Abstract
We use coarse-grained molecular dynamics simulations to study the precursor steps for fibril formation in methylcellulose solutions. Simulations of ring stacking between two collapsed methylcellulose chains demonstrate the existence of a capture radius that is much larger than that predicted by polymer diffusion alone. When two rings are in very close proximity, they stack together to form a fibril precursor. Simulations of stacks of such rings suggest that this structure is metastable. In contrast, chains that are within the capture radius but not in close proximity, as well as for systems containing both ringlike and relaxed chains, fibril-like structures form via a distinctly different mechanism. Irrespective of their initial arrangement, the chains undergo two specific conformational changes: (i) a part of either a ring or a randomly coiled chain splays out and (ii) the splayed chain subsequently engulfs a nearby chain if it is within a certain capture distance. The latter results are consistent with recent experimental measurements of fibril formation by short methylcellulose chains, which suggests the formation of a twisted bundle.
| Original language | English |
|---|---|
| Article number | 055601 |
| Journal | Physical Review Materials |
| Volume | 3 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 1 2019 |
| Externally published | Yes |
Funding
V.S. acknowledges fruitful discussions with Dr. Xiaolan Li during the initial stages of this work. This work was supported primarily by the National Science Foundation through the University of Minnesota Materials Science Research and Engineering Center under Award No. DMR-1420013. The authors acknowledge the Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing resources that contributed to the research results reported within this paper.