One-step Miniemulsion Polymerization Research Articles

Synthesis and characterization of photochromic polyurethane nanoparticles by miniemulsion polymerization

As an organic photochromic material, spiropyran (SP) has attracted extensive attention due to its rapid and reversible color switching under specific wavelength irradiation. However, the molecular packing during SP isomerization and the influence of external solvents lead to unstable photochromic properties, limiting its practical applications. In this study, the novel photochromic polyurethane nanoparticles were prepared by environmentally friendly materials, isophorone diisocyanate (IPDI) and sorbitan fatty acid esters (Span), through one-step miniemulsion polymerization. The nanoparticles exhibit sensitive photochromic process under UV irradiation, and after 20 UV–vis cycles, these nanoparticles retained the initial photochromic properties. Furthermore, the influence of polyurethane polymer matrix structure on the photochromic properties of SP and the decolorization rate of MC→SP isomerization process was investigated. The prepared polyurethane photochromic nanoparticles demonstrated outstanding photochromic performance and showed great potential for applications in UV-resistant fabrics, surface coatings, and photoelectric signal conversion.

Facile Fabrication of Hollow Molecularly Imprinted Polymer Latex Particles for Dibutyl Phthalate via One-step Miniemulsion Polymerization

Facile Fabrication of Hollow Molecularly Imprinted Polymer Latex Particles for Dibutyl Phthalate via One-step Miniemulsion Polymerization

Pigment printing of polyester fabric using a single step synthesized PDMS-modified polyurethane-acrylic/pigment hybrid emulsion

A novel, waterborne polydimethylsiloxane (PDMS)-modified polyurethane-acrylic (Si-PUA)/pigment hybrid emulsion was synthesized by one-step miniemulsion polymerization for the pigment printing of polyester fabric. The phase structure, hydrophobicity, and thermal and mechanical properties of the formed films with different PDMS contents from the hybrid emulsion were investigated. The results indicated that the pigment particles were uniformly distributed in the homogeneous phase polymer substrate without phase separation occurring between the PDMS phase and polyurethane-acrylic. The hydrophobicity and toughness of the Si-PUA/pigment hybrid latex films gradually increased with the increase of PDMS content. Moreover, the obtained hybrid emulsion was used as a self-curable hybrid pigment that was applied to polyethylene terephthalate fabric for pigment printing. This showed that the Si-PUA/pigment hybrid latex particles yielded similarly good values in terms of color strength, and dry- and wet-rubbing fastness to the PDMS-free hybrid latex particles. Furthermore, use of the Si-PUA/pigment hybrid latex avoided certain problems related to printed fabric, such as poor air permeability and softness.

One-step polymerized lanthanide-based polystyrene microsphere for sensitive lateral flow immunoassay

Lateral flow immunoassays (LFIAs) provide a powerful tool for rapid real-time assay of cancer biomarkers, which is vital for cancer detection and treatment follow-up. Lanthanide-based LFIAs is one of the most widely used methods, especially Eu (III) chelates, which possess distinctive and attractive characteristics, such as time-resolved fluorescence and large Stokes shift. Herein, we adopted a new one-step mini-emulsion polymerization method to synthesize carboxyl-modified fluorescent microsphere (OS-EuCM), which shows good stability, resistance to non-specific adhesion and uniform particle size distribution compared with traditional microspheres synthesized through the swelling method. Benefiting from the above advantages, OS-EuCM was successfully used in LFIAs to detect tumor marker Alpha-fetoprotein with high sensitivity and selectivity in concentration as high as 320 ng/mL, as well as a detection limit of 0.683 ng/mL. This lanthanide-based microsphere holds great potential for rapid point-of-care screening and clinical application.

Synthesis of raspberry-like SiO2/polyacrylate nanocomposite latexes via a one-step miniemulsion polymerization and its film properties

Narrowly size-distributed raspberry-like SiO2/polyacrylate nanocomposite latexes were prepared by miniemulsion polymerization. The effects of tetraethyl orthosilicate (TEOS) and γ-(methacryloxypropyl) trimethoxy silane (KH570) content on the properties of composite emulsion and films have been investigated. Dynamic light scattering (DLS) analysis showed that the narrowly size-distributed nanocomposite latexes could be prepared by the 6–10 wt% TEOS dosage and 0–2.5 wt% KH570 dosage effectively. Centrifugal stability results indicated that narrowly size-distributed composite latex particles were beneficial to the stability of composite emulsion. The formation mechanism of raspberry-like nanocomposite latex particles was proposed by measuring the morphology evolution of composite latex particles during the polymerization process. The performance analysis of nanocomposite films showed that the raspberry-like nanocomposite latexes had excellent film properties. What is more, scanning electron microscopic (SEM) analysis indicated that SiO2 nanoparticles were uniformly dispersed on surface of the composite films prepared by 10 wt% TEOS and 1.5 wt% KH570, and a good interface was established in the films.

