Processing–Structure–Property–Performance relationships of polymer composites for untethered magnetic robotics

Abstract

Miniaturized magnetic robots can be wirelessly maneuvered into hard-to-reach regions beyond the limits of manual control, enabling diverse functionalities such as drug delivery, microfluidic control, cargo transportation, ultraprecision polishing, and microplastic removal. From the perspective of mechanical engineering, robot locomotion has been extensively discussed in previous reviews. However, targeted and high-precision actuation requires multidisciplinary understanding from the perspective of polymer and materials science, which remains insufficiently covered in earlier reviews. This review aims to elucidate processing–structure–property–performance relationships in recent magnetically responsive polymer composites (i.e., magnetic polymer composites) for magnetic robot actuation. We address processing strategies and underlying rationales for magnetic polymer composites by considering magnetic properties of magnetic fillers and thermal processability of polymer matrices. Locomotion of millimeter-to-nanometer scale robots is discussed based on comprehensive understanding of processing, structure, properties, and actuation of magnetic polymer composites. This review offers insights required to advance magnetic robotics, paving the way for future miniaturized actuators and robots with diverse biomedical, environmental, industrial, and interdisciplinary functions.