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Bernardo M. Aguilera Mercado Current Research

Research Focus

Elastomers, basic structural elements of rubbers and gels, are polymer networks above the glass transition temperature formed by flexible chains connected through multifunctional nodes called cross-links. The main characteristic of elastomers is their rubber-like elastic behavior; in other words, they not only can undergo significant deformations but also return to their original states after having removed the causative agent. The mechanical properties of these polymers, such as elastic modulus, toughness, ultimate strain and strength, usually determine their commercial use (e.g., in structural materials).

Molecular simulation techniques can explore these polymer networks and aid answering several open questions about their elastic behavior. This research pretens to consider multimodal networks (beyond bimodal), including simulations of both formation and deformation (swelling and uniaxial). In addition, an effective simulation tool based on Molecular Dynamics (MD) techniques for network deformation is being developed.

Having this new tool allows the design of more realistic computer experiments that can measure the ultimate strain and strength, and consequently, the toughness. Using MD codes for network deformation is also useful to generate stress-strain curves via iso-strain simulations for highly regular polymer (entanglement free) networks and explore, in more detail, their novel elastic behavior and the underlying free-energy landscape. In a further stage of this work, polymer networks made of copolymers will be modeled so as to elucidate the effect of disparate energetic interactions on the network microstructure and, therefore, on its tensile properties.

Fig.1 shows an overview of the relationships to be studied in the process of network design.