Phase separation and aggregation in multiblock chains

This paper focuses on phase and aggregation behavior for linear chains composed of blocks of hydrophilic and hydrophobic segments. Phase and conformational transitions of patterned chains are relevant for understanding liquid-liquid separation of biomolecular condensates, which play a prominent role in cellular biophysics and for surfactant and polymer applications. Previous studies of simple models for multiblock chains have shown that, depending on the sequence pattern and chain length, such systems can fall into one of two categories: displaying either phase separation or aggregation into finite-size clusters. The key new result of this paper is that both formation of finite-size aggregates and phase separation can be observed for certain chain architectures at appropriate conditions of temperature and concentration. For such systems, a bulk dense liquid condenses from a dilute phase that already contains multi-chain finite-size aggregates. The computational approach used in this study involves several distinct steps using histogram-reweighting grand canonical Monte Carlo simulations, which are described in some level of detail.

Automated summary

This paper investigates the phase and aggregation behavior of linear chains composed of hydrophilic and hydrophobic blocks. The phase and conformational transitions of patterned chains are important for understanding liquid-liquid separation of biomolecular condensates and have applications in cellular biophysics, surfactants, and polymers. The key finding of this study is that certain chain architectures can exhibit both finite-size aggregate formation and phase separation under appropriate conditions of temperature and concentration. The computational approach used in this study involves histogram-reweighting grand canonical Monte Carlo simulations, which are described in detail.