Polymer Composite Microspheres Research Articles

Extending Polymer Opal Structural Color Properties into the Near-Infrared

We report the fabrication and characterisation of near-IR reflecting films and coatings based on shear-assembled crystalline ensembles of polymer composite microspheres, also known as “polymer opals”. Extension of the emulsion polymerisation techniques for synthesis of tractable larger core-interlayer-shell (CIS) particles, of up to half a micron diameter, facilitates the engineering and processing of thin-film synthetic opals, with a tunable photonic stopband spanning an extended spectral range of λ ≈ 700–1600 nm. Samples exhibit strong “scattering cone” interactions, with considerable angular dependence and angle tuning possible, as measured with a goniometric technique. These intense optical resonances in the near-IR, particularly within the important region around λ ~ 800 nm, combined with an appreciable translucency within the visible light spectrum, is indicative of the potential applications in coatings technologies and solar cells.

Carboxyl-Assisted Coordination-Driven Self-Assembly for the Preparation of Magnetic Polymer Composite Microspheres

Carboxyl-Assisted Coordination-Driven Self-Assembly for the Preparation of Magnetic Polymer Composite Microspheres

Research Progress on the Preparation of Inorganic/Natural Materials Composite Microspheres

Microspheres are a new type of drug carrier with great potential for development and application. Natural polymers have good biocompatibility, biodegradability, and are easily dispersed in living organisms, making them suitable for preparing microspheres. Inorganic materials (mainly inorganic minerals) have excellent mechanical properties and are inexpensive and easy to obtain. Through the coupling and hybridization of natural polymers and inorganic materials, they can complement each other's advantages and synergistically enhance efficiency, resulting in many excellent physical and chemical properties. Inorganic materials/natural polymer composite microspheres can be prepared by modifying natural polymers with inorganic materials through various methods such as emulsification crosslinking, solution mixing, in-situ synthesis, extrusion, etc. The application of inorganic materials/natural polymer composite microspheres in drug delivery systems has significant sustained-release effects, is safe and non-toxic, and the cost of carrier materials is relatively low, which has certain significance for the development of new drug carriers. This article reviews the recent research on the preparation, drug loading and release properties of inorganic material/natural polymer composite microspheres, analyzes the advantages and disadvantages of commonly used preparation methods, and looks forward to the development direction of composite microspheres.

Polymer composite microspheres loading 177Lu radionuclide for interventional radioembolization therapy and real-time SPECT imaging of hepatic cancer

BackgroundTransarterial radioembolization (TARE) with 90Y-labeled glass and resin microspheres is one of the primary treatment strategies for advanced-stage primary and metastatic hepatocellular carcinoma (HCC). However, difficulties of real-time monitoring post administration and embolic hypoxia influence treatment prognosis. In this study, we developed a new biodegradable polymer microsphere that can simultaneously load 177Lu and MgO nanoparticle, and evaluated the TARE therapeutic efficacy and biosafety of 177Lu-PDA-CS-MgO microspheres for HCC treatment.MethodsChitosan microspheres were synthesized through emulsification crosslink reaction and then conducted surface modification with polydopamine (PDA). The 177Lu and nano MgO were conjugated to microspheres using active chemical groups of PDA. The characteristics of radionuclide loading efficiency, biodegradability, blood compatibility, and anti-tumor effectwere evaluated both in vitro and in vivo. SPECT/CT imaging was performed to monitor bio-distribution and bio-stability of 177Lu-PDA-CS-MgO after TARE treatment. The survival duration of each rat was monitored. HE analysis, TUNEL analysis, immunohistochemical analysis, and western blot analysis were conducted to explore the anti-tumor effect and mechanism of composited microspheres. Body weight, liver function, blood routine examination were monitored at different time points to evaluate the bio-safety of microspheres.ResultsThe composite 177Lu-PDA-CS-MgO microsphere indicated satisfactory degradability, biocompatibility, radionuclide loading efficiency and radiochemical stability in vitro. Cellular evaluation showed that 177Lu-PDA-CS-MgO had significant anti-tumor effect and blocked tumor cell cycles in S phase. Surgical TARE treatment with 177Lu-PDA-CS-MgO significantly prolonged the medial survival time from 49 d to 105 d, and effectively inhibited primary tumor growth and small metastases spreading. Moreover, these microspheres indicated ideal in vivo stability and allowed real-time SPECT/CT monitoring for up to 8 weeks. Immunostaining and immunoblotting results also confirmed that 177Lu-PDA-CS-MgO had potential in suppressing tumor invasion and angiogenesis, and improved embolic hypoxia in HCC tissues. Further evaluations of body weight, blood test, and pathological analysis indicated good biosafety of 177Lu-PDA-CS-MgO microspheres in vivo.ConclusionOur study demonstrated that 177Lu-PDA-CS-MgO microsphere hold great potential as interventional brachytherapy candidate for HCC therapy.Graphical Polymer composite microspheres loading 177Lu radionuclide and MgO nanoparticles for interventional radioembolization therapy and real-time SPECT imaging of hepatic cancer.

