How the 3D Shape of Rigid Filaments Determines Material Mechanics in Water: Study.

The mechanics and dynamics of polymer materials are highly influenced by their geometry and topology. However, little is known about the effect of three-dimensional shape on the microscopic dynamics and macroscopic rheological characteristics of suspensions of rigid filaments. An international team of physicists has conducted a study to examine these dynamics and to understand how control of shape can be used to engineer solid-like behavior even when the suspension is more than 99% water. By studying the properties of the flagella of bacteria, the team was able to generate chimeric filaments composed of a segment of straight flagella fused to a helical one. These filaments exhibit Brownian motion when suspended in water but dramatic changes can occur after adding them to the suspension. The team found that the chimera filaments generate a glass-like solid, whereas the straight and helical filament suspensions act like viscous liquids. The study demonstrates that shape can be used to control dynamics and mechanics, opening up avenues for engineering adaptive materials with novel properties. The research has prompted exciting possibilities for the development of dynamically shape-changing metamaterials, which could switch between fluid and solid states by a chemical, optical, or electrical trigger in applications such as robotics, protective devices, and equipment and restructuring fabrics.