Interatomic interaction potentials are compared using a molecular dynamics modeling method to choose the simplest, but most effective, model to describe the interaction of copper nanoparticles and graphene flakes. Three potentials are considered: (1) the bond-order potential; (2) a hybrid embedded-atom-method and Morse potential; and (3) the Morse potential. The interaction is investigated for crumpled graphene filled with copper nanoparticles to determine the possibility of obtaining a composite and the mechanical properties of this material. It is observed that not all potentials can be applied to describe the graphene–copper interaction in such a system. The bond-order potential potential takes into account various characteristics of the bond (for example, the angle of rotation and bond lengths); its application increases the simulation time and results in a strong interconnection between a metal nanoparticle and a graphene flake. The hybrid embedded-atom-method/Morse potential and the Morse potential show different results and lower bonding between graphene and copper. All the potentials enable a composite structure to be obtained; however, the resulting mechanical properties, such as strength, are different.

Graphene aerogels with high surface areas, ultra-low densities, and thermal conductivities have been attracted a lot of attention in recent years. However, considerable difference in their deformation behavior and mechanical properties lead to their poor performance. The problem can be solved by preparing graphene aerogel of given morphology and by control the properties through the special structure of graphene cells. In the present work, molecular dynamics simulation is used to overview the mechanical properties of four different morphologies of graphene aerogel: honeycomb, cellular, lamellar and randomly distributed graphene flakes. All the structures are considered under uniaxial compression and tension with the detailed analysis of the deformation behavior. It is found that cellular structures have much better compressibility and elasticity. During both compression and tension, cellular structures can be transformed from one to another by controlling the compression/tensile direction. The highest strength and fracture strain are found for the lamellar GA under tension along the direction perpendicular to the alignment of the graphene walls. This reveals that the mechanical properties of graphene aerogels can be controlled by enhancing the structural morphology. The obtained results is the contribution which provide the insights into recent developments concerning the design of carbon-based structures and their application.

Анализ применимости межатомных потенциалов для решения задач различной направленности представляет большой интерес, поскольку именно межатомный потенциал определяет результат моделирования. В данной работе методом молекулярной динамики исследуется взаимодействие листа графена с наночастицей титана с использованием двух разных межатомных потенциалов – потенциала Морзе и потенциала Терсоффа. Следует отметить, что потенциал Терсоффа описывает все три вида взаимодействий в системе (С-С, С-Ti, Ti-Ti), а потенциал Морзе используется для описания взаимодействия С-Ti, а взаимодействие С-С описано потенциалом AIREBO.При этом рассматривается два набора параметров потенциала Морзе, по-разному воспроизводящих взаимодействие в системе. Разница в параметрах потенциалов возникает при их подгонке под решение определенных задач. Морфология рассмотренного материала выбрана исходя из задачи дальнейшего моделирования композитного материала на основе листов графена и наночастиц металла. Показано, что один из применяемых наборов параметров Морзе хорошо воспроизводит осаждение графена на металлическую подложку, однако не может воспроизводить взаимодействие графена и наночастицы. Анализ производится на основе вычисления энергии взаимодействия в системе и структурных состояний. Наилучшее отображение реального физического взаимодействия наночастицы титана и графена позволяет получить потенциал Терсоффа, однако второй набор параметров потенциала Морзе также может быть использован для проведения подобных расчетов. Взаимодействие наночастицы титана и графена является достаточно сильным и наночастица титана легко прикрепляется к чешуйке графена, после чего «обволакивается» чешуйкой графена.

Honeycomb graphene aerogels offer a combination of graphene wall qualities, such as mechanical strength and binding, and the unique, engineered architecture of honeycombs. The honeycomb structure opens new opportunities for property modification, such as reinforcement with metal nanoparticles, which can increase strength and electrochemical performance. This study uses molecular dynamics simulations to examine the reinforcement of graphene honeycomb aerogels containing 2.7% and 5.8% randomly distributed Ni or Al nanoparticles. Metal nanoparticles considerably increase the resistance to compression: stress increase occurred for aerogels with Al nanoparticles at a density of 1.3 g/cm³, while for aerogels and filled with Ni, stress increase occurred at 2.0 g/cm³. The strengthening mechanism is volume repulsion when Al NPs repel the graphene cell walls, while Ni nanoparticles easily spread along the cell walls and provide less compression resistance, analogous to pure graphene aerogels. The tensile properties remained unaffected by the presence of either nanoparticle type since the same deformation mechanism (cell collapse) occurred for all aerogels. The maximal ultimate tensile strength achieved was 160 GPa. Temperatures ranging from 300 to 3000 K slightly affected the strength of all aerogels.