Controlled long-term sustained release of poly(lactic acid) composite microspheres with dual-responsive cellulose nanocrystals

This work represents dual-responsive polylactide composite microspheres with potential multifunctional drug delivery systems for promising medical applications.

Preparation of hydrophobic and high‐strengthpolymer microspheres based on constructing a “Functionalmonomer‐St‐DVB” copolymer structure:Ultra‐low‐densityproppants

AbstractUltra‐low‐density proppants are of great significant in slick water fracturing system, but the polymer composite microspheres can hardly promise the quality of oil and gas due to their poor hydrophobicity. To address the issue, we prepared several types of modified styrene‐divinyl benzene copolymer microspheres (MSDBs) with long‐term durable hydrophobicity and high strength, including O‐MSDBs (hydrophobic MSDBs), LO‐MSDBs (long‐time hydrophobic MSDBs), and CO‐MSDBs (coated O‐MSDBs) on the basis of a molecular structure of “KH570‐styrene (St)‐divinyl benzene (DVB)” copolymer. In this article, the design concept and the structure of MSDBs was clarified, and performances of MSDBs are systematically discussed and compared with commercially available hydrophobic microspheres. The O‐MSDBs, a kind of nanoparticle patterned St‐DVB copolymer microspheres, were prepared by a one‐step suspension polymerization undergoing a sol–gel process, showing strong hydrophobicity with a water contact angle up to 140.7°, but short durability in strong hydrochloric acid or hydrofluoric acid; On the contrary, LO‐MSDBs perform better in the stability and durability of hydrophobicity with a slightly lower water contact angle about 135.9°. The LO‐MSDBs were designed by coating functionalized St‐DVB copolymer microspheres with fluororesin. Similarly, CO‐MSDBs from fluororesin‐coated O‐MSDBs were designed. As expected, CO‐MSDBs have a stronger hydrophobicity (139.0°) than LO‐MSDBs and longer durability than O‐MSDBs. Moreover, the MSDBs exhibit better properties than the commercially available hydrophobic polymer and ceramic microspheres.

Preparation, characterization and molecular dynamics of novel pre-plasticized nitrocellulose composite microspheres containing burning rate catalysts

ABSTRACT In this contribution, pristine nitrocellulose (NC) and novel NC/glycidyl azide polymer (GAP) composite microspheres with uniformly dispersed burning rate catalysts, a high degree of roundness and excellent fluidity, were successfully prepared using a solution blending procedure. The burning rate catalysts had an apparent catalytic effect on the thermal decomposition of the novel composite microspheres and promoted their heat release. Furthermore, molecular dynamics simulation was conducted to explore the plasticizing mechanism of GAP. NC/GAP showed improvements in free volume and radius of rotation of 82.14% and a 50.13%, respectively, compared to pristine NC, indicating that GAP molecules had increased mobility in the NC matrix. In addition, the radial distribution function showed that NC/GAP exhibited higher intermolecular intensities from both hydrogen bonding and van der Waals forces compared to those of pristine NC, which was consistent with the value obtained for the average intermolecular interaction energy. The experimental and computational studies showed that there may be good potential for the design and manufacture of novel pre-plasticized NC composite microspheres having low vulnerability and good plasticizing performance for preparation of propellant.

