One-Step Synthesis of Quadrilateral-Shaped Silver Nanoplates with Lamellar Structures Tuned by Amylopectin Derivatives

Polymers or small molecules with functional groups were always employed to synthesize two-dimensional (2D) silver nanostructures, but the polysaccharides and derivatives have rarely been used for their preparation, let alone of uniform quadrilateral shapes. Herein, amylopectin derivatives containing concentrated carboxyl groups were first used for the synthesis of uniform 2D quadrilateral silver nanoplates (QAgNPs) with lamellar structure. As a native hyperbranched polysaccharide, amylopectin was esterified with 10-undecenoyl chloride and then modified via thiol-ene click chemistry to introduce high amount and high density of carboxyl groups. Then, QAgNPs were synthesized via UV photoreduction in the presence of the resultant amylopectin 11-((3-carboxyl)ethylthio)undecanoate (APUE₃-MPA) in water-tetrahydrofuran binary system. QAgNPs showed novel uniform quadrilateral shapes with lamellar structure, as verified by their wide-angle X-ray scattering patterns. The average interlayer distance was around 1.3 nm, whereas the average edge lengths of QAgNPs varied between 0.29 ± 0.07 and 1.09 ± 0.25 μm. The concentration of APUE₃-MPA and the amount of water in the reaction system strongly affected the shapes of QAgNPs. Thus, the reaction system and the arrangement of numerous carboxyl groups were the key factors for the formation of lamellar-structured QAgNPs.