The development of synthetic smart materials that perform on-demand tasks in complex environments, while triggered noninvasively, is a major goal to develop the next generation of soft robotics. However, fast and complex locomotion with high spatial-temporal precision using external stimuli controlling shape in such systems remains a major challenge. Here, we describe a light-responsive soft material based on liquid crystal polymer networks (LCPNs) with variable stiffness comprising highly efficient light-driven molecular rotary motors and dye molecules. This system selectively responds to light of specific wavelengths, enabling highly programmable and complex motions, such as jumping, rotating, and climbing. The rapid response of molecular motor triggered by UV-light (photochemical effect) and the heat generated by dye upon red-light irradiation (photothermal effect), can be decoupled and orthogonally controlled, due to unique features of the molecular motor. Our study shows how cooperativity and amplification of molecular motion can lead to the rapid actuation of synthetic materials, which offers novel molecular tools and materials engineering perspectives for the development of intelligent soft robotics.

Molecular motors with red-shifted absorption are highly attractive for biomedical applications, yet remain challenging to realize because conventional strategies for extending excitation wavelengths often compromise photochemical efficiency and directional motor function. Here, we report a protonation-gated strategy in which reversible modulation of conjugation topology enables state-dependent molecular motor operation across a broad visible-light window. Modifying coumarin-derived overcrowded alkenes with benzazole substituents, the resulting motors undergo efficient photoisomerization under blue-green light irradiation. Photophysical studies supported by DFT calculations reveal that protonation induces a pronounced conformational inversion with the formation of intramolecular hydrogen bonds, thereby promoting molecular planarization and enhanced electronic delocalization, leading to the efficient photoisomerization under 530-600 nm irradiation while quantitative photoconversion is retained. Overall, these findings establish reversible protonation as a powerful chemical gating strategy to expand the visible-light responsiveness of the motor without permanent structural modification, paving the way for its application in multimodal responsive bioimaging and advanced optical devices.

Abstract Liquid crystal polymer networks (LCPNs) exhibit remarkable light-responsive actuation, yet the molecular-level design rules governing their performance remain elusive. Here, we develop a series of molecular motor-based photo-responsive units with tunable rigidity, and different substituents, enabling precise modulation of LCPN mechanics and photo-responsive behavior. By systematic study and comparing these motors with conventional azobenzene and second-generation molecular motors, we establish clear structure-property relationships that link molecular design to macroscopic actuation efficiency and network stiffness. Notably, our motor-integrated LCPNs also exhibit intrinsic fluorescence, enabling shape-encoded pattern visualization without the need for additional fluorescent molecules. This multifunctional liquid crystal-motor hybrid system integrates light-induced actuation, mechanical tunability, and fluorescence signaling, offering design principles for next-generation soft actuators and intelligent photonic devices.

Switching the handedness of circularly polarized luminescence (CPL) at the molecular level remains a challenge in the development of responsive chiral materials. We report a light-driven molecular motor covalently linked to two perylenediimide (PDI) chromophores, enabling reversible and directional modulation of CPL. The different motor states, which are accessible in a unidirectional fashion via light-irradiation and thermal helix inversion steps, respectively, display significantly distinct chiroptical properties. In addition, our system allows switching of the chiral induction process and hence, the observation of a CPL signal. The present work discloses the first example of reversible CPL sign inversion triggered by light irradiation at the single molecular level, offering a new starting point for designing emitters with light-responsive chirality modulation.

Molecular motors have been operated in a myriad of environments since their inception more than two decades ago. Of particular interest are systems in which a structural frame of reference for the motor's rotary motion is established. Examples include motors adsorbed on surfaces, embedded in framework materials, used as dopants in liquid crystals, or incorporated into polymer matrices. Embedding the molecular motor as a guest in a supramolecular cage assembly, however, remains an unexplored strategy. Such systems are particularly attractive, as they would allow the motor's rotation to drive mechanical motion from within the assembly, provided the motion does not lead to the guest motor's release. Here, the first motor-nanocage host-guest system in which a thermal and light-driven full 360° unidirectional rotational cycle occurs within the confined space of the nanocage is reported. We identified key structural elements that enable the formation of a host-molecular motor complex with unprecedented stability, governed by a noncovalent interaction between the motor's alkyl-COOH moiety and a carbonyl residue on the cage. This strategy allows the formation of stable host-guest complexes without relying on a size-induced fit, as is commonly observed in other inclusion complexes. This enables rotation to occur within the cage cavity despite dramatic geometric changes. We envision this strategy as a valuable tool for developing a new generation of molecular motors operating in confined spaces.

