Phase behaviour and self-assembly of semiflexible polymers in poor-solvent solutions
arXiv:2405.11287 · doi:10.1021/acs.macromol.4c01111
Abstract
Using Langevin dynamics complemented by Wang-Landau Monte Carlo simulations, we study the phase behavior of single and multiple semiflexible polymer chains in solution under poor-solvent conditions. In the case of a single chain, we obtain the full phase diagram in the temperature-bending rigidity (stiffness) plane and we provide connections with a classical mean field result on a lattice as well as with past results on the same model. At low bending rigidity and upon cooling, we find a second order coil-globule transition, followed by a subsequent first order globule-crystal transition at lower temperatures. The obtained crystals have the shape of a twisted rod whose length increases with the increase of the stiffness of the chain. Above a critical value of the stiffness, we also find a direct first order globule-crystal transition, with the crystal having the form of a twisted toroid. Close to the triple point, we find a region with isoenergetic structures with frequent switching from rods to toroids, with the toroid eventually becoming the only observed stable phase at higher stiffness. The model is then extended to many thermally equilibrated chains in a box and the analogous phase diagram is deduced where the chains are observed to first fold into a globule bundle at low stiffness upon cooling, and then rearrange into a nematic bundle via a nucleation process involving an isotropic-nematic transition. As in the single chain counterpart, above a critical stiffness the chains are observed to undergo a direct transition from a gas of isotropically distributed chains to a nematic bundle as the temperature decreases in agreement with recent suggestions from mean field theory. The consequences of these findings for self-assembly of biopolymers in solutions are discussed.
59 pages, supporting information; published in Macromolecules (2024)
References in corpus (29)
- An efficient, multiple range random walk algorithm to calculate the density of states
- Equilibration of Long Chain Polymer Melts in Computer Simulations
- Spinodal-assisted crystallization in polymer melts
- Phase diagram of Janus Particles
- Geometry and symmetry presculpt the free-energy landscape of proteins
- A numerical study of one-patch colloidal particles: from square-well to Janus
- Phase Transitions of Single Semi-stiff Polymer Chains
- The effect of chain stiffness on the phase behaviour of isolated homopolymers
- Phase diagram of a semiflexible polymer chain in a solvent: application to protein folding
- Self-Templated Nucleation in Peptide and Protein aggregation
- Collapse of a semiflexible polymer in poor solvent
- Knots as Topological Order Parameter For Semi-Flexible Polymers
- From toroidal to rod-like condensates of semiflexible polymers
- Bethe Approximation for a Semi-flexible Polymer Chain
- Effective stiffness and formation of secondary structures in a protein-like model
- Spontaneous Domain Formation in Spherically-Confined Elastic Filaments
- Knots are Generic Stable Phases in Semiflexible Polymers
- Chain stiffness bridges conventional polymer and bio-molecular phases}
- Local symmetry determines the phases of linear chains: a simple model for the self-assembly of peptide
- Phase diagram of the ground states of DNA condensates
- Impact of bending stiffness on ground-state conformations for semiflexible polymers
- Stable intermediate phase of secondary structures for semiflexible polymers
- Protein solutions close to liquid-liquid phase separation exhibit a universal osmotic equation of state and dynamical behavior
- Spontaneous dimensional reduction and novel ground state degeneracy in a simple chain model
- Phase behaviour of semiflexible lattice polymers in poor-solvent solution: mean-field theory and Monte Carlo simulations
- Low energy states of a semiflexible polymer chain with attraction and the whip-toroid transitions
- Marginally compact phase and ordered ground states in a model polymer with side spheres
- Secondary-Structure Phase Formation for Semifelxible Polymers by Bifurcation in Hyperphase Space
- Energetic preference and topological constraint effects on the formation of DNA twisted toroidal bundles