2 research outputs found
Copolymerization on Selective Substrates: Experimental Test and Computer Simulations
We
explore the influence of a selective substrate on the composition
and sequence statistics during the free radical copolymerization.
In particular, we study the radical copolymerization of styrene and
acrylic acid in bulk and in silica pores of different sizes. We show
that the substrate affects both polymer composition and sequence statistics.
We use dissipative particle dynamics simulations to study the polymerization
process in detail, trying to pinpoint the parameters responsible for
the observed differences in the polymer chain composition and sequences.
The magnitude of the observed effect depends on the fraction of adsorbed
monomer units, which cannot be described in the framework of the copolymerization
theories based on the terminal unit model
Charge Transfer Kinetics of Redox-Active Microgels
Polymer
microgel particles decorated with redox-active functional
groups are a new and promising object for electrochemical applications.
However, the process of charge exchange between an electrode and a
microgel particle carrying numerous redox-active centers differs fundamentally
from charge exchange involving only molecular species. A single act
of contact between the microgel and the electrode surface may not
be enough to fully discharge the microgel, and partial charge states
are to be expected. Understanding the specifics of this process is
crucial for the correct analysis of the data obtained from electrochemical
experiments with redox-active microgel solutions. In this study, we
employed coarse-grained molecular dynamics to investigate in detail
the act of charge transfer from a microgel particle to a flat electrode.
The simulations take into account both the mobility of functional
groups carrying the charge, which depend on the microgel architecture
and the charge exchange between the groups, which can accelerate the
propagation of charge within the microgel volume. A set of different
microgel systems were simulated in order to reveal the impact of their
characteristics: fraction of redox-active groups, microgel molecular
mass, cross-linker content, cross-linking topology, and solvent quality.
We have found trends in microgel composition leading to the most efficient
charge transfer kinetics. The obtained results would be useful for
understanding experimental results and for optimizing the design of
redox-active microgel particles aimed at faster discharge rates