Preparation and Catalytic Performance of Microporous Polymer/Au Nanoparticles Composite Microspheres

Polystyrene crosslinked microspheres were prepared by soap-free emulsion polymerization using styrene (St) and divinylbenzene (DVB) as monomers; then, the microporous structure was knitted by the Friedel-Crafts alkylation reaction, and the Au nanoparticles (AuNPs) were loaded into the pores through thermal reduction, to obtain AuNPs/hyper-crosslinked microporous polymer composite microspheres. SEM and particle-size test results show that the microspheres show good monodispersity. The micropore analysis indicates that the specific surface area and the pore volume of the microporous polymer microspheres decrease with increasing DVB content, and when the DVB content is 0.1%, the specific surface area reaches a maximum of 1 174.6 m2/g. After loading AuNPs, the specific surface area and the amount of micropores of the composite microspheres decrease obviously. The results of XRD and XPS analyses suggest that HAuCl4 is reduced to AuNPs. The composite microspheres show a good catalytic performance for the reduction catalyst of 4-nitrophenol.

Self-assembly of colloidal Poly(St-MMA-AA) core/shell photonic crystals with tunable structural colors of the full visible spectrum

This study used the copolymer emulsion method to synthesize colloidal monodisperse core/shell microspheres composed of the poly(styrene-co-methyl methacrylate-co-acrylic acid) [Poly(St-MMA-AA)]. Colloidal photonic crystal (CPhC) films have prepared by using polymer composite microspheres and successfully fabricated via natural sedimentation. The synthesized results of polymer composite microsphere exhibited uniform and good morphology. The resultant of CPhC color films demonstrated vividly structural colors due to 3D CPhC nanostructures. The structural colors over full visible spectra could be tuned by controlling the filling factor of crystals and diameter of microspheres according to the Bragg law. Additionally, the structural color of Poly(St-MMA-AA) CPhC films has measured under the standard colorimetric system. This study demonstrated a approach to fabricate tunable structural color for numerous applications.

Fabrication of Alkoxyamine-Functionalized Magnetic Core-Shell Microspheres via Reflux Precipitation Polymerization for Glycopeptide Enrichment.

As a facile method to prepare hydrophilic polymeric microspheres, reflux precipitation polymerization has been widely used for preparation of polymer nanogels. In this article, we synthesized a phthalamide-protected N-aminooxy methyl acrylamide (NAMAm-p) for preparation of alkoxyamine-functionalized polymer composite microspheres via reflux precipitation polymerization. The particle size and functional group density of the composite microspheres could be adjusted by copolymerization with the second monomers, N-isopropyl acrylamide, acrylic acid or 2-hydroxyethyl methacrylate. The resultant microspheres have been characterized by TEM, FT-IR, TGA and DLS. The experimental results showed that the alkoxyamine group density of the microspheres could reach as high as 1.49 mmol/g, and these groups showed a great reactivity with ketone/aldehyde compounds. With the aid of magnetic core, the hybrid microspheres could capture and magnetically isolate glycopeptides from the digested mixture of glycopeptides and non-glycopeptides at a 1:100 molar ratio. After that, we applied the composite microspheres to profile the glycol-proteome of a normal human serum sample, 95 unique glycopeptides and 64 glycoproteins were identified with these enrichment substrates in a 5 μL of serum sample.

Superparamagnetic polymer composite microspheres supported Schiff base palladium complex: An efficient and reusable catalyst for the Suzuki coupling reactions

Superparamagnetic polymer composite microspheres Fe3O4/P(GMA-AA-MMA) prepared by soap free emulsion polymerization were used to support Schiff base palladium complex. Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), X-ray photoelectronic spectrography (XPS) and thermal gravity (TG) studies have been used to characterize the supported magnetic Schiff base catalyst. The magnetic catalyst could provide excellent reactivity in the Suzuki coupling reactions of aryl halides with phenylboronic acids under mild condition. Meanwhile, the supported magnetic catalyst acted as a true heterogeneous catalyst in the Suzuki coupling reactions. Furthermore, the novel catalyst could be conveniently recovered by an external magnet and reused at least seven times without significant loss of its catalytic activity or Pd leaching.

