Nitroxide‐Mediated Radical Polymerization in Dispersed Systems: Compartmentalization and Nitroxide Partitioning

Abstract

Cover: The image presents the relaxation of a melt of dense polymer globules into a standard entangled melt. Short chains expand isotropically in space while very long chains relax by reeling out ends, as illustrated by the timedependent ratio of the squared end-to-end distance and radius of gyration (inset). Further details can be found in the article by T. Vettorel and K. Kremer* on page 44. Contents Growing Interest in Theory and Simulations S. SpiegelMacromol. Theory Simul. 2010, 19, 7-9 Full Paper: Compartmentalization and nitroxide partitioning in nitroxidemediated radical polymerization in dispersed systems have been investigated by modeling and simulations. Compartmentalization comprises the segregation effect on termination and the confined space effect on deactivation. Under certain conditions, it is possible to obtain an improvement in both control and livingness.

Nitroxide‐Mediated Radical Polymerization of Butyl Acrylate Using TEMPO: Improvement of Control Exploiting Nanoreactors?

“…The details of the modeling approach used to investigate compartmentalization effects in NMP have been fully described in previous papers and will not be repeated here 18, 23, 24. In short, the modified Smith–Ewart equations describe the number fractions of particles $N_{i}^{j} $ (particles containing i P • and j T • ): where N A is the Avogardo's number and v p is the particle volume.…”

“…CLRP in dispersed systems14, 15 can under certain circumstances be strongly influenced by the phenomenon of compartmentalization, which refers to the physical isolation of reactants in discrete confined spaces, i.e., the monomer droplets or polymer particles. Effects of compartmentalization have been predicted theoretically for NMP,16–24 atom transfer radical polymerization (ATRP),22, 25–28 and reversible addition‐fragmentation chain transfer (RAFT) polymerization,21, 22, 29–32 and experimental evidence is also starting to emerge 33–36. There are two possible distinct effects of compartmentalization: The segregation effect and the confined space effect 14, 18.…”

“…The confined space effect refers to how the rate of reaction between two species is higher in a small particle than in a large particle. The confined space effect can cause the rate of deactivation to increase in CLRP systems based on the persistent radical effect (e.g., NMP and ATRP) 18–21, 23–28, 36…”

Deterministic Approaches for Simulation of Nitroxide-Mediated Radical Polymerization

“…They found that the nature of the nitroxide influenced the minimum particle size beyond which compartmentalization could not be neglected. Subsequently, Zetterlund [115] reviewed and also presented new results on compartmentalization and nitroxide partitioning effects. In this work, they implemented a model in Predici to predict the partitioning of the nitroxide between phases.…”

Progress in Computer Simulation of Bulk, Confined, and Surface‐initiated Polymerizations

“…The purpose of this review is to provide a brief account of the progress in computer simulations of polymerization reactions in confined geometries and on surfaces. Because recent reviews have dealt in depth with in silico polymerization in confined spaces,9–11 we will concentrate primarily on the class of macromolecules prepared by direct polymerization from surfaces. We will revisit briefly some aspects of the various methods that have been applied to describe polymerization reactions in bulk and point out how some of those approaches can be adopted in the so‐called “grafting from” polymerizations.…”