Thermal gradient directed assembly of block copolymer thin films characterized using X-ray and neutron scattering techniques


Nathaniel J. Fredin, Kevin G. Yager, and Ronald L. Jones


Polymers Division, Materials Science and Engineering Laboratory,

National Institute of Science and Technology, Gaithersburg, MD 20899


The use of block copolymer (BCP) thin films as resists for nanopatterning provide a promising platform for “bottom-up” approaches to next generation data storage devices.  The covalent linkage between the two chemically dissimilar blocks in each polymer chain limits the length scale over which phase separation can occur to O(1-100) nm, leading to a variety of mesophases with periodicities at the nanoscale.


Several approaches have been adopted to overcome kinetic barriers that lead to defects in the periodic order of BCP films, including solvent annealing, application of electric fields, and chemical and topographic templating of the substrate.  Another class of approaches involves the use of moving thermal gradients to enhance order and direct orientation.  Here, we present the results of experiments aimed at elucidating the role of thermal gradients on ordering in BCP thin films, using a combination of X-ray and neutron scattering techniques to characterize film structure resulting from various thermal processing approaches.