Formation of “Snowmanlike” Polystyrene/Poly(methyl methacrylate)/Toluene Droplets Dispersed in an Aqueous Solution of a Nonionic Surfactant at Thermodynamic Equilibrium

Saito, Naohiko; Nakatsuru, Reiko; Kagari, Yoshimi; Okubo, Masayoshi

doi:10.1021/la701388w

Cited by 64 publications

(57 citation statements)

References 48 publications

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“…Previous work 37 has shown that a non-ionic surfactant (polyoxyethylene nonylphenylether with an average ethylene oxide Preparation of hemispherical polystyrene particles T Tanaka et al chain length of 10.9) dissolved into both the oil and aqueous phases and significantly reduced the oil-aqueous medium interfacial tension. Figure 4 shows the variation of Emulgen concentrations in aqueous media as a function of the toluene weight fraction relative to the total amount of toluene, water and Emulgen.…”

Section: Resultsmentioning

confidence: 99%

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Preparation of hemispherical polystyrene particles utilizing the solvent evaporation method in aqueous dispersed systems

Tanaka

Yamagami

Nogami

et al. 2012

Polym J

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Various nonspherical polystyrene (PS) particles were prepared by slow evaporation of toluene (used common good solvent) from homogeneous PS/hexadecane (HD)/toluene droplets dispersed in surfactant aqueous solutions at room temperature, followed by the rapid removal of HD from PS/HD particles with various phase-separated morphologies. The morphology of PS/HD particles was controlled by tuning the interfacial tension with various types of surfactants. Hemispherical PS particles with flat surfaces were obtained from phase-separated PS/HD/toluene droplets having a Janus structure, when polyoxyethylene nonylphenyl ether with an average ethylene oxide chain length of 30.8 was used as the surfactant. Polymer Journal ( Keywords: nonspherical particles; hemisphere; solvent evaporation method; phase separation; interfacial tension; polystyrene INTRODUCTION Nonspherical polymer particles have attracted great attention because of their potential as materials with unique crystal structures, 1-3 light scattering properties 4 and external field-responsive properties (e.g., shear field 5 and electric field 6 ). In general, polymer particles synthesized by heterogeneous polymerizations under thermodynamic control have a spherical shape because of interfacial free energy minimization. However, nonspherical polymer particles have been synthesized under kinetic control utilizing various seeded polymerization methods, 7-24 microfluidic techniques, 25-28 deformation of spherical polymer particles by external force, 29-31 the stepwise heterocoagulation method 32,33 and the self-organized precipitation method. 34 In a previous work, we proposed a novel approach for the preparation of micrometer-sized, monodisperse, nonspherical (i.e., dimpled and hemispherical) polystyrene (PS) particles by successive heating and cooling of spherical PS particles dispersed in a methanol/ water medium in the presence of droplets of decane. 35 Decane was absorbed by the particles during heating, and the particles subsequently phase-separated into PS and decane phases during cooling. Eventually, nonspherical particles reflecting the morphology of phase-separated PS/decane particles were formed by rapid removal of the decane phase. The final particle shape could be controlled simply with the amount of absorbed decane.We have also recently demonstrated morphology control of PS/poly(methyl methacrylate) composite particles prepared by the slow release of toluene as a common good solvent from homogeneous PS/poly(methyl methacrylate)/toluene droplets dispersed in a surfactant aqueous solution at room temperature (the solvent evaporation method). [36][37][38] It was revealed that the particle morphology could be

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Section: Resultsmentioning

confidence: 99%

“…[36][37][38] It was revealed that the particle morphology could be controlled by tuning the interfacial tensions by varying the types of surfactant.…”

Section: Introductionmentioning

confidence: 99%

Preparation of hemispherical polystyrene particles utilizing the solvent evaporation method in aqueous dispersed systems

