A miniature flow sensor fabricated by micro-stereolithography employing a magnetite/acrylic nanocomposite resin

Micro-stereolithography (MSL) is an important technique for fabrication of three-dimensional (3D) structures and micro-devices. With the recent developments to the MSL process such as the use of multiple resins in single components, the number of applications for devices produced with this process has expanded greatly. MSL technology is also opening up new paradigms in the area of microelectromechanical systems (MEMS) research and applications, with fabrication of custom, precise and low-cost devices a reality. MSL resins that provide functionality beyond the purely structural are required to meet the ever increasing demand for more complex sensors and devices that can be used in custom applications. Functionality can be introduced into MSL polymer resins through addition of particulate fillers into the resin matrix. Here, magnetite (Fe3O4) nanoparticles (approx 50 nm diameter) were introduced into a resin matrix and used for the fabrication of a flow sensor device. The rotation of the impeller can be determined using an external magnetic field sensor not in contact with the device. The speed of the impeller is examined to find the range over which a proportional increase in the speed with applied pressure is achieved. Such sensors could prove useful due to their rapid, low cost and custom fabrication, where the structure of the sensor can be altered/refined as required while the electronic components are retained for further use. (C) 2011 Elsevier B.V. All rights reserved.