The objective is to evaluate the processing of SU-8 photosensitive polymers with functionalized, conductive nanoparticles and associated changes in material behavior. Mechanical properties of the composite material can be enhanced by reducing film stresses and creating an ability to grade mechanical properties between two surfaces with large variation in compliance, e.g. silicon and biological tissues. This program will provide initial data on the interaction of SU-8 molecules and nanocrystals and the effects on "bulk" properties for evaluation and refinement of multi-scale material models.
SU-8 is mechanically stable, tough, transparent in UV and visible light spectra, extremely inert chemically, and biocompatible; however, the material shrinkage (7.5%) and film stress (16-19Mpa) upon curing have been barriers to its adoption for the manufacture of polymer microdevices freed from the wafer substrate. Nanocomposites of SU-8 have been demonstrated recently, however the effect of process parameter variation and the resulting material and mechanical properties are unknown. The goals include the evaluation of relationships between uncured characteristics, process parameters, and cured material behavior. This will be accomplished with designed experiments to evaluate the functional relationships. Outcomes will be assessed by microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and mechanical and electrical characterization. Evaluations will include mechanical beam bending and resonance tests to evaluate stiffness and anelasticity.
The intellectual merit of this work includes the development and advancement of nanomanufacturing techniques for the creation of polymer based micro/nano-systems. This program will facilitate the design, fabrication, and characterization of new structures, new materials, and the development of new sensing and actuating solutions without silicon and its extensive accompanying infrastructure. This work will have broad impact in facilitating interdisciplinary research by lowering the traditional barriers of cost, time, and facilities often associated with incorporating microscale and nanoscale devices for assay and manipulation in biological, chemical, and environmental research.
