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The existence of a crumpled Flory phase for equilibrated self-avoiding elastic surfaces has remained contentious. Here, we show that a crumpled phase develops reliably upon subjecting a thin spherical self-avoiding shell to active fluctuations. 

Using theory and simulations, we have investigated the phonons and their role in thermal energy transport in semicrystalline polyethylenes. Considering alternating stacks of lamellae and amorphous regions, and labeling one polyethylene chain interwoven among two amorphous regions and one lamella, we have explored the underlying mechanism of thermal conductivity of polyethylene in its semicrystalline state. We report that hairpin-like folds at the crystalline–amorphous interface significantly scatter phonons, allowing only less than half of the phonons to transmit through polyethylene backbone. Monitoring the phonon propagation and scattering at the interfaces, we have computed thermal conductivity of semicrystalline polyethylene. We have derived a design principle to control thermal conductivity of semicrystalline polyethylene in terms of lamellar thickness and the number of folds per chain at the crystalline–amorphous interface. 

We have investigated the structural evolution in solutions of the intrinsically disordered protein, α-synuclein, as a function of protein concentration and added salt concentration. Accounting for electrostatic and excluded volume interactions based on the protein sequence, our Langevin dynamics simulations reveal that α-synuclein molecules assemble into aggregates and percolated structures with a spontaneous selection of a dominant structure characteristic of microphase separation. This microphase assembly is mainly driven by electrostatic interactions between the residues in N-terminal and C-terminal of the protein molecules, and presence of salt loosens the compactness of the microstructures. We have quantified the features of the spontaneously formed microstructures using interchain radial distribution functions, and experimentally measurable inter-residue contact maps and static structure factors. Our results are in contrast to the commonly hypothesized mechanism of liquid–liquid phase separation (LLPS) for the formation of droplets in solutions of intrinsically disordered proteins, opening a new paradigm to understand the birth and structure of membraneless organelles. In general, construction of phase diagrams of intrinsically disordered proteins and other biomacromolecular systems needs to incorporate features of microphase separation into other mechanisms of macrophase separation and percolation.