Dispersion Polymerization Research Articles

Reversal of drug resistance in breast cancer cells by photodynamic action mediated by curcumin/Ko143/PLGA nanoparticles

Objective: The objective of this study is to prepare Cur/Ko143/PLGA that encapsulate the photosensitizer curcumin (Cur) and the multidrug transporter-specific inhibitor Ko143 to investigate its application in reversing drug resistance in breast cancer and evaluate its properties and therapeutic efficacy. Results: After successful preparation of nanoparticles, the encapsulation rate of Cur/Ko143/PLGA was 73.8% ± 1.8%, and the drug loading rate was 2.8% ± 0.1%. The Cur/Ko143/PLGA were spherical and regular in morphology under transmission electron microscopy. The nanoparticles were morphologically intact, were uniform in size, and did not show significant aggregation under scanning electron microscopy. The average particle size of Cur/Ko143/PLGA was 232.32 ± 10.60 nm, the polymer dispersion index was 0.01, and the zeta potential was −17.25 ± 0.65 mV, as determined by laser particle sizing. In vitro ultrasound observation showed that Cur/Ko143/PLGA were enhanced in both the B-mode and contrast modes. Intracellular Cur fluorescence detection, biocompatibility testing, cell scratch experiment, flow detection of apoptosis, live–dead staining, and actin polymerization test all prove that new nanomaterials have better photodynamic efficacy. Conclusion: Drug-carrying Cur/Ko143/PLGA nanoparticles can increase the concentration of the intracellular photosensitizer Cur and increase the photodynamic efficacy by inhibiting an efflux pump, which is expected to become a new therapeutic strategy.

Nanoparticle-Enhanced Water-Based-Emulsion Fracturing Fluid for Improved Imbibition Recovery in Unconventional Reservoirs: Performance and Mechanism

Summary The conventional friction reducer, typically a water-in-oil (W/O) emulsion, used in slickwater, encounters challenges related to poor environmental friendliness, limited stability, and low activity, hindering its widespread applicability. In this study, we synthesized a water-based emulsion through water dispersion polymerization, incorporating nanoparticles (NPs) into the process to enhance the stability and activity of the polymer emulsion. The result is an environmentally friendly, oil-phase-free, instantly dissolution, and highly efficient friction reducer, intended to optimize the utilization efficiency of slickwater. The NP-enhanced water-based emulsion demonstrated a consistent and spherical dispersion, featuring an average particle size of ~10 μm, maintaining stability for more than 6 months. With rapid dissolution in water, achieved within a mere 38 seconds, it facilitated continuous on-the-fly mixing. Slickwater composed of this emulsion exhibited outstanding application performance, yielding a remarkable 76% reduction in pipeline friction. The presence of NPs and specific monomers facilitated the formation of a spatial network structure that maintains high temperature/shear resistance even after prolonged shear. Moreover, the system exhibited an exceptional capacity for imbibition oil production. Indoor spontaneous imbibition experiments showed a final recovery rate of 32.41% in tight oil cores (~10% higher than conventional systems), and imbibition depth reached 40.2 mm (1.2-fold increase compared with traditional systems). Field experiments were conducted in a tight oil reservoir to validate practical applications; the results further validated the effectiveness of the novel system. The treated wells showcased rapid oil production, reaching an average daily production rate of 55.8 t/d and water content as low as ~31%, satisfying the predicted production target.

Waterborne polyurethane polymer dispersions using castor oil and curcumin as bioresources: Synthesis, characterization, and antibacterial textile applications

