A facile fabrication of amphiphilic Janus and hollow latex particles by controlling multistage emulsion polymerization.

In this paper, we found that morphology controllable compound latex particles could be prepared by controlling the multistage emulsion polymerization. Influences of the content of methacrylic acid (MAA) on preparing the hydrophilic cores and the particles were investigated with the observation of dynamic light scattering (DLS) and transmission electron microscope (TEM) results. The acorn-like latex particles were synthesized by partially encapsulated with hydrophobic polystyrene (PSt)-layer. With adding moderate polarity polymethylmethacrylate (PMMA) interlayer, the hydrophilic cores could be fully encapsulated by the hydrophobic PSt-layer, and the core-shell structure formed. After alkali treatment, the acorn-like and core-shell latex particles evolved into amphiphilic Janus and hollow latex particles, respectively. The morphology of latex particles was investigated by TEM, and the forming mechanism of amphiphilic Janus and hollow latex particles was proposed.
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