Core-shell Polymer Research Articles

Bioderived Thiol-Ene Emulsion Polymerization for Hybrid Latex Particles.

The thiol-ene emulsion polymerization of three dienes synthesized from bioderived compounds, and subsequent preparation of core-shell polymer latexes, is reported. Levoglucosan (LGA), levogucosenone (LGO) and isosorbide were first modified with 4-pentenoic acid to install polymerizable groups. These monomers were used along with a dithiol to prepare poly(thioether) particles via ab initio emulsion polymerization using potassium persulfate as initiator and sodium dodecyl sulfate as surfactant. The structure of the diene significantly influenced the size of the resulting polymer latex particles. Given their low glass transition temperature, the LGA-derived poly(thioether) particles were used as a seed for the seeded emulsion polymerization of either styrene or methyl methacrylate. Core-shell latex particles with a high Tg core and a low Tg bioderived shell were formed, as verified by electron microscopy and in agreement with theoretical predictions of the equilibrium particle morphology based on the interfacial tensions of each particle phase.

Poly(vinyl alcohol)-Incorporated Core-Shell Polymer Nanogels Functionalized by Block Copolymer Installation for Cisplatin Delivery.

The functionalization approach for nanomaterials is of great importance for their application in drug delivery systems. Herein, an approach based on block copolymer installation into polymer nanogels was newly developed. Poly(vinyl alcohol)-incorporated polymer nanogels were prepared by a two-step dispersion/precipitation polymerization. Poly(methacrylic acid)-block-poly(3-fluorophenylboronic acid methacrylamide) (PMAA-b-PFPBMA) prepared by two-step reversible addition-fragmentation chain transfer polymerization was installed into the polymer nanogels via boronate ester formation. Furthermore, cisplatin as a cancer therapeutic drug was successfully loaded on the block copolymer-installed polymer nanogels, and cell death was achieved by using the resulting cisplatin-loaded nanogels. We believe that the functionality of the nanogels can be changed by varying the installed block copolymer, leading to the functionalization approach of polymer nanogels based on block copolymer installation, which will be of great utility in many fields.

Biocide-encapsulated core–shell polymer microspheres: A novel approach for preparing long-lasting antimicrobial coatings

Antimicrobial coatings play a crucial role in combating pathogenic microorganisms. However, developing long-lasting antimicrobial coatings presents substantial challenges. In this study, we developed a robust method for fabricating durable antimicrobial coatings using crosslinked, biocide-encapsulated core–shell polymer microspheres. These microspheres were prepared by emulsion polymerization, facilitating simultaneous synthesis and biocide loading. Designed with a hydrophilic shell and a hydrophobic core, the microspheres predominantly stored the hydrophobic biocides within the core, thus reducing the biocide concentration at the shell. This design, which is governed by Fickian diffusion, substantially slowed the rate of biocide migration from the shell to the external environment, thereby enhancing the coating's antimicrobial longevity. The synthetic process for these biocide-encapsulated microspheres was optimized to encapsulate biocides with a Log P range of 1–3, achieving an encapsulation efficiency exceeding 85 % for all tested biocides. Specifically, microspheres containing N-butyl-1,2-benzisothiazolin-3-one (BBIT) were used to develop an antimicrobial coating. The coating can be applied to various substrates, including glass, metal, wood, ceramics, and plastics. It exhibits excellent hardness, adhesion, mechanical strength, and solvent resistance on these surfaces. Antimicrobial tests and release analyses demonstrated that the coating maintains high biological activity for at least 10 months, effectively inhibiting bacterial and fungal growth. The release behavior of the coating adhered to the Peppas–Sahlin model, with diffusion as the predominant mechanism. The model predicted an antimicrobial retention rate of over 66 % after 1 year, confirming its sustained antimicrobial effectiveness.

Optimizing synthesis and application of an enhanced oil recovery agent: stability assessment of the optimized nanostructured PNIPAM/PS core–shell polymer using a developed DLVO-based model

Optimizing synthesis and application of an enhanced oil recovery agent: stability assessment of the optimized nanostructured PNIPAM/PS core–shell polymer using a developed DLVO-based model

Encapsulation of Cadmium-Free InP-based Quantum Dots in Cross-Linked Core-Shell Microparticles via Coaxial Electrospraying.