Artificial molecular motors convert light into rotary motion and are central components of synthetic molecular machineries. Their rotation frequency is key to their performance and is typically rationalized in terms of intrinsic molecular structure and solvent viscosity, while the influence of supramolecular organization remains largely unexplored. Here, we show that motor rotation is governed not only by viscosity but also by the supramolecular organisation of the surrounding medium. Thermodynamic analysis reveals that, beyond the viscosity-related increase observed in the isotropic phase of the same host, nematic order introduces an additional enthalpic penalty of 10-14 kJ mol-1 for the rate-determining thermal helix inversion. The magnitude of this penalty follows the alignment of the metastable cis-states involved in helix inversion, consistent with an order-dependent elastic resistance. These findings identify supramolecular order as a kinetic control parameter for artificial molecular motors and reveal reciprocal coupling between molecular-machine operation and soft-matter organization.

Developing responsive coatings and materials requires discovering a breadth of mechanisms by which external stimuli can be converted into useful signals. Here, we demonstrate an approach driven by supramolecular mechanochemistry, where mechanical input-molecular shape change-is translated into structural color variation. By embedding bistable, negatively photochromic hydrazone photoswitches into cholesteric polymer networks, we achieve a reversible, stable color shift through molecular-scale pulling and pushing of the photonic scaffold. Unlike azobenzene-based systems, which typically disrupt liquid crystal order, this approach modifies the pitch of a cross-linked cholesteric helix without disrupting the organisation of the material. The long-lived stability of both hydrazone isomers ensures durable optical switching. This effect provides a new strategy for designing mechanoresponsive photonic coatings and tunable optical materials.

Stimuli-responsive materials based on molecular switches, introducing life-like properties such as adaptive behavior in an aqueous environment, are fascinating, providing numerous opportunities to control functions and enable future applications like actuators and soft robotics. Light-responsive molecular systems are receiving particular attention, due to the non-invasive stimulus and distinctive spatio-temporal control possible with photoswitches. In contrast, redox-switching is quantitative, non-volatile and associated with significant changes in material properties, but lacks spatio-temporal precision. Herein we address this challenge in the first proof-of-principle demonstration of light-gated redox switching of polymer hydrogel materials, thereby combining the advantages of both strategies. We present a unique approach where irradiation controls the intrinsic redox properties of the system. This is enabled by the reversible and versatile light- and redox-responsive bisthioxanthylidene switch embedded in a polymer hydrogel, whose two-electron oxidation potential is strongly modulated by light. As a result, oxidation of the material, which is associated with large changes in color, fluorescence, swelling and actuation can be carried out in water with high precision in space and time by photo-masking. This light-gated redox-patterning of the material can be exploited for numerous functions including, as demonstrated here, complex motion and reversible surface texturing.

The integration of light-driven molecular machines with lipid membranes holds significant interest for advancing biological applications, necessitating a comprehensive understanding of the underlying biophysical mechanisms. Here, we report the incorporation of nine alkene-based molecular rotary motors with diverse chemical compositions into synthetic lipid membranes and establish a set of experimental tools to probe their behavior. Through molecular-scale characterizations, including motor positioning, orientation, aggregation, and uptake efficiency, as well as analysis of rotation cycle dynamics under membrane confinement, we elucidate the complex interactions between these molecular machines and lipid membranes. Moreover, we investigate the influence of motor incorporation on the biophysical properties of the membrane, such as fluidity and membrane tension. Additionally, we examine light-triggered membrane deformations and area expansion using the electrodeformation of giant vesicles. Our findings reveal significant differences in how molecular rotary motors interact with membranes, providing a comprehensive framework for future applications of synthetic molecular machines in biological contexts.

Endowing liquid crystal (LC) soft matter with stimuli-responsiveness is pivotal for programmable and dynamic photonics in the next generation of optical materials. However, suitable molecular candidates with intrinsic dynamic chirality that can twist LC helices using external stimuli in a multistate, distinct manner are still very rare. In this study, an elaborately designed intrinsically chiral molecular machine is presented with four-state dynamic chirality and mesogenic units. This design enables direct chirality transmission, leading to sequential quadruple helix inversions of the LC architecture via unidirectional rotary motion, achieving a high helical twisting power in all states. The inversion of the supramolecular helicity by near-infrared (NIR) light is demonstrated by NIR light-triggered isomerization of the molecular motor structure through an efficient radiative energy transfer pathway from upconversion nanoparticles in the LC film. Hence, these results demonstrate a unique photoresponsive LC system with high robustness, NIR light triggering, and multistate helix tunability with a fascinating potential for constructing smart optical devices.

