Intrinsically Magnetic High-Entropy Alloy Nanoparticles for Self-Assembly into Hierarchical Structures

Ohio State University, The, Columbus OH

Investigators

Abstract

Controlling how tiny particles come together is essential for creating new materials used in various technologies such as medical imaging and flexible electronics. However, controlling particles that are nanometers in size is still very challenging using available techniques. This project will develop new methods to guide these particles into organized structures by using an alloy mixture of five or more metals. By using their natural magnetism, this project aims to make the particles line up into chains, loops, and eventually larger networks. This award will push the boundaries of materials science and engineering and will support future innovations in areas like high-density data storage, soft robotics, and environmental monitoring. It will also provide training for students at multiple levels as well as outreach to K–12 students through hands-on workshops and science education modules. This project will use the magnetic self-assembly of high-entropy alloy (HEA) nanoparticles as a platform for directing the formation of hierarchical nanostructures. Traditional strategies for nanoparticle assembly are ineffective in the nanometer regime due to weak depletion forces and insufficient directional interactions. This project will use multicomponent HEA nanoparticles that can retain stable dipolar magnetic domains at these scales, overcoming the superparamagnetic limit common in conventional nanomagnets. The project is structured around three integrated thrusts: (1) synthesis of HEA nanoparticles with intrinsic magnetic properties; (2) directed assembly of these nanoparticles into chains and loops through intrinsic magnetic interactions; and (3) alignment of these structures into higher-order architectures using external fields. Experimental techniques such as electron holography, electron microscopy, and magnetic force mapping will be combined with theoretical modeling of interparticle interactions to understand and control the assembly mechanisms. Outcomes are expected to help in developing scalable routes to synthesize nanoparticles with customized properties and advance knowledge in nanomagnetism and colloidal self-assembly. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.