Switchable dispersivity and molecular-trapping performance of mesostructured CaCO3-thermosensitive polymer composite microspheres.

Monodispersed thermosensitive microspheres were synthesized by the combination of poly(N-isopropylacrylamide) (PNIPAAm) and a mesostructured framework consisting of vaterite CaCO3 nanocrystals ∼20 nm in diameter. The switchable dispersivity in water and organic media was provided to the rigid porous framework by the soft shell of the thermosensitive organic component. The microspheres were shuttlecocked between water and hydrophobic organic media by a swing in temperature across the lower critical solution temperature (LCST). The composite microspheres performed as an active carrier of organic molecules due to their switchable property. Hydrophobic molecules were captured by the microspheres dispersed in an organic medium above LCST and were then delivered and released to another organic phase through a water phase by a swing in temperature.

Nanosized palladium supported on diethylenetriamine modified superparamagnetic polymer composite microspheres: Synthesis, characterization and application as catalysts for the Suzuki reactions

Superparamagnetic polymer composite microspheres Fe3O4/P(GMA-AA-MMA) prepared by an emulsifier free emulsion polymerization using DPE as free radical control agent were used to support palladium nanoparticles. The magnetic catalyst can provide excellent reactivity in the Suzuki coupling reactions of aryl halides with phenylboronic acids under mild condition (at 80°C) in EtOH/H2O (1:1) mixture. Furthermore, the novel catalyst can be conveniently recovered by an external magnet field and reused at least five times without significant loss of its catalytic activity.

Preparation of polymer hollow microspheres covered by polymer solid particles via two polymerization steps

AbstractA novel surface modification method for titania nanoparticles is provided via the surface‐initiated photocatalytic polymerization with the aid of acrylic acid (AA) or sodium styrene sulfonate (NaSS). The properties of modified titania nanoparticles are investigated with aqueous electrophoresis measurements, dynamic light scattering (DLS), and transmission electron microscopy (TEM). Then the modified titania is used as Pickering stabilizer for further polymerization and the morphology of the resulted polymer microspheres is characterized by TEM and field‐emission scanning electron microscopy. It is proven that the addition of AA or NaSS for the surface‐initiated polymerization can obviously affect the structure and morphology of the final polymer composite microspheres. The formation mechanism of several kinds of polymer particles is also proposed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Lipid–polymer composite microspheres for colon-specific drug delivery prepared using an ultrasonic spray freeze-drying technique

Lipid–polymer composite microspheres (LP-MS) for colon-specific drug delivery were prepared using an ultrasonic spray freeze-drying technique. These microspheres, which consist of the pH-sensitive polymer Eudragit S100 and the non-polar lipid Compritol 888 ATO, were characterized by morphological and physicochemical properties. It was found that the LP-MS have a spherical lipid porous matrix with a smooth pH-sensitive polymer film on both internal and external surfaces, and the insoluble drug 10-hydroxycamptothecin was dispersed in an amorphous state in the carrier. Morphological changes of microparticles under different pH conditions were observed by confocal laser scanning microscopy, which showed that the lipid matrix in LP-MS restricted the swelling property of the polymer at pH 6.8. In drug release studies, less than 15% of the drug was released below pH 6.8, whereas more than 30% was released with a sustained-release model at pH 7.4. The LP-MS could provide a promising vehicle for colon drug delivery.

Versatile fabrication of water-dispersible nanoparticle–amphiphilic copolymer composite microspheres with specific functionalities

In this paper, we demonstrated a versatile approach for fabricating water-dispersible nanoparticle (NP)–polymer composite microspheres from amphiphilic poly(ethylene glycol) diglycidyl-grafted poly(maleic anhydride-alt-octadecene) (PMAO-g-PEG) and various NPs with specific functionalities. Depending on the surface polarity of the NPs, the microspheres were fabricated either via two step phase transfers for water soluble NPs or one step phase transfer for oil-soluble ones. For example, aqueous luminescent CdTe NPs were first transferred to chloroform by dimethyldioctadecylammonium bromide modification, and subsequently transferred back to water using PMAO-g-PEG, thus producing luminescent microspheres. Due to the protection of the polymer, the luminescence stability of the NPs under acidic conditions was significantly improved, permitting the detection of Ag+ and Cu2+ over a broader pH range.