Fabrication of self-cross-linking fluorinated polyacrylate latex particles with core-shell structure and film properties

A series of self-cross-linking fluorinated polyacrylate latex particles with core-shell structure were successfully prepared by one-step miniemulsion polymerization of methyl methacrylate (MMA), butyl acrylate (BA), dodecafluoroheptyl methacrylate (DFMA), and γ-methacryloxypropyl triisopropoxidesilane (MPS). The core-shell structure of the latex particles was confirmed and the latex films were characterized. Results showed that the latex films not only showed enhanced thermostability but also exhibited good hydrophobic property with the incorporation of a small amount of MPS (below 5wt% of monomers). This core-shell fluorine/silicone-containing polyacrylate latex could potentially be used for developing advanced multifunctional protective coatings such as antiwetting, anti-icing, antifogging, and anticorrosion.

Preparation of Epoxy-Functionalized Magnetic Polymer Nanospheres for Magnetically Targeted Radiotherapy

Magnetic poly(styrene−methyl methacrylate-glycidyl methacrylate)/Fe3O4 nanospheres with epoxy groups were prepared by modified one-step mini-emulsion polymerization in the presence of Fe3O4 ferrofluids. The products were characterized by fourier-transform infrared spectrum, transmission electron microscopy, thermogravimetric analysis and vibrating sample magnetometer. After surface modification with diaminopropane, histidine was covalently linked to the amine group of magentic nanospheres using glutaraldehyde as crosslinker. Finally, the preliminary labeling study based on non-radioactive rhenium was carried out and the labeling efficiency reached 80.4%. Such magnetic nanospheres had promising potential in magnetically targeted radiotherapy of cancer.

Facile fabrication of magnetic hybrid-shell microcapsule via miniemulsion polymerization

Magnetic hybrid-shell microcapsules were fabricated by restricting tetraethoxysilane (TEOS) phase as a liquid core due to the phase separation via one-step miniemulsion polymerization. The inner void size of magnetic hybrid-shell microcapsules could be easily tuned by adjusting the TEOS content in the miniemulsion formulation. The magnetic hybrid-shell microcapsules were characterized by FTIR, transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The results showed that magnetic hybrid-shell microcapsules had an average size of 200–600nm and the saturation magnetization values of the samples were 14.7 and 18.3emu/g. The magnetic microcapsule may provide a very promising vehicle for drug delivery, catalysis, and photoelectric materials.

A one-step miniemulsion polymerization route towards the synthesis of nanocrystal reinforced acrylic nanocomposites

The potential of starch nanoparticles (SNPs) to stabilize emulsion droplets during miniemulsion polymerization was investigated. We showed that while starch nanoplatelets were not sufficient to stabilize the monomer droplets by themselves, they did provide a synergistic stabilization effect when used together with a cationic surfactant, reducing the required surfactant amount by a factor of 4. Stabilized monomer emulsion droplets remained stable throughout the polymerization reaction and did not show any sign of Ostwald ripening. Composites obtained by film-casting the dispersions showed a markedly improved mechanical performance when compared to composite films prepared by mixing an SNP suspension with a polymer emulsion followed by film casting. Based on dynamic mechanical analysis, these improvements are the result of enhanced interactions between the polymer and the SNPs.

Fabrication of Novel Reversible Photoswitchable Fluorescent Nanoparticles

Novel photoswitchable fluorescent nanoparticles were fabricated by a facile one-step mini-emulsion polymerization, in which fluorescence resonance energy transfer (FRET) donor, 9,10-diphenylanthracene (DPA), and photoswitchable acceptor, spiropyran derivate, were simultaneously embedded in polymer matrix during the polymerization process. The prepared fluorescent nanoparticles exhibit the typical absorption properties of both DPA dye and spiropyran moiety, indicating that the two chromophores have been incorporated into the polymer nanoparticles. The obtained fluorescent nanoparticles exhibited superior photoswitchable fluorescent performance due to the effective photoinduced interparticle FRET. Moreover, the novel photoswitchable fluorescent nanoparticles also revealed small size (ca. 60 nm), high intensity, relatively fast photoresponsive property and good photoreversibility in aqueous media.

