties, with impact strength reaching approximately 9.7 kJ/m², a 143% increase compared to neat PLA. The elongation at break also improved dramatically, rising from 7.5 to 34%, representing a 350% increase over neat PLA. Al-CaCO₃ particles demonstrated good dispersibility and strong interfacial interaction within the PLA matrix. Differential scanning calorimetry (DSC) results showed that Al-CaCO₃ enhanced the crystallization behavior of PLA, promoting the formation of more perfect crystals. Additionally, biodegradation tests revealed that the PLA/Al-CaCO₃ composites exhibited excellent biodegradation properties. The combined toughening and biodegradation properties of PLA/Al-CaCO₃ broaden the potential applications of PLA.

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In this paper, the effect of surfactant type (cationic, anionic, nonionic, and zwitterionic) on the detachment of hexadecane droplets from the quartz surface was investigated. The results indicated that the oil detachment performance was controlled by the adsorption behavior of surfactant molecules at the interface between the solid and liquid phases, which could alter the solid–liquid interfacial tension (IFT). In the cationic solution, IFTs of solid-oil and solid-water decreased and increased, respectively, ascribed to the electrostatic attraction occurring between the positively charged hydrophilic group and the negatively charged quartz surface. Conversely, in the anionic solution, the anionic surfactant with a negative head group increased the oil-solid IFT because of its electrostatic repulsion with the quartz surface, increasing the oil contact angle and subsequently oil droplet detachment under the hydrodynamic effect. In addition, the results obtained from the adhesive force test showed that nonionic and zwitterionic surfactants had the capability of preventing the re-adhesion of solid and oil, whereas the anionic surfactant had the best performance among the four types of surfactant for oil detachment from quartz surface.

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Designing new nanozyme systems as a simple substitute of natural enzymes with higher catalytically active sites and stability has attracted growing research interests for widespread applications especially in environmental remediation. Laccases belong to a group of multicopper-containing enzymes that show significant potential in diverse biotechnological and bioremediation applications. In this paper, a facile strategy is reported for the preparation of an efficient laccase mimic inspired by structural features and electron transfer mechanism of natural laccase, via Cu²⁺ ions doping in ZIF8 framework (denoted as Cu-ZIF8). Cu-ZIF8 nanozyme showed laccase-like activity and significant catalytic performance in the oxidation of a wide range of phenolic pollutants such as 2,4-dichlorophenol, phenol, catechol, hydroquinone, and o-nitrophenol. Kinetic studies were carried out to estimate the kinetic parameters of the as-prepared Cu-ZIF8 nanozyme including apparent Michaelis–Menten constant (K_m) and maximum velocity (V_max). The K_m and V_max were calculated to be 0.28 mM and 0.017 mM min⁻¹, respectively. In addition, Cu-ZIF8 nanozyme was robust over a wide range of temperature (30–90 °C), at extreme pH and high salt concentration. In addition, Cu-ZIF8 nanozyme can catalyze the oxidation of dopamine to a brown product, where an absorption band at 290 nm was observed. Accordingly, a simple colorimetric assay has been established for detection of dopamine in the linear range of 0.01–0.44 mM with a detection limit of 1.1 × 10⁻³ mM (S/N = 3). The developed colorimetric method showed good selectivity and high sensitivity in measuring dopamine among potential interfering components.

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A series of 2,2-diallyl-1,1,3,3-tetraethylguanidiniumchloride copolymers with N-vinylpyrrolidone (AGC-VP), vinylacetate (AGC-VA), and methacrylic acid (AGC-MAA) were obtained by free radical polymerization reaction. The guanidinium copolymers were loaded with silver nanoparticles, and there were investigated cytotoxic properties of the synthesized nanocomposites along with the features of interaction with model membranes (small anionic liposomes). The nanocomposites have a selective cytotoxic activity against cancer cell lines. Nano(AGC-VP) provokes a noticeable increase in cellular apoptosis in a dose-dependent manner and has great prospects as apoptosis inducer of A549 cells triggering only apoptotic cell death. All nanocomposites complexed with liposomes; herewith, the features of interaction with the lipid membrane were dependent on the composition of the copolymer in the nanocomposite. Nano(AGC-VA) had no destructive effect towards the liposomes and, in the case of Nano(AGC-MAA), negligible defect formation was observed. At the same time, Nano(AGC-VP) induced lateral segregation of lipids and formation of defects in the bilayer that resulted in irreversible interaction with liposomes. Detailed studies of the physicochemical aspects of liposome-to-nanocomposites interactions make it possible to understand the mechanism of action of composite materials, thereby bringing us closer to the possibility of practical application of the latter.