MEMS/NEMS and BioMEMS/BioNEMS: Materials, Devices, and Biomimetics

Abstract

Micro-/nanoelectromechanical systems (MEMS/NEMS) micro-/nanoelectromechanical system (MEMS/NEMS) need to be designed to perform expected functions in short durations, typically in the millisecond to picosecond range. The expected life of devices for high-speed contacts can vary from a few hundred thousand to many billions of cycles, e.g., over a hundred billion cycles micromirror device (DMD) digital for digital micromirror devices (DMDs), which puts serious requirements on materials. The surface-area-to-volume ratio in MEMS/NEMS is large, and in systems involving relative motion, surface forces such as adhesion, friction, and meniscus and viscous forces become very large compared with inertial and electromagnetic forces. There is a need for fundamental understanding of adhesion, friction friction/stiction, stiction wear, lubrication, and the role of surface contamination and environment, all on the nanoscale. Most mechanical properties are known to be scale dependent, therefore the properties of nanoscale structures need to be measured. For bioMEMS/bioNEMS, bioMEMS/bioNEMS adhesion between biological molecular layer molecular layers and the substrate, and friction and wear of biological layers, can be important. Component-level studies are required to provide a better understanding of the tribological phenomena occurring in MEMS/NEMS. The emergence of the fields of nanotribology nanotribology and nanomechanics nanomechanics, and atomic force microscopy (AFM) atomic force microscopy (AFM)-based techniques, has provided researchers with a viable approach to address these problems. The emerging field of biomimetics biomimetics holds promise for the development of nanomaterial biologically inspired biologically inspired nanomaterials and nanotechnology products. One example is the design of surfaces with superhydrophobicity roughness-induced roughness-induced superhydrophobicity, self-cleaning, and low adhesion based on the so-called lotus effect. This chapter presents an overview of nanoscale adhesion nanoscale adhesion, friction, and wear wear studies of materials and lubrication lubrication for MEMS/NEMS and bioMEMS/bioNEMS, and component-level studies of stiction phenomena in MEMS/NEMS devices, MEMS/NEMS deviceas well as hierarchical nano-structured surfaces for superhydrophobicity, self-cleaning self-cleaning, and low adhesion.