Quantum dots (QDs) are inorganic semiconductornanocrystalscapable of emitting light. The current major challenge lies in theuseofheavy metals, which are known to be highly toxic to humans and pose significant environmental risks. Researchers have turned to indium (In) as a promising option for more environmentally benign QDs, specifically indium phosphide (InP). A significant obstacle remains in sustaining the long-term photostability of InP-based QDs when exposed to the environment. To tackle this, electrospraying is used in this work to protect indium phosphide/zinc selenide/zinc sulfide (InP/ZnSe/ZnS) QDs by embedding them within polymer core-shell microparticles of poly[(lauryl methacrylate)-co-(ethylene glycol dimethacrylate)]/poly(methyl methacrylate)(poly(LMA-co-EGDMA)/PMMA). During the flight of droplets, the liquid monomer core of LMA and EGDMA with QDs is encapsulated by the solid shell of PMMA formed due to solvent evaporation, resulting in a liquid-core/solid-shell particle structure. After that, the captured core of monomers is polymerized into a cross-linked polymer with the embedded QDs via a thermal initiation. They demonstrate how a successful core-shell particle formation is achieved to produce structures for initially liquid monomer systems via coaxial electrospraying that are used for cross-linked polymers, which are of major interest for the encapsulation of InP-based QDs for generally improved photostability over pristineQDs.

Size- and Shape-controlled Biodegradable Polymer Brushes Based on l-Amino Acid for Intracellular Drug Delivery and Deep-Tissue Penetration.

We report size- and shape-controlled polymer brushes based on l-amino acid bioresource and study the role of polymer topology on the enzymatic biodegradation and deep-tissue penetration under in vitro and in vivo. For this purpose, l-tyrosine-based propargyl-functionalized monomer is tailor-made and polymerized via solvent-free melt polycondensation strategy to yield hydrophobic and clickable biodegradable poly(ester-urethane)s. Postpolymerization click chemistry strategy is applied to make well-defined amphiphilic one-dimensional rodlike and three-dimensional spherical polymer brushes by merely varying the lengths of PEG-azides in the reaction. These core-shell polymer brushes are found to be nontoxic and nonhemolytic and capable of loading clinical anticancer drug doxorubicin and deep-tissue penetrable near-infrared biomarker IR-780. In vitro enzymatic drug-release kinetics and lysotracker-assisted real-time live-cell confocal bioimaging revealed that the rodlike polymer brush is superior than its spherical counterparts for faster cellular uptake and enzymatic biodegradation at the endolysosomal compartments to release DOX at the nucleus. Further, in vivo live-animal bioimaging by IVIS technique established that the IR-780-loaded rodlike polymer brush exhibited efficient deep-tissue penetration ability and emphasized the importance of polymer brush topology control for biological activity. Polymer brushes exhibit good stability in the blood plasma for more than 72 h, they predominately accumulate in the digestive organs like liver and kidney, and they are less toxic to heart and brain tissues. IVIS imaging of cryotome tissue slices of organs confirmed the deep-penetrating ability of the polymer brushes. The present investigation opens opportunity for bioderived and biodegradable polymer brushes as next-generation smart drug-delivery scaffolds.

Interfacial blending in co-axially electrospun polymer core-shell fibers and their interaction with cells via focal adhesion point analysis

Electrospun polymer scaffolds have gained prominence in biomedical applications, including tissue engineering, drug delivery, and wound dressings, due to their customizable properties. As the interplay between cells and materials assumes fundamental significance in biomaterials research, understanding the relationship between fiber properties and cell behaviour is imperative. Nevertheless, altering fiber properties introduces complexity by intertwining mechanical and surface chemistry effects, challenging the differentiation of their individual impacts on cell behaviour. Core-shell fibers present an appealing solution, enabling the control of mechanical properties of scaffolds, flexibility in material and drug selection, efficient encapsulation, strong protection of bioactive drugs against harsh environments, and controlled, prolonged drug release. This study addresses a key challenge in core-shell fiber design related to the blending effect between core and shell polymers. Two types of fibers, PMMA and core-shell PC-PMMA, were electrospun, and thorough analyses confirmed the desired core-shell structure in PC-PMMA fibers. Surface chemistry analysis revealed PC diffusion to the PMMA shell of the core-shell fiber during electrospinning, subsequently prompting an investigation of the fiber’s surface potential. Conducting cellular studies on osteoblasts by super-resolution confocal microscopy provided insights into the direct influence of interfacial polymer blending and, consequently, altered fiber surface and mechanical properties on cell focal adhesion points, bridging the gap between material attributes and cell responses in core-shell fibers.

