A research group led by Nagoya Institute of Technology in Japan have developed a new supramolecular polymer system that produces out-of-equilibrium states with different dimensionalities. This pioneering study was headed by Professor Shiki Yagai from Chiba University. It demonstrates that the brightness of light used on a system dictates whether these structures are created. This research was initially published online in the journal Chem on November 17, 2025.
As a first goal of the study, we aimed to create molecular assemblies that run against thermodynamic equilibrium. To achieve this, the researchers incorporated a light-responsive unit into a molecule known for its ability to exhibit varying assembly structures under different conditions. Through careful control of the light intensity, they were able to precisely drive the highly dynamic molecule into well-defined structures.
At first, the molecule spontaneously organized itself into 1D coiled nanofibers. Upon exposure to ambient light conditions, these nanofibers undergo a fascinating photochemical reaction whereby they convert to thermodynamically stable two-dimensional (2D) nanosheets. The switch only occurred because the hydrogen bonds had been rearranged. It proceeded according to an Ostwald ripening mechanism, further illustrating the complex and dynamic nature of the system.
High-speed atomic force microscopy (HS-AFM) was essential in recording these localized transformation events. It is very good at predicting things like secondary nucleation or epitaxial growth. Having the ability to visualize these processes really enhances our understanding of how light impacts molecular assembly on a fundamental level.
“This out-of-equilibrium supramolecular system paves the way for developing highly functional materials that can alter their states in response to external stimuli, much like living systems.” – Professor Shiki Yagai
The results from this study hold promise for developing materials that can self-tune to shifts in surroundings. Professor Yagai elaborated on the future implications of their work, stating, “Looking ahead, by incorporating photoactive, electroactive, or even catalytic functions directly into the molecular design, it may be possible to create systems whose functional performance spontaneously adapts to environmental changes.”
Professor Yagai emphasized the significance of their research approach, remarking, “Our group has long been pursuing unique research aimed at controlling the nano- to mesoscale morphologies of molecular assemblies using light.” He further noted the novelty of their findings, stating, “We had not yet realized an out-of-equilibrium system that, much like living organisms, changes its structure or state depending on the amount of energy it receives.”
