Effect of Bond Tangency/Gap on the Crystallization of Athermal Polymer Packings ^†

We present results from extensive Monte Carlo simulations on dense and nearly-jammed packings of chains of hard spheres of uniform size [1]. Local environment and similarity to specific crystal structures are gauged through the crystallographic element norm (CCE) metric [2]. We study the role of bond constraints on the packing behavior and structural characteristics of polymer assemblies: by increasing the bond tolerance (bond gaps), we observe accelerated crystal nucleation and growth which in turn lead to a wealth of ordered morphologies [3]. In their majority, crystals structures with bond gaps are significantly different from the random hexagonal close packing which prevails in the strict tangent limit [4,5,6]. In general, bond tangency shifts the occurrence of the phase transition to higher packing densities compared to monomers [7] and to chains with bond gaps. Based on these findings, by using simple geometric arguments, we explain the role of rigid and flexible constraints in the packing behavior (crystal nucleation and growth) of general atomic and particulate systems.