Producing, characterization and applications of 3D polymer fibers.
Goal: Fabricate 3D polymer micro/nano fibers and develop fiber networks using these fibers. Characterize the fibers to find the mechanical and morphological behaviors. Use these fibers as high performance filters, protective textiles, advanced composites, photovoltaic cells, scaffolds in tissue engineering, actuators and sensors, thermal and sound insulators etc.
Approach: Polymer fibers are produced using two techniques. One of them produces single micro/nano fibers using probe based drawing with a sharp needle. In this process, the needle is dipped and retracted from a droplet of polymer solution or polymer solution is forced to flow inside the sharp needle, and at the same time needle is manipulated and placed to a predetermined location. The solvent evaporates during the manipulation path leaving a solid and cylindrical single fiber. A liquid polymer fiber bridge between the probe tip and a substrate is maintained when pulling the probe from the surface with controlled speed and position. Fibers are also produced in a continuous manner. In this technique, polymer solution is continuously extruded through an orifice onto a substrate, where substrate either spins or stays stationary depending on the fabrication process.
Some key objectives of this project include:
Benefits: One of the most significant barriers for enabling the breakthroughs promised by nano-technology is mass production of nano-scale structures, devices, and systems. Therefore, novel manufacturing processes at the micro/nano-scale are indispensable for the commercialization of future nano-scale devices, circuits, man-made materials, sensors, etc. Due to fiber's enhanced properties such as high surface area to volume ratio and multifunctionality, this micro/nano-fiber pulling technology would have wide applications in nano-circuit interconnects by using conductive nano-fibers, prototyping novel nano-electronic devices by using conductive/semi-conductor/non-conductive polymer fiber structures, 3D polymer fiber-based nano-actuators, photonic devices, novel bio-nano-sensors, smart materials, etc. Moreover, analysis of the polymorphism and morphology of the polymer fibers will lead to novel composite materials.
- Development of an autonomous and repeatable three-dimensional fiber pulling technique at reduced length scales (sub-micron and sub-100 nanometer domains)
- Compare and tabulate fiber forming capabilities of various polymer/solvent combinations
- Develop polymer pulling numerical and analytical models for reduced length scales and validate them against experimental results.
- Massively parallel fiber manufacturing and fiber network formation.
- Development of mechanical and structural analysis techniques and compare with the bulk counterparts (film structures). Also, analysis of the polymorphism, morphology and molecular orientation of the polymer fibers.
- Dynamic and adhesion measurements using the laser Laser Doppler Vibrometry (LDV) and Atomic Force Microscopy (AFM) of the fabricated fibers in order to understand the wave propagation and adhesion-induced fiber collapse in the fiber networks.
- Produce and test the smart materials and structures using both crystalline and amorphous polymers.
A. S. Nain, F. Chung, M. Rule, J. A. Jadlowiec, P. G. Campbell, C. Amon, and M. Sitti, ''Microrobotically Fabricated Biological Scaffolds for Tissue Engineering,'' Proc. of the IEEE Robotics and Automation Conference, Rome, Italy, April 2007, in press.
A. Nain, J. Wong, C. Amon, and M. Sitti, ''Drawing suspended polymer micro/nanofibers using glass micropipettes,'' Applied Physics Letters, vol. 89, no.18, pp. 183105-7, 2006. Also appeared on the Virtual Journal of Nanoscale Science & Technology, vol. 14, no. 20, November 13, 2006. pdf
A. Nain, C. Amon, and M. Sitti, ''Proximal Probes based Nanorobotic Drawing of Polymer Micro/Nanofibers,'' IEEE Trans. on Nanotechnology, vol. 5, no. 5, pp. 499-510, Sept. 2006. pdf
A. Nain, C. Amon, and M. Sitti, ''Polymer Micro/Nanofiber Fabrication using Micro/Nanopipettes,'' Proc. of the IEEE Nanotechnology Conference, pp. 366-369, Nagoya, Japan, July 2005.
A. Nain and M. Sitti, ''Micro/Nano Polymer Fiber Manufacturing using Atomic Force Microscope: Key steps to Nano-manufacturing'', Proc. of the IEEE Mechatronics Conference, Turkey, June 2004.
A. Nain, D. Goldman, and M. Sitti, ''Three-Dimensional Nanoscale Manipulation and Manufacturing using Proximal Probes: Controlled Pulling of Polymer Micro/Nanofibers'', Proc. of the IEEE Robotics and Automation Conference, New Orleans, LA, USA, April 26, 2004. (Best Manipulation Paper Nomination)
A. Nain and M. Sitti, ''3-D Nanoscale Manufacturing by Nanoprobes based Controlled Pulling of Liquid Polymers,'' IEEE Nanotechnology Conference, pp. 60-63, San Francisco, USA, August 2003. pdf