Monodisperse magnetic composite poly(glycidyl methacrylate)/La0.75Sr0.25MnO3 microspheres by the dispersion polymerization

Monodisperse magnetic poly(glycidyl methacrylate) microspheres were prepared by dispersion polymerization of glycidyl methacrylate in cyclohexane in the presence of La0.75Sr0.25MnO3 nanoparticles, surface of which was modified with penta(propylene glycol) methacrylate phosphate (PPGMAP). However, only agglomerates were formed by the dispersion polymerization in toluene. Sterical stabilizer was poly(styrene-block-hydrogenated butadiene-block-styrene) and initiators investigated were 2,2′-azobisisobutyronitrile (AIBN) and 4,4′-azobis(4-cyanovaleric acid) (ACVA). Effects of initiators and other reaction conditions on properties of the composite microspheres were evaluated. The phase composition of the magnetic polymer composite microspheres and the size of magnetic cores were determined by X-ray powder diffraction. The characterization was completed by magnetization measurements, atomic absorption spectroscopy, TEM, SEM and ATR FTIR spectroscopy.

Synthesis of TiO<sub>2</sub>/Polymer Composite Microspheres Using Functional Porous Polymer Particle as Substrate

This study described a different nano-titania(TiO2)/polymer composite where TiO2 were uniformly deposited on the porous poly(styrene-divinyl benzene-co-maletic anhydride) [poly(st-DVB-co-MAH)] microspheres. The morphology of the composite microspheres was analyzed by scanning electron microscope and X-ray diffraction. Both the diameter of the pore and the MAH functional groups played a crucial role in controlling the structure of TiO2 shell. The rutile nanoparticles were incorporated evenly onto the surface of the porous microspheres when microspheres with pore diameter of about 146.8 nm and with surface 30 wt% functional groups (MAH) were used as substrate.

Synthesis of tetra-layer polymer composite microspheres and the corresponding hollow polymer microspheres with Au nanoparticles functionalized movable cores

Hollow poly(ethyleneglycol dimethacrylate) (PEGDMA) microspheres with Au nanoparticle functionalized movable cores were prepared by selective removal of the sandwiched silica mid-layer from the corresponding poly(ethyleneglycol dimethacrylate-co-methacrylic acid)/poly(ethyleneglycol dimethacrylate-co-vinylpyridine)@gold/silica/PEGDMA (P(EGDMA-co-MAA)/P(EGDMA-co-VPy)@Au/SiO2/PEGDMA) tetra-layer composite microspheres, in which the Au nanoparticles were stabilized by the pyridyl groups on the surface and gel-layer of P(EGDMA-co-MAA)/P(EGDMA-co-VPy) particles during the reduction of HAuCl4 with sodium borohydride. The tetra-layer polymer composite microspheres were synthesized via the combination of distillation precipitation polymerization for the preparation of the polymer core and outer shell layer together with the modified Stober sol–gel process for the formation of the sandwiched silica mid-layer. The primary results indicated that the Au nanoparticle functionalized movable cores enabled the hollow polymer microspheres to act as efficient catalysts for the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride as the reductant.

Preparation of poly(styrene–glucidylmethacrylate)/Fe 3O 4 composite microspheres with high magnetite contents

Magnetic polymer composite microspheres with high magnetite contents were prepared by dispersion polymerization of styrene (St) and glucidylmethacrylate (GMA), in which Fe 3O 4 nanoparticles were co-stabilized by oleic acid and silane surfactants. The microstructure of the composite microspheres was characterized by Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results demonstrated the presence of a hybrid morphology with organic polymer-encapsulated inorganic particles. Subsequently, thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM) were used to evaluate the magnetite content of the microspheres. It was found that an accordant magnetite content of about 70 wt%, could be obtained for the magnetic polymer microspheres, a value significantly higher than those reported thus far. The possible mechanism for the formation of the microspheres was proposed.