Helical Out-of-Equilibrium Systems: Exploring Light-Induced Structural Distortions

Helical architectures are prevalent in natural and artificial settings due to their mechanical robustness, chiroptical properties, and ability to assemble compactly through intra- and intermolecular interactions. We propose that reversible distortions to these structures can unlock new behaviors. Inspired by recent advancements in supramolecular chemistry and light-responsive molecules, we aim to couple light-responsive units (LRUs) to helical structures to drive them out-of-equilibrium (OOE), thereby modulating their functionality and achieving photoactuation. Adopting organic and metal-organic spring-like model systems, we aim to achieve compression, extension, and complete unwinding of the helices under photoirradiation. In the OOE state, we hypothesize that the systems can store and release energy, making them promising candidates for optomechanical work and offering an alternative design strategy for molecular solar-thermal (MOST) materials. Furthermore, our approach enables the precise placement of LRUs within the helical structure, which is anticipated to provide customized optomechanical responses, such as bending and twisting, and allow new light-gated reactivity and feedback loops. Expanding this concept, we will explore larger, polymeric versions of these materials in bulk, such as films and fibers, to achieve light-powered translation, rotation, and lifting of objects. This fundamental study establishes a new research area focused on using LRUs to perturb discrete helical structures OOE, advancing the current approaches to perform mechanical work on the macroscopic level and presenting a novel design approach for MOST materials. Success will undoubtedly catalyze interest in exploring other helical architectures beyond the model systems studied here, achieving photoactuators of greater complexity in their operation and function.