Tanaka

Yamagami

Nogami

et al. 2012

Polym J

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“…2A). This indicated that, despite the carboxylic charge derived from the V501 on the surface, Table 2 Ab-initio emulsion polymerizations of styrene or (butyl acrylate-co-methyl methacrylate) using Janus polystyrene nanoparticles which have V-501 derived cross-linked polystyrene seeds stabilized by RAFT-Sty 20 Scheme 3 Schematic behaviour of the monomer swollen cross-linked polymer seed on heating. The wetting ability of the monomer governs the morphology of the anisotropic particles formed during subsequent polymerization.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of polymeric janus nanoparticles and their application in surfactant-free emulsion polymerizations

Pham

Such²,

Hawkett

2015

Polym. Chem.

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A robust and simple synthesis of nano-size oblate to dumbbell shaped polymeric anisotropic particles using RAFT mediated emulsion polymerization is presented. The particle synthesis relies on the property that monomer swollen cross-linked polymer seed particles shrink and expel some of the monomer when heated. Thus, upon heating for polymerization, some of the swelling monomer is expelled and subsequently polymerizes to form a bulge on the side of the original crosslinked seed particle. The shape of the bulge, and the degree of contact that the expelled monomer maintains with the original seed particle, is controlled by controlling the wettability of the seed surface by the expelled monomer. Very small monodisperse cross-linked polymer particles are initially prepared by RAFT mediated emulsion polymerization, then swollen with monomer and further polymerized to form anisotropic particles with a long dimension as little as 25 nm. Both the shape of the anisotropic bulge and the polymer composition, of each end of the final Janus nanoparticle can be finely controlled. The surface active properties of the Janus nanoparticles are demonstrated by their ability to contribute as stabilizers and influence particle formation in a surfactant free ab-initio emulsion polymerization. The method provides a simple and reproducible process for the production of Janus colloidal nanoparticles readily achievable in a normal latex plant where batch size would be limited only by the size of the reactor.

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“…Therefore, the fragmented nanosheets would be included in innovative anisotropic nanomaterials as proposed previously, e.g., inorganic nanosheets composed of graphene dissociated from graphite [30,31] and anisotropic polymer particles (discs- and snowman-like shapes, etc. ) fabricated by seeded dispersion polymerization [32,33]. …”

Section: Fabrication and Characterization Of Submillimeter-sized Nmentioning

confidence: 99%

Patchwork Coating of Fragmented Ultra-Thin Films and Their Biomedical Applications in Burn Therapy and Antithrombotic Coating

Okamura

Takeoka

2015

Materials

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We have proposed free-standing centimeter-sized ultra-thin films (nanosheets) for biomedical applications. Such nanosheets exhibit unique properties such as transparency, flexibility, and good adhesiveness. However, they are only easily adhered to broad and flat surfaces due to their dimensions. To this end, we recently proposed an innovative nanomaterial: the nanosheets fragmented into submillimeter-size pieces. Intriguingly, such fragmented nanosheets could be adhered to uneven and irregular surfaces in addition to flat surfaces in a spread-out “patchwork” manner. We herein review the fabrication procedure and characterization of fragmented nanosheets composed of biodegradable polyesters and thermostable bio-friendly polymers, and their biomedical applications in burn therapy and antithrombotic coating using a “patchwork coating”.

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Formation of “Snowmanlike” Polystyrene/Poly(methyl methacrylate)/Toluene Droplets Dispersed in an Aqueous Solution of a Nonionic Surfactant at Thermodynamic Equilibrium

Cited by 64 publications

References 48 publications

Preparation of hemispherical polystyrene particles utilizing the solvent evaporation method in aqueous dispersed systems

Preparation of hemispherical polystyrene particles utilizing the solvent evaporation method in aqueous dispersed systems

Synthesis of polymeric janus nanoparticles and their application in surfactant-free emulsion polymerizations

Patchwork Coating of Fragmented Ultra-Thin Films and Their Biomedical Applications in Burn Therapy and Antithrombotic Coating

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