Soft Patchy Particles of Block Copolymers from Interface-Engineered Emulsions

Abstract

We report a simple and practical method for creating colloidal patchy particles with a variety of three-dimensional shapes via the evaporation-induced assembly of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer (BCP) in an oil-in-water emulsion. Depending on the particle volume, a series of patchy particles in the shapes of snowmen, dumbbells, triangles, tetrahedra, and raspberry can be prepared, which are then precisely tuned by modulating the interfacial interaction at the particle/water interface using a mixture of two different surfactants. Moreover, for a given interfacial interaction, the stretching penalty of the BCPs in the patchy particles can be systematically controlled by adding P4VP homopolymers, which decreases the number of patches of soft particles from multiple patches to a single patch but increases the size of the patch. Calculations based on the strong segregation theory supported the experimental observation of various soft patchy particles and identified the underlying principles of their formation with tunable 3D structures.

Synthesis of Colloidal Molecules: Recent Advances and Perspectives

“…This method is robust without the requisites of narrow molecular weight distribution and a specific range of block fraction of the copolymers. Later, the strategy was extended for the synthesis of PS nanoparticles with up to nine P4VP protrusions (AX 9 ‐type CMs) by increasing the volume of the emulsion droplet, that is, the volume of the particle (Figure a) . For a given particle volume, the morphology can also be precisely tuned by modulating the interfacial interaction at the particle/water interface using a mixture of two different surfactants …”

“… a) PS‐ b ‐P4VP CMs fabricated through oil‐in‐water emulsion (scale bars: 100 nm) . Representative TEM images of b) Ag‐Pt‐Fe 3 O 4 and c) PMMA/silica/PS heterotrimers mimicking AXY‐type CMs.…”

“…[24,25] For ag iven particlev olume, the morphologycan also be precisely tuned by modulating the interfacial interaction at the particle/wateri nterface using am ixture of two different surfactants. [25]…”

“…a) PS-b-P4VP CMs fabricated through oil-in-water emulsion (scale bars:100 nm). [25] Representative TEM images of b) Ag-Pt-Fe 3 O 4 [29] and c) PMMA/ silica/PS [32] heterotrimers mimicking AXY-typeC Ms. d) CMso fdiamagnetic particles with X 5 ,X 4 ,X 6 and X 7 geometries (scale bars:2mm). [34] e) AXY-like CMs assembled by sequentialc apillarity-assisted assembly (scale bars:5mm).…”

“…[43] Adaptedw ith permission from Refs. [25], [29], [ 32], [ 34],and [43],c opyrightA CS 2015, NPG 2012, RSC 2012, NPG 2013 and ACS 2015. namely 2,2'-azobis(N,N'-dimethylene isobutyramidine) dihydrochloride. We observed the formationo fl inear AXY-type CMs where the PMMA latex standso nt he initially free silica hemisphere in mainly linear arrangements ( Figure 2c).…”