Seminar: Molecular Simulations of Epoxy Networks and Nanocomposites

The subject of the present seminar is the detailed investigation of structural, mechanical, topological and local-segmental properties of epoxy networks of different crosslinking degrees, as well as of interfaces between these networks and graphenic (inclusion) materials. Using atomistic simulations as the principal tool, an epoxy in the bulk is first studied. Following that, the thermodynamics, structure, and interfacial kinetics of a nanocomposite consisting of parallel single layers of pristine, defective, or chemically modified graphene enclosed in the epoxy are investigated.

The study of the nanocomposite interface is targeted at the failure of adhesion brought about by imposition of shear deformation. A new methodology is developed which extends the Boltzmann-Arrhenius-Zhurkov model and it is applied in the prediction of the mechanical response of the material under shear stress. Testing the methodology for the three types of graphenic inclusions over a wide variety of temperatures and stresses, favorable agreement with experimental studies is observed and the factors controlling adhesion at the interface are elucidated.

Spyridon (Spyros) Kallivokas was awarded his PhD in Computational Material Science and Engineering from the National Technical University of Athens (NTUA) in 2020. Thereafter, he continued with post-doctoral research at Charles University (Prague), Jeyrovsky Institute of Physical Chemistry (Prague). Centre of Research and technololgy (CERTH) in Thessaloniki, and now at the Institute of Communication and Computer Systems and in NTUA.
He also serves as a visiting assistant professor in the Materials Science and Technology department at the University of Crete.

His main research activity focuses on structural, dynamical and mechanical properties of polymer networks, nanocomposites and biopolymers.