Ultrasound generation in water via quasi-periodically snapping polymeric core–shell micro-bead excited with radiowaves

This work reports the results of a theoretical and numerical study showing the occurrence of stochastically resonating bistable dynamic in polymeric micro-bead of sub-micrometric size with stiff core and soft shell. The system, submerged in water, is excited with a pulsed laser working in the Mega-Hertz frequency range and tuned to match both an optical and acoustic resonance of the system. The laser interacts with the carbon nanotubes embedded in the shell of the polymeric micro-bead generating heat. The concurrent action of the generated heat with the standing acoustic oscillations, gives rise to a stochastically resonating bistable system. The system in fact is forced to switch between two states (identifiable with the creation and organized disruption of a quasi-hexagonal tessellation) via a snap-through-buckling mechanism. This phenomenon results in the unprecedented generation of pressure oscillations. These results open the way to develop a new type of core–shell micro-transducers for radioacoustic imaging applications able to work in the Mega-Hertz frequency range. From a more general thermodynamic perspective, the reported mechanism shows a remarkable periodicity and energy conversion efficiency.

Fast and Straightforward Synthesis in Molecular Imprinting: Core–Shell Polymerization of Magnetic Imprinted Polymers by Microwave Induction

Fast and Straightforward Synthesis in Molecular Imprinting: Core–Shell Polymerization of Magnetic Imprinted Polymers by Microwave Induction

Tunable self-assembly of lipid-based block polymeric micelles with temperature-sensitive poly(vinylcaprolactam) shell for effective anticancer drug delivery

Lipids, as naturally occurring biomolecules have emerged as promising carriers for delivering various therapeutic agents. However, only a few attempts have been made in terms of their applications as amphiphilic block copolymers for anticancer drug delivery. In this work, a biocompatible micellar drug delivery system with fatty acid-based polymer core and temperature-sensitive shell was developed. A series of amphiphilic block copolymers poly(vinyl stearate)/poly(vinyl laurate)-b-poly(N-vinylcaprolactam) (PVS/PVL-b-PNVCL) were synthesized via microwave-assisted reversible addition-fragmentation chain transfer polymerization in a controlled fashion. By varying the fatty acid type and hydrophilic/hydrophobic block lengths, the self-assembly behaviour of the block copolymer micelles proved to be highly tunable in terms of their morphology and particle size. Nile Red and hydrophobic anticancer drug doxorubicin (DOX) were effectively incorporated into the micelles, demonstrating high drug loading capacity, good serum stability, and temperature-dependent drug release characteristics of the polymeric micelles. In vitro studies using cell models revealed that blank PVS -b-PNVCL micelles are biocompatible with different cell lines, while DOX-loaded micelles were internalized into and accumulated in the cells, showing a high cytotoxic effect against HeLa cells. These findings suggest an opportunity for the development of safe and efficient lipid-based micellar system for smart drug delivery and cancer treatments.

In situ PET-RAFT polymerization to prepare guanidine-and-carbohydrate modified ZnO nanoparticles

ZnO–polymer core–shell nanoparticles were successfully prepared using a simple in situ open-to-air PET-RAFT method.

