Abstract
Summary: Crystallization, melting and annealing of nanoparticles of tetracontane were simulated via a Monte Carlo method on the second nearest neighbor diamond (2nnd) lattice by including shortβ and longβrange interactions. Nanoparticles can be obtained from an equilibrated tetracontane melt by increasing three periodic lengths to values that are effectively infinite. Nanoparticles, which contain 155 chains of C~40~H~82~, have been produced. After a deep quench from 473 K to 298 K, the crystallization process was investigated by the evolution of the density profile, fraction of bonds in the trans state, and the orientational order parameter. The vicinity of the center is less dense and less well ordered than portions of the nanoparticle located further from the center. The crystals form first in the region close to the surface. Each nanoparticle usually contains multiple crystalline domains. A melting phenomenon was observed at a temperature about 365 K when the nanoparticle crystal was heated. Annealing of the multiple domain crystal at 360 K can transform the structure to a more regular one without a grain boundary.
Snapshot of the final structure containing a single domain crystal after 20 million MCS.
imageSnapshot of the final structure containing a single domain crystal after 20 million MCS.