Mechanophysical Synthesis of Core/Shell Hybrid Supraparticles

Abstract

Surface modification of polymer microparticles (MPs) is often essential to impart functionalities beyond their inherent properties. However, decorating these surfaces typically requires complex, multi-step wet chemistry processes to direct assembly and bonding between surfaces, which are not only challenging to control and scale up but also pose significant environmental concerns. Inspired by asteroid impact events, assembly of core/shell hybrid supraparticles (HSPs) is demonstrated via collision-driven, one-step dry mixing of inorganic nanoparticles (NPs) and polymer MPs with a significant contrast in elastic moduli- a process termed "mechanophysical synthesis." Through the interplay of interfacial energy and collision energy, NPs are stably embedded onto the MP surface. The degree of surface coverage depends on mixing velocity and duration, aligning with results from particle collision simulations. HSPs can be created from a diverse combination of MPs and NPs, regardless of their shapes or chemistry. Furthermore, different types of functional NPs-such as magnetic, photocatalytic, and ion-adsorptive-can be simultaneously introduced onto the MPs. The resulting HSPs can not only remove toxic water pollutants, but also be easily recovered and reused. The mechanophysical synthesis approach opens a new direction for sustainable and versatile self-assembly of heterogeneous MPs, minimizing the use of excessive chemicals and solvents.