Synthesis and Characterization of Novel Reversible Photoswitchable Fluorescent Polymeric Nanoparticles via One-Step Miniemulsion Polymerization

In the present study, novel polymeric nanoparticles of ca. 55 nm in diameter with reversibly photoswitchable fluorescence properties were synthesized using a facile one-step miniemulsion polymerization, in which the donor of fluorescence resonance energy transfer (FRET), 4-methamino-9-allyl-1,8-naphthalimide (MANI), and the acceptor, spiropyran-linked methacrylate (SPMA), were covalently incorporated into a polymeric matrix during the polymerization process. The fluorescence emission of MANI dye in nanoparticles can be reversibly switched using the alternating irradiation of UV and visible light, which can induce the structural interconversion between the SP form and MC form of spiropyran moieties inside nanoparticles and thus reversibly switch on and switch off the FRET process. The prepared photoswitchable fluorescent polymer nanoparticles not only show a high load capacity of dyes, controllable amount and ratio of the two dyes, and tunable FRET efficiency but also exhibit higher spectral stability because of covalent linkage between dye molecules and the particle, relatively fast photoresponsibility, and better photoreversibility compared to some previously reported systems.

Waterborne Polyurethane−Acrylic Hybrid Nanoparticles by Miniemulsion Polymerization: Applications in Pressure-Sensitive Adhesives

Waterborne polyurethane-acrylic hybrid nanoparticles for application as pressure-sensitive adhesives (PSAs) were prepared by one-step miniemulsion polymerization. The addition of polyurethane to a standard waterborne acrylic formulation results in a large increase in the cohesive strength and hence a much higher shear holding time (greater than seven weeks at room temperature), which is a very desirable characteristic for PSAs. However, with the increase in cohesion, there is a decrease in the relative viscous component, and hence there is a decrease in the tack energy. The presence of a small concentration of methyl methacrylate (MMA) in the acrylic copolymer led to phase separation within the particles and created a hemispherical morphology. The tack energy was particularly low in the hybrid containing MMA because of the effects of lower energy dissipation and greater cross-linking. These results highlight the great sensitivity of the viscoelastic and adhesive properties to the details of the polymer network architecture and hence to the precise composition and synthesis conditions.

Fabrication of Novel Polymer Nanoparticle-Based Fluorescence Resonance Energy Transfer Systems and their Tunable Fluorescence Properties

In this study, two hydrophobic fluorescent dyes, nitrobenzoxadiazolyl (NBD) and 9-(diethylamino)benzo[a]phenoxazin-5-one (NR) with different doping ratios were incorporated into polymer nanoparticles to constitute novel polymer nanoparticle-based fluorescence resonance energy transfer (FRET) systems via a facile one-step mini-emulsion polymerization. Spectroscopic characteristics demonstrate that the two fluorophores have been successfully embedded into the nanoparticles, and the fluorescence emission intensity of the two hydrophobic dyes can be greatly enhanced in aqueous media. The as-prepared fluorescent nanoparticles also display a uniform small size (ca. 55 nm), high dye load, intense fluorescence, as well as controllable amount and ratio of the two dyes. The observed FRET efficiencies (16.0–75.2%), as well as the distance (r) between NBD (donor) and NR (acceptor), is closely correlated to the doping ratio of two dyes. Moreover, by varying the doping ratio of two dyes, the fluorescent nanoparticles would exhibit multicolor through FRET upon a single wavelength excitation, and the fluorescence emission signals of the dye-doped nanoparticles could be accurately tuned. These results indicate that the as-prepared uniform FRET-mediated nanoparticles are of high interest in multiplexed bioanalysis.

Photoluminescent properties of Prussian Blue (PB) nanoshells and polypyrrole (PPy)/PB core/shell nanoparticles prepared via miniemulsion (periphery) polymerization

We fabricated PPy/PB core/shell nanoparticles via one-step miniemulsion polymerization using a metallosurfactant of EPE-Fe. The defined hollow structure endows PB nanoshells with an emission band at 612 nm. On incorporating PPy inside PB shells, a blue shift and enhanced fluorescence were observed due to charge transfer from PPy to PB.

A facile method to synthesize magnetic polymer nanospheres with multifunctional groups

Magnetic poly(styrene methyl methacrylate)/Fe 3O 4 nanospheres with ester groups were prepared by a modified one-step mini-emulsion polymerization in the presence of Fe 3O 4 ferrofluids. The effects of monomer dose, surfactant content, ferrofluid concentration and initiator content on the particle characteristics such as the size, morphology and magnetic properties were investigated by Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis and vibrating sample magnetometer. The results indicated that magnetic nanospheres were superparamagnetic with high saturation magnetization of 51.0 emu/g and corresponding magnetite content of 61.5 wt%. Subsequently, magnetic nanospheres with carboxyl and amino groups were also obtained by hydrolysis and ammonolysis reaction. These magnetic nanospheres with multifunctional groups have biomedical applications.

