Division of Applied Chemistry, Graduate School of Engineering , Osaka Institute of Technology , 5-16-1 Omiya , Asahi-ku, Osaka 535-8585 , Japan.
Priority Research Centre for Advanced Particle Processing and Transport , University of Newcastle , Callaghan , New South Wales 2308 , Australia.
Langmuir. 2018 May 1;34(17):4970-4979. doi: 10.1021/acs.langmuir.7b04204. Epub 2018 Apr 16.
Aqueous dispersions of micrometer-sized, monodisperse polystyrene (PS) particles carrying pH-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) colloidal stabilizer on their surfaces were dried under ambient conditions at pH 3.0 and 10.0. The resulting dried cake-like particulate materials were ground into powders and used as a stabilizer to fabricate liquid marbles (LMs) by rolling and electrostatic methods. The powder obtained from pH 3.0 aqueous dispersion consisted of polydisperse irregular-shaped colloidal crystal grains of densely packed colloids which had hydrophilic character. On the other hand, the powder obtained from pH 10.0 aqueous dispersion consisted of amorphous and disordered colloidal aggregate grains with random sizes and shapes, which had hydrophobic character. Reflecting the hydrophilic-hydrophobic balance of the dried PDEA-PS particle powders, stable LMs were fabricated with distilled water droplets by rolling on the powders prepared from pH 10.0, but the water droplets were adsorbed into the powders prepared from pH 3.0. In the electrostatic method, where an electric field assists transport of powders to a droplet surface, the PDEA-PS powders prepared from pH 3.0 jumped to an earthed pendant distilled water droplet to form a droplet of aqueous dispersion. Conversely the larger powder aggregates prepared from pH 10.0 did not jump due to cohesion between the hydrophobic PDEA chains on the PS particles, resulting in no LM formation.
在 pH 值为 3.0 和 10.0 的环境条件下，将表面带有 pH 响应性聚[2-(二乙基氨基)乙基甲基丙烯酸酯]（PDEA）胶体稳定剂的微米级单分散聚苯乙烯（PS）颗粒的水基分散体进行干燥。将得到的干燥的蛋糕状颗粒材料研磨成粉末，并用作稳定剂，通过滚动和静电方法制备液滴（LM）。从 pH 值为 3.0 的水基分散体获得的粉末由具有亲水性的紧密堆积胶体的多分散不规则形状胶体晶体颗粒组成。另一方面，从 pH 值为 10.0 的水基分散体获得的粉末由具有无定形和无序胶体聚集颗粒组成，其具有疏水性且颗粒尺寸和形状随机。反映干燥 PDEA-PS 颗粒粉末的亲水-疏水平衡，通过在 pH 值为 10.0 制备的粉末上滚动来制备稳定的 LM，但是水滴滴入 pH 值为 3.0 的粉末中。在静电方法中，电场有助于粉末向液滴表面的传输，从 pH 值为 3.0 制备的 PDEA-PS 粉末会跳至接地的悬挂式蒸馏水液滴上，形成分散在水中的液滴。相反，由于 PS 颗粒上的疏水性 PDEA 链之间的内聚力，从 pH 值为 10.0 制备的较大粉末聚集体不会跳跃，从而导致没有 LM 形成。
