Computational reverse-engineering analysis for scattering experiments (CREASE) on thermoresponsive assembly of methylcellulose in aqueous solutions

Past studies have shown that methylcellulose (MC) assembles into fibrils in aqueous solutions, with consistent average fibril diameters with varying MC molecular weight and concentration. However, the molecular mechanism of the assembly and the packing of individual MC chains within the fibrils remain unclear. In this study, we use a newly developed coarse-grained model of MC and molecular dynamics simulations to understand the molecular mechanism of assembly and MC chain packing in the fibrils. Taking small angle X-ray scattering (SAXS) profiles for MC solutions obtained experimentally by Bates, Lodge and coworkers [Macromolecules, 2018, 51, 7767-7775] as input to our recently developed machine learning enhanced computational reverse engineering method for scattering analysis (CREASE) [ACS Polymers Au, doi.org/10.1021/acspolymersau.1c00015] we determine the fibrils’ dimensions (length, diameter, flexibility, dispersity) and chain packing within the fibrils. Our computational work provides insight into the intriguing self-assembly of MC into fibrils and gels, and generally, fibrillar network formation in solutions of semiflexible polymers.