Ku, Kang Hee Lee, Young Jun Yi, Gi-Ra Jang, Se Gyu Schmidt, Bernhard V. K. J. Liao, Kin Klinger, Daniel Hawker, Craig J. Kim, Bumjoon J. 2024-01-20T00:00:44Z 2024-01-20T00:00:44Z 2021-09-03 2017-12-12 0024-9297 https://pubs.kist.re.kr/handle/201004/121925 We report a simple and robust strategy to prepare pH responsive biphasic Janus particles composed of polystyrene/poly(2-vinylpyridine) (PS/P2VP) homopolymers that are able to control, the reversible formation, breakage, and switching of Pickering emulsions depending on their geometry- and pH-dependent hydrophilic-lipophilic balance. The chemical stability of these PS/P2VP Janus particles was tuned through the incorporation of cross-linkable benzophenone units along the backbone of the homopolymers. By employing these stabilized particles as emulsifiers for toluene and water, a facile transformation of emulsion types (i.e., from toluene-in-water to water-in-toluene emulsions) was achieved by adjusting the pH of the aqueous phase. More importantly, this pH-dependent switching behavior and associated stability of the emulsions could be actively controlled by adjusting the relative size ratio of PS to P2VP. When the PS volume fraction (phi(PS)) was between 0.33 and 0.67, a wide range tuning of emulsionphase including rapid and reversible pH-triggered emulsion inversion was achieved by the Janus surfactants. Finally, incorporation of iron oxide nanoparticles facilitated magnetic separation of oil droplets from O/W emulsions and recovery of the Janus particles, which represents a considerable advantage for these systems. English AMER CHEMICAL SOC PICKERING EMULSIONS GOLD NANOPARTICLES DIBLOCK COPOLYMERS THIN-FILMS PS-B-P4VP(PDP) SUPRAMOLECULES COMPOSITE-PARTICLES COLLOID SURFACTANTS BLOCK-COPOLYMERS PHASE-TRANSITION FLUID INTERFACES Shape-Tunable Biphasic Janus Particles as pH-Responsive Switchable Surfactants Article 10.1021/acs.macromol.7b02365 1 MACROMOLECULES, v.50, no.23, pp.9276 - 9285 MACROMOLECULES 50 23 9276 9285 scie scopus 000418206800020 2-s2.0-85038215007 Polymer Science Polymer Science Article PICKERING EMULSIONS GOLD NANOPARTICLES DIBLOCK COPOLYMERS THIN-FILMS PS-B-P4VP(PDP) SUPRAMOLECULES COMPOSITE-PARTICLES COLLOID SURFACTANTS BLOCK-COPOLYMERS PHASE-TRANSITION FLUID INTERFACES block copolymer nanoparticle surfactant janus drug delivery