Catechol-formaldehyde resin microspheres@UiO-66-NH2@ CdS core-shell nanohybrids as robust visible-light photocatalyst for multifunctional applications

Well-defined zirconium based metal-organic frameworks (MOFs) coated polymer core-shell nanohybrid (CFR@MOF) was constructed using catechol formaldehyde resin (CFR) microspheres as a support, followed by encapsulating CdS nanoparticles (NPs) into MOF (UiO-66-NH2) shell layers to obtain CFR@UiO-66-NH2@CdS nanohybrids to enhance visible photosensitization for multifunctional photocatalytic applications including organic pollutant degradation, water disinfection and photoinduced atomic transfer radical polymerization (photoATRP). The CFR microspheres with a regular spherical morphology (200–400 nm) provided a versatile initial platform for the growth of MOF shells through mononuclear coating. The impact of different loadings of CdS NPs incorporated into CFR@UiO-66-NH2 shells on photocatalytic performance was systematically investigated. CFR@UiO-66-NH2 @CdS demonstrated robust dye degradation and antibacterial ability. Especially, a remarkable inhibitory efficiency of 99.99 % and 99.7 % was achieved for S. aureus and E. coli, with a low photocatalyst dosage (100 μg/mL) under visible light. Furthermore, by combining CFR@UiO-66-NH2@CdS with CuBr2/L catalysts, a high-efficiency red-light triggered photoredox catalytic polymerization system was established in photoinduced atom transfer radical polymerization (photoATRP), achieving high conversion rate (>90 %) for various monomers in a short time.

Preparation of PAN@PU coaxial electrostatic spun nanofibers for oil/water separation

AbstractCoaxial electrostatic spinning (co‐electrostatic spinning) technology has greatly expanded the versatility of the preparation of core–shell polymer nanofibers and has found a wide range of applications in the environmental and biological fields. Here we present a method for the preparation of coaxial nanofibers using polyacrylonitrile (PAN) and polyurethane (PU) as raw materials. It was found that the tensile strength ranges from 2.14 to 4.07 MPa with the increasing spinning speed of the nucleated PU layer, and the elongation at break was up to 95.09% for M6:4, which was three times higher than that of the original MPAN (30.54%), and the toughness of the nanofiber film was also significantly improved. Finally, the oil/water separation capacity of the coaxial nanofiber membrane was investigated, and the results showed that the separation fluxes for various oil compounds ranged from 2380.18 to 3130.17 L·m−2·h−1, with separation efficiencies above 99%. This study not only investigates the effect of different flow rates of core (PU)/shell (PAN) on the performance of coaxial electrostatic spun nanofiber membranes, but also provides a new insight into the coaxial electrostatic spinning process.

Polydopamine modified heteropolyacids catalyst for methacrolein oxidation: Organic ammonia functionalized and regulation of morphology

The oxidation of methacrolein (MAL) to methacrylic acid (MAA) catalyzed by Keggin-type phosphomolybdovanadic acid catalyst belongs to the acid-catalyzed and oxygen-catalyzed co-promoted reactions. It is a challenge to design catalysts with suitable acidity and redox properties. In this paper, a strategy using organic ammonia to modify CsH3PMo11VO40 (CsPAV) was proposed. Core-shell polymerization precursors were synthesized by using polydopamine (PDA) microspheres as modifiers and templates, and regularly arranged PDA-CsPAV bowl-shaped catalysts were obtained via one-step calcination. The morphology, structure, thermal stability, acidity and redox properties of PDA-CsPAV catalysts were characterized by XRD, FT-IR, TG-DTA, XPS, SEM, H2-TPR and NH3-TPD, and the catalytic performance was evaluated by oxidation of MAL to MAA. The rich functional groups on the surface of PDA microspheres combine with H4PMo11VO40 (HPAV) through strong coordination bonds to form a catalyst film. The uniform spherical structure of PDA can adjust the dispersion and morphology of CsPAV. NH4+ was formed and rearranged with heteropoly anions during calcination, which positively regulated the acidity and redox property of the catalyst. The addition of PDA accelerated electron transfer and strengthened the self-reduction process of HPAV. Compared with CsPAV, PDA-CsPAV has more acid sites and oxidation catalytic active centers (VO2+), thus exhibiting better MAL oxidation performance and good thermal stability.

