Size‐Controlled Formation of Polymer Janus Discs

Abstract

A straightforward method is presented for the preparation of nano‐ to micrometer‐sized Janus discs with controlled shape, size, and aspect ratio. The method relies on cross‐linkable ABC triblock terpolymers and involves first the preparation of prolate ellipsoidal microparticles by combining Shirasu porous glass (SPG) membrane emulsification with evaporation‐induced confinement assembly (EICA). By varying the pore diameter of the SPG membrane, we produce Janus discs with controlled size distributions centered around hundreds of nanometers to several microns. We further transferred the discs to water by mild sulfonation of PS to polystyrene sulfonic acid (PSS) and verified the Janus character by subsequent labelling with cationic nanoparticles. Finally, we show that the sulfonated Janus discs are amphiphilic and can be used as efficient colloidal stabilizers for oil‐in‐water (O/W) emulsions.

Janus Nanoshards Prepared Based on High Internal Phase Emulsion Templates for Compatibilizing Immiscible Polymer Blends

“…34 Additionally, the single-sided adsorption of gold nanoparticles has been adopted to confirm the asymmetrical chemical structure of the Janus particles successfully. 35 In this paper, the chemical asymmetry of PS−silica−amine nanoshards was verified by the adsorption of citrate-stabilized gold nanoparticles. It is clearly observed in Figure 3 that the surface with irregular nodules (PS chain-modified side) is free of gold nanoparticles, while the nodule-free surface (amino-modified side) of the PS− silica−amine nanoshards is covered by gold nanoparticles densely.…”

“…The asymmetry of the Janus particles can be visualized through comparing the phase shift of the two sides and identifying the difference in the adhesion between the tip and sample surface with atomic force microscopy . Additionally, the single-sided adsorption of gold nanoparticles has been adopted to confirm the asymmetrical chemical structure of the Janus particles successfully . In this paper, the chemical asymmetry of PS–silica–amine nanoshards was verified by the adsorption of citrate-stabilized gold nanoparticles.…”

Polymer-Derived Janus Particles at Multiple Length Scales

“…More uniform pupa-like spheres were attained by Shirasu porous glass membrane emulsification. 45 A well-defined Janus nanocup with different constituents compartmentalized inside and outside the wall was constructed, and the mechanical properties could be directly controlled with the length of the cross-linkable groups. 46 Other morphologies, including Janus nanorings, were generated by selective cross-linking the exterior edge of PB lamella at the PSb-PB-b-PMMA pupa-like sphere with OsO 4 .…”

“…After selective cross-linking the two layers of P4VP, Janus discs of PS–P4VP were derived via disassembly. More uniform pupa-like spheres were attained by Shirasu porous glass membrane emulsification . A well-defined Janus nanocup with different constituents compartmentalized inside and outside the wall was constructed, and the mechanical properties could be directly controlled with the length of the cross-linkable groups .…”

Shaping Block Copolymer Microparticles by Positively Charged Polymeric Nanoparticles

“…[16][17][18][19][20][21][22] In addition to amphiphilic molecules, nanoparticles (NPs) can also be used as surfactants to regulate the interfacial interactions and thus the 3D confined assembly of BCPs. For example, inorganic NPs, such as CuPt nanorods, [23] gold NPs, [24] graphene quantum dots, [25] and others, [26,27] have been used to shape BCP microparticles into different structures, including footballlike, [28] onion-like, [29,30] Janus pupa-like particles, [26] and others. [31,32] Particularly, the introduction of charged NPs at the oilwater interface could tune the electrostatic interactions, which could change the interfacial tension, interfacial selectivity, as well as the morphology of BCP microparticle.…”