Supriya Gupta (Dr. Paresh Chokshi)
9th November 2016, Wednesday, 04:00- 04:30 pm (25+5 mins),
ChE Seminar hall
An emerging application of polymer nanocomposites is to generate
selfassembly of nanoparticles leading to novel nanoscale materials
with enhanced properties. The micro‐phase separated morphologies in
a melt of diblock copolymer are potential candidates to provide template
for the selfassembly of nanoparticles for various
nano-technological applications. As particle-based simulation
techniques are computationally intensive for a large system, we employ the
selfconsistent field theory (SCFT) to examine the localization of
functionalized nanoparticles in twodimensional lamellar phase of diblock
copolymer. The self-consistent field theoretical model is built from
the microscopic description taking into account the molecular interactions
contributed by both intra and inter-chain potentials. The
spherical nanoparticles are grafted with polymeric chains chemically
identical to one of the blocks of the diblock copolymer. As particles are
much smaller than the domain size of the lamellar microphase of the
diblock copolymer, the grafted nanoparticles are treated as star
molecules. The localization of particles is governed by the conformational
entropy of the polymeric chain, in addition to the interaction between the
particles and matrix. At low concentrations, the particles are found to
segregate at the interface between two polymeric domains. However, as
particle concentration is increased, the particles tend to preferentially
assemble near the center of the polymeric domain compatible with the
grafted chain. The role of grafting density and particle size on the
positioning of the particles in ordered morphology of diblock copolymer is
examined. By grafting particles with diblock copolymer chemically
identical to the matrix, the localization of the nanoparticles can be
tuned by varying the fraction of each block in the grafted chain. Further,
we also examine the localization of functionalized nanoparticles in a
symmetric triblock copolymer. The interplay between the enthalpic and
entropic contributions to free energy gives rise to rich behavior in
particle selfassembly. The comprehensive understanding of various factors
affecting the localization of nanoparticles in polymeric domains, like
grafting density, particle size and particle volume fraction, enable us to
control the particulate assembly for desirable material properties.