AbstractThe main goal of this study is to make new waterborne polyurethane polymers (WPUCs) using bioresources like curcumin as a chain extender and castor oil as a polyol. We explored different mole ratios of curcumin during the synthesis of WPUC polymers. The WPUC dispersions were well‐defined and had nanoparticle sizes that ranged from 80.1 to 48.2 nm. Their zeta potentials were between −61.7 and − 52.2 mV, which showed that they were more stable. The absence of a phenolic hydroxyl band in the synthesized WPUC's IR spectrum indicated the insertion of curcumin into the PU chain. The coating of WPUCs on polyester/cotton (PE/C) blend fabric showed an improvement in colorfastness properties and reduced air permeability. The enhanced bending modulus (enhanced stiffness), improved abrasion resistance, and higher tensile strength were also observed. Furthermore, the WPUC‐coated fabric samples showed a bacterial inhibition percentage of 83.12%–99.9999% (p < 0.001) compared with blank fabric against bacterias' because of the inherent nature of curcumin. Inserting a higher amount of curcumin in the polymer chain of WPUC improved the antibacterial effects. Overall, our findings provide valuable insights for the possible antibacterial textile applications of synthesized WPUCs.

Removing Conjugated Polymers from Aligned Carbon Nanotube Arrays.

Aligned carbon nanotube (A-CNT) with high semiconducting purity and high-density have been considered as one of the most promising active channels for field-effect transistors (FETs), but conjugated polymer dispersant residues on the surface of A-CNT have become the main obstacle for its further development in electronics applications. In this work, a series of removable conjugated polymers (CPs) are designed and synthesized to achieve favorable purification and alignment for CNT arrays with a high density of ≈360 CNTs/µm. Furthermore, a removal process of CPs on the CNT array film is developed. Raman spectra show that the CNTs in array film are almost not damaged after the removal process, and the G/D ratio is as high as 35. The field-effect transistors (FETs) are fabricated with a saturation current density up to 600µAµm-1 and a current on-off ratio of ≈105, even with a relatively long channel length of ≈3µm.

Dynamic Chalcogen Squares for Material and Topological Control over Macromolecules

AbstractHerein we introduce chalcogen squares via selenadiazole motifs as a new class of dynamic supramolecular bonding interactions for the modification and control of soft matter materials. We showcase selenadiazole motifs in supramolecular networks of varying primary chain length prepared through polymerization using tandem step‐growth/Passerini multicomponent reactions (MCRs). Compared to controls lacking the selenadiazole motif, these networks display increased glass transition temperatures and moduli due to the chalcogen bonding linkages formed between chains. These elastomeric networks were shown to autonomously heal at room temperature, retaining up to 83 % of the ultimate tensile strength. Lastly, we use post‐polymerization modification via the Biginelli MCR to add selenadiazole motifs to narrowly dispersed polymers for controlled topology in solution. Chalcogen squares via selenadiazoles introduce an exciting exchange mechanism to the realm of dynamic materials.

Dynamic Chalcogen Squares for Material and Topological Control over Macromolecules.

Herein we introduce chalcogen squares via selenadiazole motifs as a new class of dynamic supramolecular bonding interactions for the modification and control of soft matter materials. We showcase selenadiazole motifs in supramolecular networks of varying primary chain length prepared through polymerization using tandem step-growth/Passerini multicomponent reactions (MCRs). Compared to controls lacking the selenadiazole motif, these networks display increased glass transition temperatures and moduli due to the chalcogen bonding linkages formed between chains. These elastomeric networks were shown to autonomously heal at room temperature, retaining up to 83 % of the ultimate tensile strength. Lastly, we use post-polymerization modification via the Biginelli MCR to add selenadiazole motifs to narrowly dispersed polymers for controlled topology in solution. Chalcogen squares via selenadiazoles introduce an exciting exchange mechanism to the realm of dynamic materials.

Extrusion-based additive manufacturing of aluminium-filled ethylene vinyl acetate for electrically conductive 3D part printing

