Polymer Nanocomposites (PNC) are a new class of materials characterized by their large interfacial areas between the host
polymer and nanofiller. This unique feature, due to the size of the
nanofiller, is understood to be the cause of enhanced
mechanical, electrical, optical, and barrier properties observed of
PNCs, relative to the properties of the unfilled polymer. This
interface can determine the miscibility of the nanofiller in the
polymer, which, in turn, influences the PNC's properties. In addition,
this interface alters the polymer's structure near the surface of the
nanofiller resulting in heterogeneity of local properties that can be
expressed at the macroscopic level.
Considering the polymer-nanoparticle interface significantly
influences PNC properties, it is apparent that some atomistic level of
detail is required to accurately predict the behavior of
PNCs. Though an all-atom simulation of a PNC would be able to
accomplish the latter, it is an impractical approach to pursue even with
the most advanced computational resources currently available.
In this contribution, we develop
(1) an equilibrium coarse-graining method to predict nanoparticle
dispersion in a polymer melt, (2) a dynamic coarse-graining method
to predict rheological properties of polymer-nanoparticle melt
mixtures, and (3) a numerical approach that includes interfacial
layer effects and polymer rigidity when predicting barrier properties
of PNCs.
In addition to the above, we study how particle and polymer
characteristics affect the interfacial layer thickness as well as how
the polymer-nanoparticle interface may influence the entanglement
network in a polymer melt. More specifically, we use a mean-field
theory approach to discern how the concentration of a semiflexible
polymer, its rigidity and the particle's size determine the
interfacial layer thickness, and the scaling laws to describe this
dependency. We also utilize molecular dynamics and simulation
techniques on a model
PNC to determine if the polymer-nanoparticle interaction can influence
the entanglement network of a polymer melt. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/ETD-UT-2010-12-2099 |
| Date | 02 February 2011 |
| Creators | Khounlavong, Youthachack Landry |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Type | thesis |
| Format | application/pdf |
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