Preparation of Fluorescence Tunable Polymer Nanoparticles by One-step Mini-emulsion

Fluorescence tunable polymer nanoparticles were prepared by incorporating two hydrophobic fluorescent dyes (9, 10-diphenylanthracene: DPA and nitrobenzoxadiazolyl: NBD) into polymethylmethacrylate (PMMA) nanoparticles via one-step mini-emulsion polymerization method. The prepared fluorescent nanoparticles exhibit the spectral properties of both DPA and NBD dye, indicating that the two fluorophores have been incorporated into the nanoparticles. The nanoparticles greatly enhance the fluorescence emission of the two hydrophobic dyes in aqueous media probably by providing good protection of the dye molecules in the polymer nanoparticles matrix. Moreover, by varying the doping ratio of the two hydrophobic dyes, the polymer nanoparticles exhibit tunable and distinguishable emission characteristics under a single wavelength excitation via occuring fluorescence resonance energy transfer (FRET).

Controllable preparation of magnetic polymer nanospheres with high saturation magnetization by miniemulsion polymerization

Magnetic Fe 3O 4/poly(styrene-co-acrylamide) core/shell nanospheres were prepared by one-step miniemulsion polymerization in the presence of Fe 3O 4 ferrofluids. The functional monomer of acrylamide was used not only to modify the surface of the nanospheres with functional groups, but also to form modified bilayer with SDBS to control the encapsulation and particle size of nanospheres. The properties of magnetic nanospheres were characterized by IR, TEM, TG and VSM. The results indicated that the superparamagnetic nanopsheres had small particle size of 60 nm, high saturation magnetization of 27.1 emu/g, high magnetic content and abundant functional groups. The possible formation mechanism of magnetic nanospheres was discussed in detail.

Photoreversible Fluorescent Modulation of Nanoparticles via One‐Step Miniemulsion Polymerization

A nitrobenzoxadiazolyl(NBD)-based fluorescent dye and a photochromic spiropyran derivative are incorporated into polymeric nanoparticles via a one-step miniemulsion polymerization. The diameter of the nanoparticles can be varied from approximately 40 nm to 80 nm by adjusting the polymerization conditions. The prepared nanoparticles exhibit the spectral properties of both NBD dye and spiropyran, indicating that the two chromophores are incorporated into the nanoparticles. The determined amount of NBD and spiropyran in the nanoparticles are about approximately 85-90% of the feed amount, while the determined weight ratios of spiropyran to NBD in nanoparticles are very close to that of feed ratios, suggesting the miniemulsion polymerization is a suitable approach for incorporating multiple chromophores into individual nanoparticles with controlled amounts (content) and ratio. UV and visible light can be applied to modulate the fluorescence emission of NBD dye in nanoparticles. Upon UV irradiation, the spiropyran moieties in nanoparticles are converted to the open-ring (McH form) structure and upon visible-light irradiation they return to the closed-ring (SP form) structure; as a result, the fluorescence of NBD can be reversibly "switched off" and "switched on". Fluorescence resonance energy transfer from the excited NBD dye molecules to the McH form of the spiropyran moieties is the drives the fluorescence modulation. The nanoparticles display fairly good photoreversibility, photostability, and relatively fast photoresponsivity upon alternate UV/Vis irradiation. This class of photoresponsive nanoparticles may find applications in biological fields, such as labeling and imaging, as well as in optical fields, for example, individually light-addressable nanoscale devices.

Synthesis and photochromic property of nanoparticles with spiropyran moieties via one-step miniemulsion polymerization

Photochromic nanoparticles with spiropyran moieties were prepared by a facile one-step miniemulsion polymerization. The nanoparticle dispersion was obtained by mixing the monomers, spiropyran-containing molecules and hydrophobe, dispersing them into an aqueous solution with surfactant, subjecting the dispersion to ultrasonification and polymerizing the monomers by using a water soluble initiator. The shape and size of the nanoparticles was determined with the atomic force microscope (AFM) and dynamic light scattering (DLS), and the determined average diameter of the nanoparticles ranges from 30 nm to 60 nm. The absorption and fluorescence spectra for the nanoparticles dispersions reveal that the spiropyran molecules were successfully incorporated in the polymer nanoparticles. Moreover, the nanoparticle dispersions were found to exhibit enhanced photo-reversibility, photo-stability and relatively fast photo-responsive property compare to the same species in aqueous solution.

Synthesis of Asymmetric Inorganic/Polymer Nanocomposite Particles via Localized Substrate Surface Modification and Miniemulsion Polymerization

Asymmetric nanocomposite particle pairs of polystyrene and silica were prepared via one-step miniemulsion polymerization for the first time. The transmission electron microscopy images showed that these nanocomposite particle pairs were monodisperse and highly asymmetric in morphology. The key to obtaining the asymmetric nanocomposite particle pairs was the combination of miniemulsion polymerization and the local surface modification of silica substrates. Because of localized surface modification on the silica surface, the nucleation and formation of the polymer nodule in miniemulsion polymerization took place only in the modified area on the silica surface, thus ensuring the asymmetric morphology. The asymmetrical materials obtained by the facile and effective method will have significant potential applications in some areas including biomedical fields.