Large arrays of MEMS with programmable electrodes and electromagnets are used to achieve microscale positioning of particles, whiskers, and fibers in polymer matrix materials. Arrays of MEMS are placed above and beneath thin layers of a random particle-filled liquid polymer. Microscale variations in the electric and magnetic fields are then used to control body forces that move the piezoelectric and piezomagnetic particles. The body forces are due to the gradients in the E and B fields. Such body forces are generally small on a macroscopic scale. However, standard microfabrication methods enable the generation of very high gradients in E and B on the microscale, therefore generating body forces large enough to overcome microscopic sedimentation forces, viscous forces, and the mutual attraction of particles. We discuss the free body diagram of a particle, the design of MEMS arrays using a finite element code (ANSYS) to determine the electric and magnetic fields, and the fabrication of the MEMS arrays. Currently there is no way to affordably arrange the particles in the optimal microscale pattern in composite materials. Ideally, the current method will provide an affordable and versatile method of patterning the microstructure of multi-functional composite materials, sensors, actuators.

Date Published: 22 July 2003
PDF: 10 pages
Proc. SPIE 5055, Smart Structures and Materials 2003: Smart Electronics, MEMS, BioMEMS, and Nanotechnology, (22 July 2003); doi: 10.1117/12.483590

Published in SPIE Proceedings Vol. 5055:
Smart Structures and Materials 2003: Smart Electronics, MEMS, BioMEMS, and Nanotechnology
Vijay K. Varadan; Laszlo B. Kish, Editor(s)