Addition of carbon-based fillers to enhance electrical conductivity is quite popular but addition of metal fillers is still a challenge due to oxidation and unavailability of metal nano-powders. In this paper, fabrication of flexible electrically conductive parts is proposed using aluminium metal powder as filler material. Aluminium metal powder is mixed with ethylene vinyl acetate (EVA) by chemical mixing process. Cyclohexane is used as a mixing medium in which EVA is dissolved and aluminium powder is added by weight. An in-house developed material extrusion tool mounted on CNC milling machine is used for printing of flexible electrically conductive samples. Pellet-based extrusion process is used for printing flexible parts as conventional filament-based 3D is not suitable due to buckling. Composite with filler loading in 5%, 10%, 20% and 30% were made and samples were printed. Investigations were made on printability of composite and its electrical conductivity. The aluminium fillers presence and dispersion in polymer were ensured. The samples were printed in temperature range of 130–140 °C through 0.4 mm diameter nozzle. It was found that the resistivity drops by around 60% on varying the filler concentration from 20% to 30%; 81.6 kΩ is the lowest resistance observed with 30% filler concentration. A simulation study on thermal behaviour of material extrusion tool has been done and is validated practically. The application of flexible electrically conductive parts lies in fabrication of various electronic devices like antenna, display boards, solar panels, and wearable health monitoring devices.

Phenanthroline Derived N-Doped Carbon Dots as Robust Metal-Free Photocatalysts for PET-RAFT Polymerization and Polymerization-Induced Self-Assembly.

Metal-free organic photocatalysts for photo-mediated reversible deactivation radical polymerization (photo-RDRP) are witnessed to make increasing advancement in the precise synthesis of polymers. However, challenges still exist in the development of high-efficiency and environmentally sustainable carbon dots (CDs)-based organocatalysts. Herein, N-doped CDs derived from phenanthroline derivative (Aphen) are prepared as metal-free photocatalysts for photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. The introduction of phenanthroline structure enhances the excited state lifetime of CDs and expands the conjugated length of their internal structure to enable the light-absorption to reach green light region, thereby enhancing photocatalytic activity. The as-designed CDs exhibit unprecedented photocatalytic capacity in photopolymerization even in large-volume reaction (100mL) with high monomer conversion and narrow polymer dispersity (Mw/Mn < 1.20) under green light. The photocatalytic system is compatible with PET-RAFT polymerization of numerous monomers and the production of high molecular weight polyacrylate (Mn >250000) with exquisite spatiotemporal control. Above results confirm the potential of CDs as photocatalyst, which has not been achieved with other CDs catalysts used in photo-RDRP. In addition, the construction of fluorescent polymer nanoparticles using CDs as both photocatalyst and phosphor through photoinitiated polymerization-induced self-assembly (Photo-PISA) technology is successfully demonstrated for the first time.

Effect of support type on the characteristics of polybutene polymers from C4 monomers employing supported ionic liquid/AlCl3 initiating systems

In order to assess the effect of support type on the characteristics of polybutene polymers, cyclohexyl imidazolium chloride ionic liquid was grafted onto the surface of various supports including boehmite, halloysite, palygorskite, and kaolinite. The furnished supported ionic liquids were employed alongside AlCl3/ethanol as initiating systems to polymerize C4 monomers, resulting in polybutene polymers. Overall, XRD, FTIR, TGA, SEM, EDS, and Elemental Mapping Analyses convinced the successful homogenous grafting of ionic liquid onto the surface of subjected supports. To obtain precious and essential information about molecular weight, dispersity, and microstructure of polymers, GPC, 1H NMR, and 13C NMR analyses were conducted. Among the four initiating systems, kaolinite supported ionic liquid demonstrated the most satisfying results, Yield = 88.2 %, Mn= 18104 g mol−1, Ð = 1.83, exo= 6.1 % and isobutylene content of 92.5 %. Hence, this supported ionic liquid was fully characterized via SEM, EDX, Elemental Mapping, XRD, FT IR and TGA analyses. To get deeper insight about the type and quantity of molecular interactions in the kaolinite supported ionic liquid, molecular modeling calculation was also considered. Beside efficiently balancing polymerization condition, implementing the AlCl3/ionic liquid initiating system promotes a more environmentally friendly polymerization approach by halving the amount of hazardous AlCl3 compared to the blank system including neat AlCl3 as the single co-initiator.

