How Dispersity from Step-Growth Polymerization Affects Polymer Dynamics from Coarse-Grained Molecular Simulations

Abstract

While step-growth synthetic polymers are among the most highly utilized polymeric materials, the negative environmental impact of these materials has become an urgent issue, due largely to their accumulation in the natural environment and the lack of sufficient and effective recycling options. Recently, reversible addition-fragmentation chain transfer (RAFT) step-growth polymerization has been developed, which allows these materials engineered to be more biodegradable. In light of the emerging importance of this novel method of polymer synthesis, we employ coarse-grained molecular dynamics simulations to better understand how the step-growth polymerization process affects the equilibrium dynamical properties of this class of polymer materials. More specifically, we consider how the dispersity of molecular mass inherent to step-growth polymerization affects the diffusion coefficient, glass transition, fragility, and both the segmental and heterogeneous dynamics of these materials. We link these trends to the wide distribution of chain lengths, as well as the overall large average degree of polymerization.

Solid-State, Single-Ion Conducting, Polymer Blend Electrolytes with Enhanced Li+ Conduction, Electrochemical Stability, and Limiting Current Density

“…The nonmonotonic trend of conductivity vs M n,PLiMTFSI implies that molecular weight is not the sole contributor to the polymer packing frustration. Apart from the molecular weight, , there are other factors impacting the efficiency of polymer chain packing space and the corresponding free volume, such as the dispersity, the backbone rigidity, , the “relative” rigidity of the side group(s) vs the backbone, the molecule symmetry, end-group chemistry, , and inter/intra-molecular interactions. − These factors are typically cross-correlated in polymer systems, and a detailed deconvolution is beyond the scope of this work.…”

Full‐scale modeling of chemical experiments

“…Zhang et al. used the above model to study how the dispersity of molecular mass affects the diffusion coefficient, glass transition, and fragility of polymers prepared by reversible addition‐fragmentation chain transfer (RAFT) polymerization [32] . MC is also an efficient method to study the polymerization reaction process.…”

“…Zhang et al used the above model to study how the dispersity of molecular mass affects the diffusion coefficient, glass transition, and fragility of polymers prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. [32] MC is also an efficient method to study the polymerization reaction process. Nagaoka et al used a hybrid Monte Carlo/molecular dynamics method, the Red Moon (RM) method, to study the 1-octene polymerization reaction catalyzed by the ionic pair at different monomer concentrations, where the degree of polymerization was consistent with experimental results.…”