Thermomechanical analysis of 3-, 4-, and 5-carbophenes using reactive MD simulations*

Carbophenes are a novel class of two-dimensional hydrocarbons composed of alternating units of cyclobutene and cyclohexatriene. Using a combination of reactive force field molecular dynamics simulations in high throughput calculations and data science methods, we explore the temperature at which the carbophenes melt and their area thermal expansions. Although the methods produce differing results, trends are shared across models. The NPT and AHNPT demonstrate that carbophenes are stable to over 1200 K, but the NPT results tend to show the onset of melting at a slightly higher temperature than the AHNPT results. Like graphene, carbophenes contract as temperature increases when heated from 10 K to about 1500 K, as shown by the negative slope in the AHNPT models. The NPT models show more significant variation, with 3-carbophene and 5-carbophene expanding over 250 K to 450 K and 750 K to 1550 K, respectively. Since carbophenes are expected to have many practical applications, from molecular filters to nanofluidics, the effect of temperature on their mechanical properties must be considered in future engineering and research.