Initial Study on Rheological Behaviour of Hydroxyapatites / Polylactic Acid Composite for 3D Printing Filament

The present fused deposition modeling (FDM) printing process has concentrated on combining metal or ceramic filled with polymer because it could provide a strong composite in layered manufacturing technology in comparison to a single polymer material. However, the ability of the composite material to flow into the extruder becomes an obstacle because of the changes in the polymer concentration and dispersion of filler particles in producing the printed part. Hence, the rheological behavior of Hydroxyapatites (HAp) / Polylactic Acid (PLA) composite with different contents of HAp was studied to assess its ability to flow through the extruder during the 3D printing process. Measurements such as pycnometer density, thermal analysis (DSC) and FT-IR were performed on the composite feedstock containing a variation of 10% to 30% HAp powder. The feedstocks behavior then were characterized by rheological tests at three different temperatures (140 oC, 150 oC, and 160 oC). The composition of PLA/20HAp has produced optimum rheological behavior with effective flow behavior index (n) and activation energy (E) of 0.396 and 89.03 kJ/mol, respectively which is suitable for extruding out the HAp/PLA composite to become a 3D printing filament material.

Characterization of Ceria Nanoparticles as Abrasives Applied with Defoaming Polymers for CMP (Chemical Mechanical Polishing) Applications.

Chemical mechanical polishing/planarization (CMP) is an essential manufacturing process in semiconductor technologies. This method combines chemical and mechanical forces to smooth the surfaces of wafers. The effectiveness of CMP relies on a carefully chosen slurry, demanding a sophisticated manufacturing technology. This technology must seamlessly integrate both chemical composition and mechanical elements, highlighting the intricate synergy required for successful semiconductor fabrication. Particularly in milling processes, if agglomerated particles due to slurry particle corrosion are present during polishing, uneven polishing, numerous fine scratches occur, leading to an increase in roughness and a deterioration in the quality of the finished surface. In this study, to overcome the issue of particle agglomeration and uneven polishing in commonly used ceria nanoparticle slurries during CMP processes, we investigated the ceria nanoparticle behavior based on styrene-maleic acid (SMA) dispersant polymer applied with three types of defoaming polymers. The investigations are expected to open up the possibility of utilizing ceria nanoparticles with applied defoaming polymer as an abrasive for advanced CMP applications. All samples were characterized by DLS (dynamic light scattering), SEM-EDX (scanning electron microscopy-energy dispersive X-ray spectroscopy), pH, conductivity, viscosity, a 10-day stability test at 60 °C, the AF4 test, and the polishing rate efficiency test. Our research demonstrates a significant improvement achieved through the use of SMA dispersant polymer, resulting in a polishing selection ratio exceeding 80 for oxide and nitride films. The G-336 defoaming polymer utilized here is expected to serve as a viable alternative in CMP processes by providing stable uniformity.

Preparation and Application of Nitrobenzene-Containing Copolymer Nanoparticles Obtained by RAFT Dispersion Polymerization

Preparation and Application of Nitrobenzene-Containing Copolymer Nanoparticles Obtained by RAFT Dispersion Polymerization

Dispersion Polymerization of N‐Vinyl‐2‐Pyrrolidone in Supercritical Carbon Dioxide in the Presence of Thiol‐Terminated Poly(vinyl acetate‐co‐vinyl propionate)

AbstractLiquid carbon dioxide (LCO2) or supercritical carbon dioxide (ScCO2) can be used as an important solvent medium for preparing polymer particles through dispersion polymerization. However, based on the weak solvent characteristics of CO2, the development of stabilizers used in dispersion polymerization has always been an important challenge. These stabilizers are progressing toward the low‐cost, pollution‐free, and simple synthesis routes, et al. In this research, pentaerythritol tetra (3‐mercaptopropionate) (PTMP) is used to control the homopolymerization or copolymerization of vinyl acetate (VAc)/vinyl propionate (VPr), the homopolymers or copolymers with thiol group are synthesized by the one‐pot method. These homopolymers or copolymers are used as the stabilizers to stabilize the dispersion polymerization of N‐vinyl‐2‐pyrrolidone (NVP) in ScCO2. The results show that the structural unit proportion of the stabilizers, the concentration of stabilizers or 2, 2´‐azobis(isobutyronitrile) (AIBN), and the time interval for dispersion polymerization have significant impacts on the conversion percentage of NVP and the molecular weight of polymers. The maximum conversion percentage of NVP can get to 95%, and the molecular weight of poly(N‐vinyl‐2‐pyrrolidone)(PNVP) can reach 22.3 kPa. SEM analysis indicates that the PNVP obtained has regular spherical characteristics.

