Stop flow interference lithography in a microfluidic device

COLL 503

Ji-Hyun Jang, clau@mit.edu1, Dhananjay Dendukuri, dhanu@mit.edu2, Alan Hatton, tahatton@mit.edu2, Edwin L. Thomas, elt@mit.edu1, and Patrick S. Doyle, pdoyle@mit.edu2. (1) Institute for Soldier Nanotechnologies and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, (2) Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
Polymeric structures with repeating 2-Dimensional (2-D) and 3-D motifs on the micron scale and below have many applications. Patterned 2-D structures have been employed in biosensors, tissue engineering and in diagnostic assay systems. We can expect the ability to readily produce sophisticated 3-D structures will offer increased opportunities in these areas. As a subset of interference lithography (IL), phase mask interference lithography (PMIL), has a favorable optics platform since all interfering beams are coming from the same half space. By combining the complementary aspects of PMIL with stop flow lithography that allows for the high throughput synthesis of particles, we have developed Stop Flow Interference Lithography, a new route for the fabrication of 3-D phase mask-defined polymeric particles using liquid, biocompatible, oligomeric precursors in microfluidic channel. A wide range of materials such as stimuli-responsive polymers, biocompatible polymers, polymer-nanoparticle composites etc, can be used as the photopolymerizable liquid to create complex particle shapes at and below the micron scale with this technique. Finally, we show that the high surface area/volume ratio of the structures formed via this technique, may be use to generate high fluorescent signal intensity that could benefit a variety of sensing and diagnostic applications.