1 Materials and methods for microfabrication of microfluidic devices

Microfabrication for microfluidic applications uses a wide variety of materials and methods that range from conventional microfabrication techniques such as photolithography to mass fabrication techniques such as injection molding. This chapter provides an overview of the various techniques used by broadly classifying them as photolithographic, replication-based, and xurographic microfabrication. Replication-based microfabrication is broken down further into soft lithographic, hot embossing, and injection molding to provide examples of prototyping and mass fabrication that are used. The chapter then looks at the wide variety of materials used in microfluidic microfabrication, classified broadly into glass, silicon, polymers, paper, thread, and pressure sensitive adhesives. The conventional fabrication methods used with each material, a few applications that use the characteristics of the material, and the challenges associated with it are presented to provide a glimpse of the numerous choices of materials available in microfabrication. In the conclusion, a short summary of the current state of material use and reasons for widespread adoption of polymeric materials is presented.