The Controlled Evolution of a Polymer Single Crystal
Xiaogang Liu,1*
Yi Zhang,1*
Dipak K. Goswami,2
John S. Okasinski,2
Khalid Salaita,1
Peng Sun,1
Michael J. Bedzyk,2
Chad A. Mirkin1
We present a method for controlling the initiation and kinetics of polymer crystal growth using dip-pen nanolithography and an atomic force microscope tip coated with poly-DL-lysine hydrobromide. Triangular prisms of the polymer epitaxially grow on freshly cleaved mica substrates, and their in-plane and out-of-plane growth rates can be controlled by raster scanning the coated tip across the substrate. Atomic force microscope images were concomitantly recorded, providing a set of photographic images of the process as it spans the nanometer- to micrometer-length scales as a function of environmental conditions.
1 Department of Chemistry and Institute for Nanotechnology, Northwestern University, Evanston, IL 60208, USA.
2 Department of Materials Science and Engineering and Nanoscale Science and Engineering Center, Northwestern University, Evanston, IL 60208, USA.
* These authors contributed equally to this work.
To whom inquiries pertaining to crystallography should be addressed. E-mail: bedzyk{at}northwestern.edu 
To whom all other correspondence should be addressed. E-mail: camirkin{at}chem.northwestern.edu
