Multicore Unimolecular Structure Formation in Single Dendritic–Linear Copolymers under Selective Solvent Conditions

Abstract

The conformational and thermodynamic properties of single dendritic–linear copolymers are investigated by analytical models and computer simulations. Applying poor solvent conditions on the dendritic part, these molecules are known to form single unimolecular micelle-like structures. A mean-field model applying the Daoud–Cotton approach and a surface tension argument is presented and suggests the splitting of the unimolecular single-core structure into a multicore structure with increasing dendrimers generation and decreasing solvent selectivity. Monte Carlo simulations utilizing the bond fluctuation model with explicit solvent are performed which show the formation of multicore structures for trifunctional codendrimers of different generations and spacer lengths with linear chains attached to the terminal groups. These findings are aimed to understand the physics of spontaneous self-assembly of codendrimers in various well-defined macro-conformations under change of environmental conditions with potential applications such as drug delivery systems.

Multicore Assemblies from Three-Component Linear Homo-Copolymer Systems: A Coarse-Grained Modeling Study

“…On the theory side, Wang et al [ 34 ], via a self-consistent field theory approach, have studied multicore micelle formation from linear ABC tri-block ter-polymers containing a solvophilic midblock and two mutually incompatible solvophobic head groups. In another study, Wengenmayr et al [ 51 ], via a mean-field model, observed the splitting of unimolecular single-core micelles of dendritic-linear copolymers to a multicore structure, with increasing dendrimer generation and decreasing solvent selectivity. On the computational side, DPD simulations which employ particle-based, mesoscale level modeling of the polymer chains and their assembly and dynamics, have turned out to be an adaptable and reasonably successful tool for examining the formation and assembly responses of polymeric micelles [ 46 , 52 , 53 , 54 ].…”

Formation of a Hollow Core in Dendrimers in Solvents

“…Another case of pseudocavity was studied in copolymer dendrimers [ 95 ] by Monte‐Carlo simulations. It was shown that the formation of a hollow core for higher ( G > 6) generations in copolymer dendrimers is possible due to poor quality of solvent for inner segments and the segregation effect between terminal and inner segments (see green curves in Figure b,c).…”

“…Reproduced with permission. [ 95 ] Copyright 2016, American Chemical Society. “Pseudocavity” case, since the minimum density in the inner volume of copolymer dendrimer for selective solvent (green in part d)) is equal or higher than the density of copolymer dendrimer for nonselective solvent (green in part b), i.e., 0.1 ≥ 0.2/S 4/5 .…”

“…[ 87–90 ] One of the most straightforward ways to form a hollow core inside a dendrimer is to use terminal groups which pervasion to the inner volume of the molecule is limited, for instance, due to steric reasons (too large volume of terminal groups [ 91 ] or low compatibility with other segments of dendrimer). Both, theory [ 92–95 ] and experimental studies [ 96,97 ] presented in Section 3 of this review suggest a realistic example of hollow core formation in codendrimer with different terminal and inner segments which can be experimentally detected using NMR. At the end of this review, the main results are comprised in Summary.…”

Modeling of Nonlinear Optical Phenomena in Host-Guest Systems Using Bond Fluctuation Monte Carlo Model: A Review

“…In spite of being a non-specific model of polymer dynamics, the BFM was successfully used to study a large variety of physical effects in two- and three dimensions like, e.g., static [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] and dynamic [ 18 , 30 , 31 , 32 , 33 ] properties of linear chains, polymer rings [ 27 , 34 ], polymer blends and interfaces [ 35 , 36 ], gels and networks [ 37 ], glass transition [ 38 , 39 , 40 ], polymer blends [ 41 ], (co)polymers at surfaces [ 42 ], polymer brushes in good solvents [ 43 , 44 , 45 , 46 , 47 , 48 , 49 ], polymer thin films [ 50 , 51 , 52 ], equilibrium polymers [ 29 , 53 , 54 ], general self-assembly [ 55 , 56 , 57 ], networks and gel point [ 58 , 59 , 60 , 61 ], olympic gels [ …”