Nanomechanical characterization of polymer beam structures for BioMEMS applications

Polymer microstructures are incorporated in biomicroelectromechanical system (BioMEMS) devices with applications ranging from drug creening to defense applications. Nanomechanical characterization of the polymer components must be carried out in order to design reliable evices. This paper presents the nanoindentation characterization of polymer beams fabricated through soft lithography-based techniques for ioMEMS applications. Poly(propyl methacrylate) (PPMA), poly(methyl methacrylate) (PMMA), polystyrene (PS) and a nanocomposite of olystyrene and clay (PS/Clay) were investigated in this study. The hardness, elastic modulus and creep behavior of microbeams made from these aterials were measured using continuous stiffness measurement (CSM) nanoindentation, and the scratch resistance of thin films was measured sing a nanoscratch technique. Yield and breaking strengths were determined by normal beam bending at elevated loads, in which the presence f the nanoclay filler in the composite modified the deformation behavior relative to the unfilled polystyrene. Lateral bending of PS and PS/Clay antilever beams is demonstrated for the first time. The mechanical response of beams after soaking in deionized water or heating to human body emperature was examined. 2006 Elsevier B.V. All rights reserved.