The reversible modulation of chirality has gained significant attention not only for fundamental stereochemical studies but also for numerous applications ranging from liquid crystals (LCs) to molecular motors and machines. This requires the construction of switchable molecules with (multiple) chiral elements in a highly enantioselective manner, which is often a significant synthetic challenge. Here, we show that the dimerization of an easily accessible enantiopure planar chiral ferrocene‐indanone building block affords a multi‐stimuli‐responsive dimer (FcD) with pre‐determined double bond geometry, helical chirality, and relative orientation of the two ferrocene motifs in high yield. This intrinsically planar chiral switch can not only undergo thermal or photochemical E/Z isomerization but can also be reversibly and quantitatively oxidized to both a monocationic and a dicationic state which is associated with significant changes in its (chir)optical properties. Specifically, FcD acts as a chiral dopant for cholesteric LCs with a helical twisting power (HTP) of 13 µm−1 which, upon oxidation, drops to near zero, resulting in an unprecedently large redox‐tuning of the LC reflection color by up to 84 nm. Due to the straightforward stereoselective synthesis, FcD, and related chiral switches, are envisioned to be powerful building blocks for multi‐stimuli‐responsive molecular machines and in LC‐based materials.

Artificial molecular motors and machines constitute a critical element in the transition from individual molecular motion to the creation of collective dynamic molecular systems and responsive materials. The design of artificial light-driven molecular motors operating with high efficiency and selectivity constitutes an ongoing fundamental challenge. Here we present a highly versatile synthetic approach based on Rieche formylation that boosts the quantum yield of the forward photoisomerization reaction while reaching near-perfect selectivity in the steps involved in the unidirectional rotary cycle and drastically reducing competing photoreactions. This motor is readily accessible in its enantiopure form and operates with nearly quantitative photoconversions. It can easily be functionalized further and outperforms its direct predecessor as a reconfigurable chiral dopant in cholesteric liquid crystal materials. Overcrowded alkene-derived molecular motors convert light and heat into chirality-directed unidirectional rotary motion, but the efficiency of their photochemical isomerization remains limited. Now formylation of the motor core has been shown to boost all aspects of motor photochemistry by improving photochemical efficiency, diminishing competing processes and redshifting absorption.

The transmission of chiral information between the molecular, meso and microscopic scales is a facet of biology that remains challenging to understand mechanistically and to mimic with artificial systems. Here we demonstrate that the dynamic change in the expression of the chirality of a rotaxane can be transduced into a change in pitch of a soft matter system. Shuttling the position of the macrocycle from far-away-from to close-to a point-chiral center on the rotaxane axle changes the expression of the chiral information that is transmitted across length scales; from nanometer scale constitutional chirality that affects the conformation of the macrocycle, to the centimeter scale chirality of the liquid crystal phase, significantly changing the pitch length of the chiral nematic structure.

Photonics and tunable optics are rapidly developing fields that require materials with programmable properties and advanced functionalities. Cholesteric liquid crystals (CLCs) are unique materials that exhibit selective light reflection and can be tuned using stimuli-responsive small organic molecules. The challenge lies in designing molecules that can convert external signals, such as light, into dynamic and invertible chiral states, which can be transduced to the CLC supramolecular structures inducing large differences in helicity and eventually to macroscopic properties. Here, novel intrinsically chiral phenanthrene-based diarylethenes as light-responsive chiral dopants for controlling the supramolecular helical architectures of CLCs are introduced. The substitution pattern and light-invertible axial chirality of these diarylethenes make them highly compatible with liquid crystals and provide high twisting power. The light-induced cyclization and molecular chirality transformation result in a wide tunability of the cholesteric helix pitch (reflection colors) and reversible inversion of helical handedness. These findings provide a powerful tool for controlling and manipulating the macroscopic properties of CLCs, opening new avenues for a range of applications, including diffractive optics and photonics, anticounterfeiting tags, and displays. The inherent dynamic chirality of phenanthrene-based diarylethenes is effectively transferred from a molecular level to a supramolecular level, resulting in a microscopic helical structure. The compatibility between the designed molecular switches and liquid crystals has enabled the photonic material with various fascinating properties, including rapid responsivity, substantial helicity modulation, and light-induced helix inversion.image

