A directional chemical or physical interaction between microcolloids can be realized through pre-defined sites on their surface, “patches”, which might make them follow each other in a controlled way and assemble into target structures of more complexity. In our work, we put our main effort on the fabrication and study of the self-assembly behavior of mono-patchy melamine formaldehyde (MF) microparticles with oppositely charged patches made of poly (methyl vinyl ether-alt-maleic acid) (PMVEMA) or polyethyleneimine (PEI), respectively. Microcontact printing (μCP) as a mild and quick method was used for the successful deposition of the polyelectrolyte ink onto the surface of the MF microparticles (Fig. 1). The effects of the concentration as well as the molecular weight M<sub>w</sub> of the polymeric ink on the yield and the thickness of the resulting patches were studied. Furthermore, the aggregation behavior of the mono-patchy MF particles was investigated as a function of pH for each type of patches separately. Some possible types of particulate dimers were formed via patch-patch, particle-particle, and patch-particle interactions. A statistical analysis of the formed dimers via patch-particle interactions demonstrated a maximum at specific pH. This value is in a good agreement with our calculations based on a simplified model of the Coulomb`s law for the electrostatic force between localized charges for both types of patchy particles with patches made of PMVEMA or PEI (Fig. 2).

Zwitterionic patchy polymer microparticles for a controlled self-assembly

2019 Spring National Meeting

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