Synthesis of Catalytic Microswimmers Based on Anisotropic Platinum Sorption on Melamine Barbiturate Supramolecular Structures

Herein, a straightforward synthesis approach for the formation of anisotropic microswimmers is proposed as an alternative to a top-down fabrication for asymmetric artificial swimmers. Melamine barbiturate (MBA)-self-assembled supramolecular crystals are utilized as an asymmetric matrix for selective chemical platinum deposition. Surface functional groups of prevalent crystallographic planes for platinum sorption are presented by acidic sites of the assembly. The formed platinum catalytic layer is separated from the bulk MBA and investigated using X-Ray photoelectron spectroscopy and scanning electron microscope energy-dispersive X-Ray spectroscopy analysis. Both methods confirm platinum adsorption and reduction of platinum ions during the deposition process. The MBA asymmetric swimmers show directional motion in a fuel environment, proved by the mean-squared displacement study. Previously reported pH-dependency and encapsulation capacity of MBA opens wide opportunities for functional materials formation.

Automated summary

This study proposes a direct synthesis approach for creating anisotropic microswimmers as an alternative to top-down fabrication methods for asymmetric artificial swimmers. Melamine barbiturate (MBA) self-assembled supramolecular crystals are used as an asymmetric matrix for selective chemical platinum deposition. The surface functional groups of the crystals provide acidic sites for platinum sorption, leading to the formation of a platinum catalytic layer. The MBA asymmetric swimmers show directional motion in a fuel environment, and previous studies have shown that MBA has pH-dependency and encapsulation capacity, offering opportunities for the formation of functional materials.