Confessions of a Gel Whisperer: insight into Electron-responsive Self-Assembly of a Supramolecular Gel and the early stage of Cheese making

In this seminar I will discuss a redox-active supramolecular gel formed through the chiral self-assembly of a low-molecular-weight viologen (4,4'-bipyridinium) derivative. These gels, made from small organic molecules, show promise for applications in catalysis and electronics.

Part 1 – In this seminar I will discuss a redox-active supramolecular gel formed through the chiral self-assembly of a low-molecular-weight viologen (4,4'-bipyridinium) derivative. These gels, made from small organic molecules, show promise for applications in catalysis and electronics. Unlike most existing systems that depend on chemical fuels and thus have limited reversibility, this work demonstrates reversible electron-responsiveness using electrochemical and photochemical stimulation. The reduction of viologen units within the gel triggers structural changes linked to the formation and dissociation of charge-transfer complexes, as confirmed by in operando microscopy and absorption spectroscopy. Notably, the gel network can dissolve and reform reversibly under electrochemical control, marking one of the first examples of a system capable of reversible, electrochemically induced supramolecular polymerization [1-5]. Part 2— I will then explore the early stages of cheese making from a soft matter perspective, focusing on the enzymatic gelation and aging of casein micelles, which behave as soft, attractive colloids. Using time-resolved rheology combined with scattering (SAXS, XPCS) and imaging techniques, we identify two distinct stages of gel aging: the rapid formation of a particulate network at gelation, followed by microstructural consolidation through evolving interparticle contacts [6-13]. These findings deepen our fundamental understanding of how soft colloidal gels form, age, and yield.