(421f) Patchy Cluster Formation from Janus PS/P(MMA-GMA) Particles Triggered By Phase Separation Induced By Solvent Swelling/Deswelling

Colloids with anisotropic shapes and directional interaction are promising candidates for the construction of complex materials. One of the main challenges is the synthesis of such objects by precisely controlling the number of functionalities and overall shape. Here we show how nonpolar solvents can induce morphology changes in Janus pear-shaped polystyrene/poly(methyl methacrylate-glycidyl methacrylate) (PS/P(MMA-GMA)) particles. By using chlorinated solvents in particular, protrusions could be formed on the PS lobe upon a swelling-deswelling procedure. We investigated the nature of these protrusions by tuning the composition of the P(MMA-GMA) lobe, from pure PMMA to pure PGMA and various GMA/MMA ratios. We observed how the protrusions size could be varied with increasing GMA content in the lobe and hypothesized how their formation might me related to the presence of PGMA-rich polymers in the P(MMA-GMA) lobe that can phase separate upon solvent deswelling. We took advantage of this feature and produced patchy clusters by purposely destabilizing the swollen particles with NaCl and favor fusion via the PS lobe. We observed how upon deswelling, the clusters formed new protrusions that could be fused into larger patches.

Keywords: Colloidal Aggregation, Controlled Clustering, Janus Particles, Patchy Clusters

References:

[1] G. Russo, M. Lattuada, J. Colloid Interface Sci., 2022, 611, 377-389