Efficient Surface Neutralization and Enhanced Substrate Adhesion through Ketene Mediated Crosslinking and Functionalization

Jung, H.; Leibfarth, F.A.; Woo, S.; Lee, S.; Kang, M.; Moon, B.; Hawker, C.J.; Bang, J.
Adv. Func. Mater.
23, 1597-1602

Balancing the interfacial interactions between a polymer and substrate is
one of the most commonly employed methods to ensure the vertical orientation
of nanodomains in block copolymer lithography. Although a number of
technologies have been developed to meet this challenge, there remains a
need for a universal solution for surface neutralization that combines simple
synthesis, fast processing times, generality toward substrate, low density of
fi lm defects, and good surface adhesion. The chemistry of ketenes, which
combines highly effi cient polymer crosslinking through dimerization and surface
adhesion through reaction with the substrate, is shown to be well suited
to the challenge. The versatile chemistry of ketenes are accessed through the
post-polymerization of Meldrum’s acid, which can be easily incorporated into
copolymers through controlled radical polymerization processes. Further, the
Meldrum’s acid monomer is synthesized on a large scale in one step without
the need for chromatography. Processing times of seconds, low defect density,
simple synthetic procedures, and good substrate adhesion make these
materials attractive as robust block copolymer neutralization layers.