(735g) Coarse-Grained Simulations to Understand the Mechanisms Underlying Ring Formation in Methylcellulose

Methylcellulose (MC) is a biopolymer obtained from cellulose and is widely used in food and drug industries. Aqueous MC solutions undergo LCST behavior and are shown to form stable hydrogels at high temperatures. Recent experiments on dilute aqueous MC solution show a clear fibrillar morphology upon heating. However, the physics of the origins of such formation is poorly understood. To this end, in this work, we perform coarse-grained molecular dynamics simulations to understand the mechanisms involved in the fibril formation of methylcellulose. Explicitly, we look at the different precursor steps that are involved in the MC fibrillar formation. We present results for a system containing mixture of ring-shaped MC and flexible chains, in different initial arrangements. We find, that irrespective of the initial arrangement, the chains undergo two specific conformational changes: (i) wherein a part of either the ring or the flexible chains undergo a ”splaying” conformation wherein part of the chain splays out to find the presence of other chains; and (ii) the ”splayed-out” chain engulfs the nearby chain if they are within a certain distance. We quantify such mechanisms by monitoring the peaks in the time evolution of the shape anisotropy factor. Together, our results show the detailed precursor mechanisms for the fibril formation of MC.