(441e) Effect of Graphene and Graphene Oxide on the LCST of PNIPAM

Authors: 
Berry, C., Virginia Polytechnic and Institute and State University
Deshmukh, S. A., Virginia Polytechnic Institute and State University

Poly(N-isopropylacrylamide)
(PNIPAM) is a thermo-sensitive polymer displaying a coil-to-globule transition
above its lower critical solution temperature (LCST) of 305 K.  As its LCST is
close to the physiological temperature, PNIPAM is an attractive candidate for
in-vivo applications such as drug delivery.  Graphene nanostructures have also
shown great potential in the area of biomedicine with applications ranging from
drug delivery to tissue engineering.  Additionally, complexes of graphene oxide
and various aromatic drugs have yielded vastly improved water solubility
allowing for increased efficacy.  In this work, we have conducted all-atom
molecular dynamics (MD) simulations of a PNIPAM chain consisting of 30 monomer
units along with sheets of either graphene or graphene oxide in the presence of
water.  All simulations were carried out at 325 K and 275 K, which are above
and below the LCST of PNIPAM, respectively.  The impact of sheet width and its
initial angle with respect to PNIPAM on the LCST of PNIPAM is investigated.