Structure formation in paints and coatings

General ILL seminar organised by College 9

Monday 26 October, 2026 at 14h00

Seminar room 110-111, ILL 50, 1st floor

Zoom link: https://ill.zoom.us/j/93326326401?pwd=mq7JqMLctpkqw7hIcPWTq6QGt8nGOg.1

Passcode: SeminarC9

"Structure formation in paints and coatings"

Ramón Rial^a, Isabell^a M.V. Ewell^b, Miguel No-Gómez^b, Javier Montenegro^b, A. Sánchez-Fernández^c

a. Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Departamento de Física Aplicada, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.

b. Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.

c. Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Departamento de Enxeñaría Química, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.

ramon.rial@usc.es

Deep eutectic solvents (DESs) constitute a highly tunable class of liquid media formed by the association of two or more components (e.g., a hydrogen-bond donor and an organic salt), whose extensive hydrogen bonding interactions result in a pronounced depression of the melting point. Their composition-dependent physicochemical properties make DESs particularly attractive for directing the self-assembly of functional soft materials [1,2]. In this context, eutectogels (gels formed within DES media), offer a versatile platform in which solvent–solute interactions can be exploited to modulate macroscopic material properties beyond those dictated by the gelator alone [3].

Herein, we report a versatile strategy for the design of light-responsive eutectogels with intrinsically tunable mechanical properties. The approach relies on the supramolecular co-assembly of an amphiphilic component with a rationally designed azobenzene derivative engineered for high solubility in water-free DES media. Through complementary characterization across molecular and mesoscale length scales, we provided a detailed understanding of the heterotypic interactions underlying the formation of elongated, one-dimensional supramolecular networks. We further establish that photoisomerization of the azobenzene units induces pronounced rearrangements of these networks, providing a molecular-level mechanism for controlling the material’s hierarchical organization.

Upon ultraviolet irradiation, this molecular reconfiguration leads to an abrupt gel-to-sol transition, effectively erasing the material’s solid-like mechanical response. Subsequent exposure to visible light reverses the process, restoring the gel state and recovering a mechanically robust network that remains stable during prolonged storage without appreciable loss of performance. Remarkably, the optically driven transition is highly reversible and cyclable, enabling repeated switching between gel and sol states without detectable deterioration of structural integrity or mechanical properties. Collectively, these results demonstrate how molecular photochemical events can be translated into reversible macroscopic mechanical actuation, establishing DES-based supramolecular eutectogels as promising platforms for dynamically reconfigurable soft matter.

Keywords

Deep Eutectic Solvents, Eutectogels, Photo-responsive Materials, Self-Assembly

Acknowledgements

The authors acknowledge financial support from MCIN/AEI (RYC2022-037909-I and PID2022-141673OA-I00).

References:

[1] Hansen, B. et al., Chem. Rev. 2021, 101, 1232-1285.

[2] P. A. Mercadal, A. González, A. Beloqui, L. C. Tomé, D. Mecerreyes, M. Calderón and M. L. Picchio, JACS Au, 2024, 4, 3744-3758.

[3] A. Sanchez-Fernandez, J. F. Poon, A. E. Leung, S. F. Prevost and C. Dicko, ACS Nano, 2024, 18, 18314-18326.

Orsolya Czakkel (College 9 Secretary)

External visitors may ask for a site access to tellier(at)ill.fr

College 9 Seminar | Structure formation in paints and coatings