Membrane fouling monitoring by 3ω sensing

Membrane fouling significantly reduces membrane permeability, leading to higher operational expenses. In situ monitoring of membrane fouling can potentially be used to reduce operation cost by optimizing operational parameters and cleaning conditions. In this study, a platinum wire with a diameter of 20 µm was attached to the surface of a ceramic ultrafiltration membrane, and by measuring the voltage across the wire while applying an AC current, the amplitude of the third harmonic wave, the so-called 3ω signal, was obtained. Results showed increasing 3ω signals during formation of fouling layers, which correlates directly to the hydraulic resistance of the formed fouling layer in semi-dead end filtration of polymeric core shell particles and crossflow filtration of diluted milk. This is explained by the insulating effect of the fouling layers which reduces heat convection by crossflow and the different thermal conductivity in the fouling layer compared with the feed. After membrane cleaning, the permeability and the magnitude of the 3ω signal were partly restored, showing that the 3ω method can be used to monitor the effect of cleaning. The frequency of the AC current was varied so it was possible to measure the heat conductivity in the fouling layer (high frequency) and heat convection due to cross-flow (low frequency). This may potentially be used to get information of the type of fouling (heat conductivity) and thickness of the fouling layer (AC frequency where heat conductivity becomes dominating).

Numerical Simulation and Comparison of the Mechanical Behavior of Toughened Epoxy Resin by Different Nanoparticles.

Adding nanoparticles as the second phase to epoxy can achieve a good toughening effect. The aim of this paper is to simulate the toughening behavior of epoxy resin by different nanoparticles using a convenient and effective finite element method. The mechanical behaviors of epoxy resins toughened by nano core-shell polymers, liquid rubber, and nanosilica were compared by numerical simulations using the representative volume element (RVE). It is indicated that the addition of a nano core-shell polymer and liquid rubber can reduce the tensile properties of epoxy resin, while nanosilica is on the contrary. With the increase of nanoparticle content, the length of crack propagation decreases, and the toughening effect of the nano core-shell polymer is the best. The failure mode is determined by the particle/matrix interface when the modulus of the nanoparticle is much larger than that of epoxy resin. However, it is determined by the interface properties of the particle/matrix and the modulus of nanoparticles in other cases. The results provide a theoretical basis for toughening nanoparticle selection of nanoparticle-toughened epoxy resin and other similar simulations in the future.

Hydratable Core-Shell Polymer Networks for Atmospheric Water Harvesting Powered by Sunlight.

The development of technologies to enable fresh water harvesting from atmospheric moisture could help overcome the problem of potable water scarcity. Here, an atmospheric water harvesting (AWH) device is assembled in a core-shell structure, with the core consisting of networks of alginate (Alg) and polyaniline (PANI) and the outer layer consisting of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) modified with sulfonic acid groups (SPNIPAM) to increase the water adsorption at low relative humidity. The resulting hydrogel, modified with lithium chloride (LiCl) for increased water storage capacity (SPNIPAM-Li-PANIAlg), displays a similar lower critical solution temperatureto pristine PNIPAM (32 °C) while affording a 15-fold higher water capture ratio, and releases water upon exposure to sunlight at intensities less than 1kW m-2 . The developed AWH system is capable of harvesting 6.5 L of water per kilogram in a single daily absorption/desorption cycle under sunlight and can operate at relative humiditylevels as low as 17% with no additional external energy input. The thermo-responsive hydrogel SPNIPAM-Li-PANIAlg exhibits excellent stability during natural sunlight-driven absorption/desorption cycles for at least 30 days, and allows sustainable harvesting of over 28.3 L kg-1 from a moisture-rich environment by means of multiple absorption/desorption cycles.

Mapping the low abundant plasma glycoproteome using Ranachrome-5 immobilized magnetic terpolymer as improved HILIC sorbent

