2026-02-25 ニューヨーク大学（NYU）
＜関連情報＞
- https://www.nyu.edu/about/news-publications/news/2026/february/shine-a-light–build-a-crystal.html
- https://www.cell.com/chem/abstract/S2451-9294(25)00508-X
光制御コロイド結晶化 Light-controlled colloidal crystallization
Steven van Kesteren ∙ Nicole Smina ∙ Shihao Zang ∙ Cheuk Wai Leung ∙ Glen M. Hocky ∙ Stefano Sacanna
Chem Published:February 25, 2026
DOI:https://doi.org/10.1016/j.chempr.2025.102917
Graphical abstract
The bigger picture
Colloidal systems are ideal testbeds for understanding self-assembly, yet precise control over crystallization in space and time remains elusive. We introduce a light-responsive mechanism that dynamically modulates colloidal interactions to enable spatial and temporal light patterns to direct self-assembly. Photoacids that reversibly adsorb to particle surfaces enable controlled transitions among disordered, gelled, and crystalline states without altering the global solution conditions. In the short term, these findings provide new insights into the dynamics of phase transitions in soft matter, specifically the role of amorphous intermediate states between stable suspension and equilibrium-energy crystals. In the long term, this approach lays the groundwork for reconfigurable colloidal materials that bridge the gap between passive self-assembly and active material design. These adaptable materials with dynamic, tunable photonic, electronic, or mechanical properties could be used in the next generation of computation, energy, and technologies.
Highlights
•Spiropyran photoacid renders surface charges of colloids reversibly light responsive
•Control of surface charge allows finely tuned self-assembly of colloidal crystals
•Dynamic, light-induced phase transitions between gas, gel, and crystal are studied
•Spatial and temporal patterned light controls crystal positions, shapes, and sizes
Summary
We present a light-responsive strategy for reversibly modulating Coulombic interactions between colloidal particles by leveraging a photoacid that alters particle surface charge upon illumination. This control arises from the reversible physisorption of photoacid dissociation products onto colloid surfaces, enabling dynamic tuning of interparticle forces without altering particle composition or bulk solution chemistry. Using this approach, we achieve spatially and temporally resolved crystallization via both depletion and electrostatic interactions. Real-time confocal microscopy reveals both classical and non-classical crystallization pathways, and coarse-grained molecular dynamics simulations closely recapitulate the observed behavior, providing mechanistic insight. Finally, we demonstrate programmable control over crystal formation and morphology—including localized assembly, light-guided crystal sculpting, and cyclic annealing—to fabricate larger, more ordered colloidal structures.
