Effects of Graphene Oxidation on Interaction Energy and Interfacial Thermal Conductivity of Polymer Nanocomposite: A Molecular Dynamics Approach

Abstract

Interfacial characteristics of polymer nanocomposites represent a crucial aspect to understand their global properties and to evaluate the interaction between nanofillers and matrix. In this work we used a molecular dynamics (MD) approach to characterize the interfacial region at the atomistic scale of graphene-based polymer nanocomposites. Three different polymer matrixes were considered, polylactic acid (PLA), polypropylene (PP) and epoxy resin (EPO), which were reinforced with three types of graphene fillers: pristine graphene (G), graphene oxide (GO) and reduced graphene oxide (rGO). In particular, the compatibility of the nanofillers in polymer matrixes were evaluated in terms of the interaction energy, while the interfacial thermal resistance (Kapitza resistance) between matrices and fillers was calculated with a nonequilibrium molecular dynamics (NEMD) method. Results showed that the oxidation degree plays an important role on the studied properties of the interfacial region. In particular, it was observed that the Kapitza resistance is decreased in the oxidized graphene (GO and rGO), while interaction energy depended on the polarity of the polymer matrix molecules and the contribution of the Coulombic component.

From two‐dimensional materials to polymer nanocomposites with emerging multifunctional applications: A critical review

“…RNEMD simulations have demonstrated that functionalization, both noncovalent and covalent, may improve ITC between 2DM and polymer matrix due to stronger interfacial interactions and greater phonon vibrational match, even though it degrades the TC of pristine graphene by orders of magnitude. [ 228 ] This effect is presented in Figure 16A, and it has been experimentally verified when coupling h‐BN to silane agents to improve epoxy's TC, achieving an enhancement of more than 500% at 30 wt%. [ 229 ]…”

Structure and properties of polymer/two-dimensional nanomaterials studied via molecular dynamics simulation: a review

“…The interfacial thermal resistance exhibits the same behavior/tendency in the three polymers (PLA, PP, and epoxy): graphene > rGO ≈ GO. 86 It was also observed that the presence of functional groups in the graphene, in the form of oxidation (hydroxyl and oxirane groups), increased the interfacial thermal conductivity.…”

Probing the Influence of Surface Chemical Functionalization on Graphene Nanoplatelets-Epoxy Interfacial Shear Strength Using Molecular Dynamics

“…More specifically, the remarkable engineering properties of graphene/epoxy nanocomposites have attracted the interest of both researchers and stakeholders. Therefore, such nanocomposites have been utilized to further improve the mechanical properties of traditional carbon fiber/epoxy composites by fabricating carbon fiber/graphene/epoxy hybrid composites [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Apart from structural materials, graphene-based materials find application in various fields such as ultra-narrow sensors for biomolecules detection [ 11 ] and electrochemical sensors for detecting harmful chemicals released into the air from flame retardants [ 12 ], modulators and detectors fabricated as a two-dimensional material [ 13 ], and water-treatment applications to clean-up impurities in water [ 14 ].…”