University of Connecticut |
Polymer Program SeminarNano-patterning in Polymeric and Biological Materials Based on Atomic Force Microscopy Electrostatic Nanolithography Friday, November 18, 2005 11:00 am , IMS Room 20 Atomic force microscopy electrostatic nanolithography (AFMEN) technique is based on manipulation of nano-amounts of dielectrics in strong 108-1010 Vm-1 electric field. In polymer films of different physical-chemical properties AFMEN produces erasable nano-structures that are 10–300 nm in diameter and 0.5–20 nm in height through Joule heating of polymeric molecules between a conductive AFM tip and substrate followed by electrostatic attraction of the softened polymer towards the tip. The technique can be implemented in three distinct modes: amplitude-modulated AFMEN, z-lift electrostatic nanolithography (ZEN), and “friction” mode resulting in electrification at the nanoscale. Among all experimentally controllable parameters, the bias voltage is mostly critical. The application of high voltage (above -35 V) results in nanostructures formation of 0.5-50 nm height and 15-100 nm width. The nanostructures width in “friction” mode was obtained at resolution 10-30 nm using commercially available Micromasch tips of 40 nm in diameter. The tip-surface separation is essential in ZEN. The spring constant of cantilever including the protocol of vertical manipulation is critical for the height of nanostructures formation. Other important parameters include the lateral velocity of the AFM tip, and ambient humidity. We discuss AFMEN for potential data storage applications in polymeric materials. Additionally, AFMEN manipulates bundles of Wiseana Iridovirus and produces noticeable changes in capsids composing individual virions.
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