Banca de DEFESA: JAILSSON SILVA LIMA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JAILSSON SILVA LIMA
DATE: 08/08/2022
TIME: 14:00
LOCAL: Google Meet
TITLE:

Mechanical properties of carbon and boron nitride nanostructures: a molecular dynamics study

KEY WORDS:

Graphene, Hexagonal boron nitride, Hybrid nanostructures, Mechanical properties, Molecular Dynamics

PAGES: 125
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

The discovery of graphene and its exceptional properties has motivated research on two-dimensional (2D) materials for over a decade. Since then, several other 2D materials with diverse properties have been discovered, such as hexagonal boron nitride (h-BN). More recently, two-dimensional materials have been combined into hybrid structures, leading to the creation of solids with adjustable properties. In this document, the mechanical properties of hybrid nanostructures composed of graphene and h-BN were investigated using classical molecular dynamics. Two types of arrangements were considered: (i) square sheets of graphene containing circular and hexagonal h-BN domains and (ii) square sheets of h-BN containing circular, hexagonal, triangular and double triangular graphene domains. The results obtained here show that, for both types of structures, the Young's modulus of the hybrid structure depends essentially on the fraction of h-BN and graphene in the structure, with Young's modulus values decreasing linearly as the concentration of h-BN increases in (i) and increasing with increasing graphene in (ii). We also analyze the temporal evolution of the fracture patters and of the stress concentration during the simulations. From this analysis we conclude that the fracture always starts in the interface region between graphene and h-BN, because it was found that the B-C and C-N bonds are weaker than the C-C and B-N bonds. Finally, we observe for both types of arrangements that the mechanical properties of the hybrid structures are not altered when the sheet length and the domain diameter are increased proportionally. This indicates that our results may be valid for much larger structures than those tested here, such as those that are synthesized experimentally.

COMMITTEE MEMBERS:
Externo à Instituição - ALEXANDRE FONTES DA FONSECA - UNICAMP
Interno - 1519258 - DORY HELIO AIRES DE LIMA ANSELMO
Presidente - 2411793 - LEONARDO DANTAS MACHADO
Interno - 1294916 - MADRAS VISWANATHAN GANDHI MOHAN
Externo à Instituição - SERGIO ANDRÉ FONTES AZEVEDO - UFPB