Synthesis of Self‐assembled Star/Linear Block Copolymer Blends via Aqueous RAFT Dispersion Polymerization

Comprehensive SummaryReversible addition‐fragmentation chain transfer (RAFT)‐mediated polymerization‐induced self‐assembly (PISA) of star block copolymer and linear block copolymer using a binary mixture of a star‐like macro‐RAFT agent and a linear macro‐RAFT agent is reported. With this formulation, star block copolymer and diblock copolymer were formed simultaneously to generate colloidally stable star/linear block copolymer assemblies. Size exclusion chromatography (SEC) analysis confirmed the presence of two types of polymers in the final samples. The molar ratio of the star‐like macro‐RAFT agent and the linear macro‐RAFT agent has a significant impact on the morphology of polymer assemblies. It was found that increasing the amount of star‐like macro‐RAFT agent facilitated the formation of higher‐order morphologies. Additionally, effects of other reaction parameters including the length/number of the arm of the star‐like macro‐RAFT agent, degree of polymer (DP), monomer concentration on the morphology of star/linear block copolymer assemblies were also investigated. We expect that this work will offer new possibilities for the scalable preparation of polymer assemblies with unique structures and functions.

Halloysite nanotubes-enhanced epoxy acrylate latex emulsion as a novel anticorrosive protective coating for metal surface in 3.5% NaCl solution.

Corrosion is a major problem that can lead to the degradation of metal structures. In this study, we developed a novel corrosion-protective coating for metal substrates based on a modified epoxy acrylate formulation reinforced with halloysite nanotubes (HNTs). Epoxy acrylate oligomers were first synthesized through the acrylation of epoxy using acrylic acid, followed by copolymerization with butyl methacrylate/vinyl acetate monomers to produce grafted epoxy acrylates (GEA). HNTs were then incorporated into the polymeric dispersion at weight loadings of 1%, 1.5%, and 2%. The corrosion resistance and waterproofing properties of the coatings were evaluated. The results showed that steel samples coated with HNTs-modified GEA showed no signs of rusting even after 16days of immersion in a corrosive solution, whereas those coated with GEA alone showed rusting after only 9days. These results demonstrate the effectiveness of HNTs-modified GEA coatings in protecting steel surfaces against corrosion. The coatings are also water-resistant and can be easily applied. This work provides a new approach to developing corrosion-protective coatings for metal substrates.

A novel double-layer liquid crystal electro-optic switch and its infrared shielding properties investigation

ABSTRACT In this study, a novel light switch was developed by integrating polymer dispersion liquid crystals (PDLC) and polymer-stabilised cholesteric liquid crystals (PSCLC), leveraging the infrared shielding properties of these two liquid crystal films. The optimal formulation for each layer of the liquid crystal structure was investigated. Subsequently, the effects of light intensity, high temperature, and humidity on the performance of the light switch were examined. This new light switch can be selectively driven layer by layer at room temperature, achieving three states: the off state, PDLC layer-driven state, and full-driven (on state). This functionality serves the purpose of electrogenerated temperature control. Samples under optimal conditions exhibited a 31% enhancement in infrared shielding compared to a single-layer PDLC film. Moreover, the IR shielding rate could be adjusted according to the voltage applied, realising an intelligent temperature-control effect. The results of this study suggest that such bilayer liquid crystal structures hold significant potential for application in electro-optical devices and smart curtain systems.

