Understanding the mechanisms by which fluids generate and transmit mechanical forces is fundamental to both biological systems and the design of responsive soft materials. However, owing to their inherent lack of positional order, fluids typically struggle to generate forces beyond the piconewton scale, limiting their ability to deform and reshape their surroundings. Here, we introduce a class of structured fluids that integrate liquid-crystalline and ferroelectric orders, enabling exceptionally sensitive and large-amplitude electromechanical transduction that is unattainable with traditional fluids. The ferroelectric lamellar order enhances local topological forces, reaching levels exceeding micronewtons, which is three orders of magnitude greater than those observed in non-lamellar fluids. This discovery establishes a physical principle of liquid-matter mechanics that links topology and deformation, paving the way for approaches to in-situ manipulation and shape control of micro-objects embedded in fluids. Fluids lack positional order, which limits their ability to reshape objects and function as soft mechanical materials. Here, the authors show that a ferroelectric smectic-A liquid crystal can exert micronewton-scale forces and rotate and reshape embedded soft inclusions much more strongly than non-lamellar fluids.
Zou et al. (Sat,) studied this question.