The ability to relay mechanical effects and information from the nanoscale to larger-length scales has potential for the development of responsive and adaptive materials. Here, we describe how the light-mediated translocation of a macrocycle between different sites on a rotaxane axle, a dynamic process that switches shape at the nanoscale, can be used for generating directional microscopic transport. The effect results from the change in the expression of rotaxane chirality experienced by a liquid-crystal medium. The position of the macrocycle within the rotaxane determines not only the pitch of the liquid-crystal helix but also its handedness. The helix inversion sets topological defects in motion, and these cause macroscopic spiral rotation of the microparticles confined within the defects. The process can be used for collecting and cleaning a surface of microparticles and dust particles. The results illustrate how mechano-stereochemical changes can be transduced across length scales into directional transport.

Synthetic materials can change shape in response to stimuli, with mechanisms reported so far based on the induction of disorder in a pre-organized molecular system. By contrast, harnessing molecu-lar motion by transducing the work of molecular machines is ener-getically more effective and can mediate functional complexity, as exemplified in biological systems. Here, we show that the power strokes operated by a light-driven molecular motor at the nanoscale can be transduced into the repeated back-and-forth swaying motion of a polymer at the macroscopic length scale. The synchronization of molecular motors, as governed by the energetic landscape of the rotary cycle, is essential to this transduction. Combining syn-chronization in time with orientation in space allows transducing one molecular rotation into one macroscopic swaying motion using a mechanism that shows analogy with reciprocating pumps. Making materials operate through a variety of sophisticated transduction modes will be critical for the field of autonomous soft robots.

Future robotic systems will have to adapt their operation to dynamic environments and therefore their development will require the use of active soft components. Bioinspired approaches toward novel actuation materials for active components rely on integrating molecular machines in soft matter, and ensuring that their nanoscale movement is amplified to the macroscale, where mechanically relevant motion is generated. This approach is successfully used in the design of photoresponsive soft springs and other mechanically active materials. Here, this study reports on a new approach where the operation of photoswitches and chiral liquid crystals are combined with an original and mask-free microscopic patterning method to generate helix-based movement at the macroscale, including light-driven winding and unwinding accompanied with inversion of handedness. The microscopic patterning is the result of the unique organization of cholesteric liquid crystals under weak electric field. At a higher level, the pitch and the handedness of the active springs are defined by the imprinted pattern and the angle at which the spring ribbons are cut in the material. These findings are likely to enable soft and responsive robotic systems, and they show how transmission of molecular operation into macroscale functional movement is enabled by materials design across multiple hierarchical levels.

Microscopic motility is a property that emerges from systems of interacting molecules. Unraveling the mechanisms underlying such motion requires coupling the chemistry of molecules with physical processes that operate at larger length scales. Here, we show that photoactive micelles composed of molecular switches gate the autonomous motion of oil droplets in water. These micelles switch from large trans-micelles to smaller cis-micelles in response to light, and only the trans-micelles are effective fuel for the motion. Ultimately, it is this light that controls the movement of the droplets via the photochemistry of the molecules composing the micelles used as fuel. Notably, the droplets evolve positive photokinetic movement, and in patchy light environments, they preferentially move toward peripheral areas as a result of the difference in illumination conditions at the periphery. Our findings demonstrate that engineering the interplay between molecular photo-chemistry and microscopic motility allows designing motile systems rationally.

Motility is the capacity for living organisms to move autonomously and with purpose, and is essential to life. The transition from abiotic chemistry into motile cellular compartments has yet to be understood, but motile behaviour likely followed chemical evolution because primeval cell survival depended on scouting for resources effectively. Minimalistic motile systems provide an experimental framework to delineate the emergence mechanisms of such an evolutionary asset. In this Review, we discuss frontier developments in controlling the movement of droplets in lipid systems, in particular, chemotactic behaviours driven by fluctuations in interfacial tension, because of its simple mechanism and prebiotic relevance. Although most efforts have focused on designing oil droplet motility in lipid-rich aqueous solutions, we highlight that water droplets can also move in lipid-enriched oils. First, we describe how droplets evolve chemotactic motility in lipid systems. Next, we review how these oil droplets can adapt their movement to illumination conditions. Finally, we discuss examples where chemical reactivity brings complexity to motility. This work contributes to systems chemistry, where chemical reactions combined with physicochemical phenomena can yield new functions, such that a limited set of molecules can promote complex movement at larger functional scales by following the rules of molecular chemistry.