Voltage‐Driven Molecular Orientation with Optical Synergy in Rare Earth Doped Polymer Dispersed Liquid Crystals

AbstractAchieving reversible large‐span photoluminescence regulation still faces difficulties due to limitations in the design or preparation conditions of related materials. Herein, a universal strategy that combines voltage‐driven molecular orientation with optical synergy between rare earth (RE) doped materials and polymer dispersed liquid crystals (PDLC) is proposed to achieve large‐span reversible opto‐electrically synergistic induced multi‐response photoluminescence regulation. The obtained Eu(tta)3phen/PDLC composites can exhibit different emission colors reversible transform from purple to purplish‐pink depending on the excitation wavelength and the applied electric voltage. The interaction between PDLC and Eu(tta)3phen is analyzed and the field distribution of internal microstructures is simulated using the finite‐difference time‐domain method, providing a theoretical basis for the voltage‐dependent photon interactions. The potential applications of Eu(tta)3phen/PDLC composites for anticounterfeiting is suggested by demonstrating a proof‐of‐concept anticounterfeiting system based on the composites. The strategy of opto‐electrically synergistic induced multi‐response photoluminescence regulation, with general applicability, can be easily extended to other RE doped materials and PDLC systems, opening up new possibilities for photoluminescence regulation research.

Monodisperse sulfonated melamine formaldehyde resin microspheres: Synthesis by dispersion polymerization and light-diffusing performance characterization

The development and characterization of sulfonated melamine formaldehyde resin microspheres (SMF microspheres) as light diffusers in epoxy resin was presented in this paper. The SMF microspheres were prepared through dispersion polymerization with uniform particle size, smooth surface, and a high refractive index. The particle size of the microspheres was controllable within the range from 0.8 to 3.7 µm according to the pH during acidic condensation and the amount of melamine. Compared to traditional MF microspheres, SMF microspheres possessed unique sulfonic acid groups, higher primary amine content, and stronger polarity, which prevent agglomeration when mixed with epoxy resin. The SMF microspheres thus prepared were used as light-diffusing fillers with epoxy resin as matrix. Experimental results and single-particle Mie scattering simulations confirmed that SMF microspheres with a higher refractive index and smaller particle size exhibited higher light-shading efficiency and the haze of EP, demonstrating their outstanding light-diffusing performance. In summary, the significant potential application of SMF microspheres in the field of light diffusers was demonstrated.

Effect of electromagnetic field‐assisted freezing on improving the stability of lemon juice after thawing

AbstractThis study aims to reduce the production of flocculent material and stratification of lemon juice during freezing and thawing, using electric or magnetic fields to assist with the freezing of lemon juice. This study investigated the effect of 10–30 kV/cm electric field (EF) and 2–10 mT magnetic field (MF) on the quality of frozen lemon juice. Electromagnetic field treatment can shorten the freezing time and reduce its particle size, resulting in a lower polymer dispersion index and lower enzyme activity, thus improving its cloud stability. When the EF strength was 20 kV/cm and the MF strength was 6 mT, it resulted in the highest cloud stability, which increased by 15.50 and 16.95%, respectively. In addition, we studied the effect of electromagnetic fields on the physico‐chemical properties and bioactive components of lemon juice. The results showed that it did not affect its bioactive compounds activity and antioxidant activity, and did not cause loss of lemon juice flavor. The electromagnetic field treatment improved the quality of the juice and can be used as a potential novel processing technology for fruit juices.Practical ApplicationsThis study provides a simple and novel method to improve the stability of frozen lemon juice after thawing. The use of physical fields such as electric and magnetic field treatments to assist in freezing lemon juice improves the stability of lemon juice after thawing and provides a new method to improve the quality of fruit juice products.

Textile material-based grid structure for EM attenuation

This paper presents several aspects concerning materials with potential applications for electromagnetic shields. For this objective, grid structures coated by ultrasound treatments in conductive polymeric dispersions were designed to obtain appropriate models for electromagnetic attenuation. To anticipate the potential use of these samples in EM shields, the samples were analysed to observe the values for electrical resistance.