Studies on suspension and emulsion. XLVII. Anomalous composite polymer emulsion particles with voids produced by seeded emulsion polymerization

Okubo, Masayoshi; Ando, Motonori; Yamada, Akira; Katsuta, Yoshio; Matsumoto, Takuya

doi:10.1002/pol.1981.130190310

Cited by 100 publications

(35 citation statements)

References 4 publications

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“…This morphology was expected as the emulsion of aqueous droplets in an oil phase relies on surface tension to pull droplets into a spherical shape to minimise surface energy. 36 In this method, droplets are allowed to form completely and relax into a spherical shape before polymerisation. The polymerisation mechanism does not disrupt droplet shape like some extrusion methods used with alginate, 37 and the droplets are completely polymerised within the coil of tubing before they come into contact with each other or come to rest in the collection vessel.…”

Section: Morphologymentioning

confidence: 99%

Poly(vinyl alcohol)-heparin biosynthetic microspheres produced by microfluidics and ultraviolet photopolymerisation

et al. 2013

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Biosynthetic microspheres have the potential to address some of the limitations in cell microencapsulation; however, the generation of biosynthetic hydrogel microspheres has not been investigated or applied to cell encapsulation. Droplet microfluidics has the potential to produce more uniform microspheres under conditions compatible with cell encapsulation. Therefore, the aim of this study was to understand the effect of process parameters on biosynthetic microsphere formation, size, and morphology with a co-flow microfluidic method. Poly(vinyl alcohol) (PVA), a synthetic hydrogel and heparin, a glycosaminoglycan were chosen as the hydrogels for this study. A capillary-based microfluidic droplet generation device was used, and by varying the flow rates of both the polymer and oil phases, the viscosity of the continuous oil phase, and the interfacial surface tension, monodisperse spheres were produced from $200 to 800 lm. The size and morphology were unaffected by the addition of heparin. The modulus of spheres was 397 and 335 kPa for PVA and PVA/heparin, respectively, and this was not different from the bulk gel modulus (312 and 365 for PVA and PVA/heparin, respectively). Mammalian cells encapsulated in the spheres had over 90% viability after 24 h in both PVA and PVA/heparin microspheres. After 28 days, viability was still over 90% for PVA-heparin spheres and was significantly higher than in PVA only spheres. The use of biosynthetic hydrogels with microfluidic and UV polymerisation methods offers an improved approach to long-term cell encapsulation. V C 2013 AIP Publishing LLC. [http://dx

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Section: Morphologymentioning

confidence: 99%

Poly(vinyl alcohol)-heparin biosynthetic microspheres produced by microfluidics and ultraviolet photopolymerisation

et al. 2013

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“…When the second-stage monomer is different from the monomer of the seed polymer, phase separation occurs and many types of heterogeneous morphologies may be formed. Okubo and coworkers [3][4][5][6] showed that heterogeneous composite polymer particles could change the particle morphologies from confetti-like to raspberry-like and containing voids. The film-forming properties of latex depend on the particle morphologies and the surface properties, although the particle morphologies depend on the molecular weights of polymers, the internal particle viscosity during polymerization, polymerization condition, and the difference of the core-shell polymer in hydrophilicity and solubility, for example.…”

Section: Introductionmentioning

confidence: 98%

Particle morphology and NMR structure of polymethylmethacrylate/polystyrene emulsifier‐free core–shell cationic latices in the presence of DBMEA

Zhang

Chai

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:In the absence of emulsifier, we prepared stable emulsifier-free polymethylmethacrylate/polystyrene (PMMA/PSt) copolymer latex by batch method with comonomer N, N-dimethyl, N-butyl, N-methacryloloxylethyl ammonium bromide (DBMEA) by using A1BN as initiator. The size distribution of the latex particles was very narrow and the copolymer particles were spherical and very uniform. Under the same recipe and polymerization conditions, PMMA/PSt and PSt/PMMA composite polymer particle latices were prepared by a semicontinuous emulsifier-free seeded emulsion polymerization method. The sizes and size distributions of composite latex particles were determined both by quasi-elastic light scattering and transmission electron microscopy (TEM). The effects of feeding manner and staining agents on the morphologies of the composite particles were studied. The results were as follows: the latex particles were dyed with pH 2.0 phosphotungestic acid solution and with uranyl acetate solution, respectively, revealing that the morphologies of the composite latex particles were obviously core-shell structures. The core-shell polymer structure of PMMA/PSt was also studied by 1 H, 13 C, 2D NMR, and distortionless enhancement by polarization transfer, or DEPT, spectroscopy. Results showed that PMMA/PSt polymers are composed of PSt homopolymer, PMMA homopolymer, and PMMA-g-PSt graft copolymers; results by NMR are consistent with TEM results.

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“…In the early-stage research, Okubo et al [20][21][22] carried out a series of important experiments to show that the morphology of heterogeneous polymer composite particles could be changed from raspberry-like to snowman-like by seeded emulsion polymerization, depending upon the type and weight ratio of polymers. In 1990, Sheu et al [18,19] reached a milestone in this field.…”

Section: Non-spherical Janus Particlesmentioning

confidence: 99%

Design, Synthesis, and Application of Anisotropic Janus Particles

Zhang¹,

Liang²,

Yang³

2017

Soft, Hard, and Hybrid Janus Structures

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Studies on suspension and emulsion. XLVII. Anomalous composite polymer emulsion particles with voids produced by seeded emulsion polymerization

Cited by 100 publications

References 4 publications

Poly(vinyl alcohol)-heparin biosynthetic microspheres produced by microfluidics and ultraviolet photopolymerisation

Poly(vinyl alcohol)-heparin biosynthetic microspheres produced by microfluidics and ultraviolet photopolymerisation

Particle morphology and NMR structure of polymethylmethacrylate/polystyrene emulsifier‐free core–shell cationic latices in the presence of DBMEA

Design, Synthesis, and Application of Anisotropic Janus Particles

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