Formation of Block Copolymer Micelles in Solution:  A Monte Carlo Study of Chain Length Dependence

Abstract

Short block copolymers in a selective solvent (bad for A-block, good for B-block) are modeled by flexible bead-spring chains, where beads interact with short-range Morse potentials of variable strength. In particular, treating the strength E AA of attraction between monomers of the A-block as a variable, we study the mass distribution of the micelles that are formed under conditions that correspond to the vicinity of the critical micelle concentration (cmc). Choosing a composition f ) NA/N ) 1 /4 for the block copolymers, we vary their chain length N from N ) 4 to N ) 32. Only such relatively short chains can be used in thermal equilibrium, since the relaxation times of the system increase dramatically with increasing length. We show that in the regime of parameters accessible to our study, the number of chains per micelle is rather small and almost independent of chain length, implying that the core radius scales as NA 1/3 in this regime. We compare our results with existing theoretical predictions and with experiments.

Inferring bulk self-assembly properties from simulations of small systems with multiple constituent species and small systems in the grand canonical ensemble

“…[15][16][17] With increased computing power and improved simulation techniques, it has become possible to simulate mesoscale models that reproduce such self-assembling behaviour. In recent years mesoscopic models have been used to assemble micelles, [18][19][20][21][22][23][24][25][26][27][28][29][30][31] vesicles, 29,32,33 hollow shells of specific symmetry analogous to virus capsids [34][35][36][37][38][39][40][41][42] and aggregates of particles which resemble protein clusters. 43 Additionally, reflecting the growth of DNA nanotechnology, 44 many coarse-grained models of DNA assembly have recently been proposed.…”

Morphological Similarities between Single-Walled Nanotubes and Tubelike Structures of Polymers with Strong Adsorption Affinity to Nanowires

“…The cutoff is chosen to be r c =2.5σ. Covalently bonded adjacent monomers in the linear polymer chain interact via the finitely extensible nonlinear elastic (FENE) potential, which has the form [17,18] …”

Developments in Wang-Landau simulations of a simple continuous homopolymer

“…where the first term represents the bonded energy, summed over all N − 1 bonds using the bond potential U Bond (l i ), which is a combination of a finitely extensible nonlinear elastic (FENE) potential [2,13] and a Lennard-Jones potential.…”