3 research outputs found

    Microcapsules Fabricated from Liquid Marbles Stabilized with Latex Particles

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    Millimeter- and centimeter-sized “liquid marbles” were readily prepared by rolling water droplets on a powder bed of dried submicrometer-sized polystyrene latex particles carrying poly­[2-(diethylamino)­ethyl methacrylate] hairs (PDEA-PS). Scanning electron microscopy studies indicated that flocs of the PDEA-PS particles were adsorbed at the surface of these water droplets, leading to stable spherical liquid marbles. The liquid marbles were deformed as a result of water evaporation to adopt a deflated spherical geometry, and the rate of water evaporation decreased with increasing atmospheric relative humidity. Conversely, liquid marbles formed using saturated aqueous LiCl solution led to atmospheric water absorption by the liquid marbles and a consequent mass increase. The liquid marbles can be transformed into polymeric capsules containing water by exposure to solvent vapor: the PDEA-PS particles were plasticized with the solvent vapor to form a polymer film at the air–water interface of the liquid marbles. The polymeric capsules with aqueous volumes of 250 μL or less kept their oblate ellipsoid/near spherical shape even after complete water evaporation, which confirmed that a rigid polymeric capsule was successfully formed. Both the rate of water evaporation from the pure water liquid marbles and the rate of water adsorption into the aqueous LiCl liquid marbles were reduced with an increase of solvent vapor treatment time. This suggests that the number and size of pores within the polymer particles/flocs on the liquid marble surface decreased due to film formation during exposure to organic solvent vapor. In addition, organic–inorganic composite capsules and colloidal crystal capsules were fabricated from liquid marbles containing aqueous SiO<sub>2</sub> dispersions

    Microcapsules Fabricated from Liquid Marbles Stabilized with Latex Particles

    No full text
    Millimeter- and centimeter-sized “liquid marbles” were readily prepared by rolling water droplets on a powder bed of dried submicrometer-sized polystyrene latex particles carrying poly­[2-(diethylamino)­ethyl methacrylate] hairs (PDEA-PS). Scanning electron microscopy studies indicated that flocs of the PDEA-PS particles were adsorbed at the surface of these water droplets, leading to stable spherical liquid marbles. The liquid marbles were deformed as a result of water evaporation to adopt a deflated spherical geometry, and the rate of water evaporation decreased with increasing atmospheric relative humidity. Conversely, liquid marbles formed using saturated aqueous LiCl solution led to atmospheric water absorption by the liquid marbles and a consequent mass increase. The liquid marbles can be transformed into polymeric capsules containing water by exposure to solvent vapor: the PDEA-PS particles were plasticized with the solvent vapor to form a polymer film at the air–water interface of the liquid marbles. The polymeric capsules with aqueous volumes of 250 μL or less kept their oblate ellipsoid/near spherical shape even after complete water evaporation, which confirmed that a rigid polymeric capsule was successfully formed. Both the rate of water evaporation from the pure water liquid marbles and the rate of water adsorption into the aqueous LiCl liquid marbles were reduced with an increase of solvent vapor treatment time. This suggests that the number and size of pores within the polymer particles/flocs on the liquid marble surface decreased due to film formation during exposure to organic solvent vapor. In addition, organic–inorganic composite capsules and colloidal crystal capsules were fabricated from liquid marbles containing aqueous SiO<sub>2</sub> dispersions

    pH-Responsive Hairy Particles Synthesized by Dispersion Polymerization with a Macroinitiator as an Inistab and Their Use as a Gas-Sensitive Liquid Marble Stabilizer

    No full text
    We studied dispersion polymerization in detail using <i>well-defined</i> pH-responsive poly­[2-(diethylamino)­ethyl methacrylate]- (PDEA-) based macroinitiators as an inistab (<i>ini</i>tiator + <i>stab</i>ilizer). Colloidally stable polystyrene (PS) latex particles carrying pH-responsive PDEA hair (PDEA–PS particles) were successfully synthesized in polymerization media with solubility parameters ranging between 22.3 (MPa)<sup>1/2</sup> and 26.0 (MPa)<sup>1/2</sup>. The number-average particle diameters were finely controlled between 90 and 460 nm. The PDEA–PS latex particles were dispersed in acidic aqueous media in which the PDEA hair was protonated and solvated, and were flocculated in basic aqueous media in which the PDEA hair was deprotonated and precipitated. The dried PDEA–PS particles served as an effective gas-responsive stabilizer for liquid marbles. The liquid marbles were stable in H<sub>2</sub>O vapor for over 18 h, but disintegrated immediately (<2 s) upon exposure to HCl gas
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