S4.2
Molecular dynamics simulation of polymer nanocomposites:
current achievements and future opportunities
Jun Liu1, Jianxiang Shen1, Yangyang Gao1, Liqun Zhang1,2
1
Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials
and 2 State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical
Technology, Beijing 100029, People’s Republic of China.
Abstract
Besides experiment and theory, computer modeling and simulation has already
become the third important research approach, because of its unique advantages
such as convenience and intuition. In this talk I will systematically introduce research
achievements of polymer nanocomposites (PNCs) through molecular dynamics
simulation, carried out in our research group. First, we studied the dispersion and
aggregation behavior of bare nanoparticles(NPs) with different geometries such as
spherical, sheet-like and rod-like under quiescent and shear cases. To model small
ligands used in experiments to realize better dispersion, we investigated the dispersion
of NPs end-grafted with polymer chains by varying the grafted chain length and grafting
density. Second, we probed the translational and relaxation dynamics at the chain and
segmental length scales of the interfacial regions, hoping to elucidate whether “glassy
layers” exist around NPs. Third, we simulated the enhancement of the Young’s modulus,
stress-strain and fracture toughness induced by NPs, providing a molecular reinforcing
mechanism. Fourth, the famous “Payne effect”, namely the decrease of the storage
modulus as a function of the strain amplitude was examined, uncovering the underlying
reason responsible for this non-linear behavior, and how the introduced carbon nanosprings can effectively reduce the dynamic hysteresis of PNCs is as well illustrated.
Fifth, we also simulated the formation of conductive network. Lastly, future simulation
challenges and opportunities of PNCs are presented. In general, computer modeling and
simulation is shown to have the capability to obtain some fundamental understanding
of PNCs at the molecular level, in hopes of providing some design basis and principles for
synthesizing and preparing multi-functional and high performance PNCs.
References
1. Jun Liu, Yong-Lai Lu, Ming Tian, Fen Li, Jianxiang Shen, yangyang Gao, Liqun Zhang*; The Interesting Adjusting
of “Nanospring” on the Viscoelasticity of Elastomeric Polymer Materials: Simulation and Experiment; Advanced
Functional Materials; 23, 1156-1163(2013).
2. Jun Liu, Liqun Zhang*, Dapeng Cao, Jianxiang Shen, yangyang Gao; Computational simulation of elastomer
nanocomposites: current progress and future challenges; Rubber Chemistry and Technology; 85, 450-481(2012).
(An invited review)
3. Jianxiang Shen, Jun Liu, Yangyang Gao, Xiaolin Li, Liqun Zhang*; Elucidating and tuning the strain-induced nonlinear behavior of polymer nanocomposites: a detailed molecular dynamics simulation study; Soft Matter, 10,
5099-5113(2014).
4. Zhenhua Wang, Jun Liu, Sizhu Wu, Wenchuan Wang and Liqun Zhang; Novel percolation phenomena and
mechanism of strengthening Elastomers by nanofillers; Physical Chemistry Chemical Physics, 10, 30143030(2014).
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Short Biography
Jun Liu is an associate professor in the department of Materials Science and Engineering
of Beijing University of Chemical Technology, and he mainly focuses on simulating
the structure, dynamics, static and dynamic mechanical properties of polymer
nanocomposites through molecular dynamics simulation. He has published over nearly
twenty peer reviewed papers, such as Advanced Functional Materials, Macromolecules,
Soft Matter, Langmuir and so on.
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