Advanced Fabrication of Mechanical Metamaterials Based on Micro/Nanoscale Technology

In recent years, mechanical metamaterials have shown good mechanical properties such as ultralightness, programmable stiffness, and tunable Poisson's ratio through clever structural design of microstructures. Micro/nanotechnology has been used to ensure mechanical metamaterials' fabrication quality and performance for use as structural substrates in multifunctional applications. Mechanical metamaterials are intentionally engineered with periodic microstructures in diverse shapes, allowing for the creation of complex structural substrates. However, this sophisticated design poses significant challenges in the fabrication process, particularly at the micro/nanoscale level, where current technology hinders mechanical metamaterials' performance improvement and function realization. This review explores the fabrication processes of mechanical metamaterials using micro/nanotechnology and showcase recent progress and future trends. Particular attention is given to recent development, challenges, and future trends in advanced fabrication technologies for mechanical metamaterials. This survey aims to explain why mechanical metamaterials have significant benefits and are well-suited as structural substrates for multifunctional applications, what advanced fabrication technologies at the micro/nanoscale have been introduced to prepare mechanical metamaterials and how to overcome manufacturing technology bottlenecks of mechanical metamaterials in terms of synthesis, materials, and design method.