HILIC (hydrophilic interaction liquid chromatography) materials enrich glycopeptides. The non-specific interactions because of support material and inadequate hydrophilicity render loss of less abundant glycopeptides in SPE-based enrichments. In this work, magnetic terpolymer (Fe3O4@MAA/DVB/1,2-Epoxy-5-hexene) is functionalized with Ranachrome-5 to generate enhanced hydrophilicity. Amine, carboxylic, and amide groups of ranachrome-5 provide zwitterionic chemistry. Material’s magnetic core contributes to ease of operation while higher surface area 97.0711 m2 g−1 immobilizes better quantities of Ranachrome-5. Homogeneous morphology, nano-size, and super hydrophilicity enhance enrichment. Ranachrome-5 functionalized polymeric core-shell beads enrich 25, 18 and 16 N-linked glycopeptides via SPE strategy from tryptic digests of model glycoproteins i.e., immunoglobulin G (IgG), horseradish peroxidase (HRP) and chicken avidin, respectively. Zwitterionic chemistry of ranachrome-5 helps in achieving higher selectivity (1:250, HRP / Bovine Serum Albumin), and lower detection limit (100 attomole, HRP digest) with complete glycosylation profile of each standard digest. High binding capacity (137.1 mg/g) and reuse of affinity material up to seven cycles reduce the cost and amount of affinity material for complex sample analysis. A recovery of 91.76% and relative standard deviation (RSD) values less than 1 define the application of HILIC beads for complex samples like plasma. 508 N-linked intact low abundant glycopeptides corresponding to 50 glycoproteins are identified from depleted human plasma samples via nano-Liquid Chromatography-Tandem Mass Spectrometry (nLC-MS/MS). Using Single Nucleotide Variances (BioMuta) for low abundant plasma glycoproteins, the potential association of proteins to four cancers, i.e., breast, lung, uterine, and melanoma is evaluated. Via the bottom-up approach, HILIC beads can analyze clinically important low-abundant glycoproteins.

Broad spectral photodetectors based on BiOCl@boronate polymer core-shell heterojunctions

BiOCl has been actively explored as a promising material for photodetectors (PDs), but inefficient charge separation and narrow response spectral range limit the further development of BiOCl-based PDs. Herein, we show that coating BiOCl with a boronate polymer (BP) shell may provide a simple route to overcome the above limitations. The migration of Bi3+ from BiOCl to BP changes the energy level and enhances the light absorption of BP shell. Violent coordination at the core–shell interface, as well as Bi3+ migration induces the generation of Bi3+-O·-Bi3+ defects. Also, BP shell can reduce the darkcurrent of BiOCl@BPs PDs. The optimized PD assembled with BiOCl@BP1.9 (the subscript represents the shell thickness) shows fast photoresponse (rise time: 32, decay time: 52 ms, respectively), high on/off ratio, and responsivity of 119.77 μA/W under 365 nm light at 15 V. Moreover, BiOCl@BP PDs exhibit a gradually broadened spectral response range with the increase of BP shell thickness and show much higher photodetection performances. For example, under 940 nm light stimulation, the optimized PD (BiOCl@BP20.1) exhibits a high responsivity of 22.18 μA/W, 28 times that of BP PD. Our findings may provide a guideline for the design of high-performance PDs based on the precise construction of polymer-inorganic heterostructures.

A ROS-response hyaluronic acid-coated/chitosan polymer prodrug for enhanced tumour targeting efficacy of SN38

Ethyl-10-hydroxycamptothecin (SN38) is a camptothecin derivative with significant anti-tumour therapeutic potential, while the clinical application of SN38 was limited by its poor water solubility and low stability. Herein, a core-shell polymer prodrug hyaluronic acid @chitosan-S-SN38 (HA@CS-S-SN38) was designed by CS-S-SN38 as the core and the HA as the shell, which aims to overcome the limitations of the clinical application of SN38, while realising the high tumour targeting of polymer prodrug and the controllable release of drug in tumour cells. HA@CS-S-SN38 showed the high responsiveness of the tumour microenvironment and the safe stability of blood circulation. Furthermore, HA@CS-S-SN38 exhibited the begin uptake efficiency and favourable apoptosis in the 4T1 cells. More importantly, compared with irinotecan hydrochloride trihydrate (CPT-11), HA@CS-S-SN38 significantly improved the conversion efficiency of the prodrug to SN38, and showed excellent tumour targeting and retention in vivo by combining passive and active targeting strategies. In tumour-bearing mice treatment, HA@CS-S-SN38 showed the perfect anti-tumour effect and therapeutic safety. These results indicated that the polymer prodrug designed by ROS-response/HA-modification strategy is a safe and efficient drug delivery system, which provides a new idea for clinical utilisation of SN38 and warrants further evaluation.