Mechanochemistry: an advantageous necessity?

For more than a century, chemistry has lived under a quiet agreement: that reactions prefer to take place in solution. We dissolve. We dilute. We stir. We heat. The solvent became so familiar that it faded into the background, almost invisible, like the air in which thoughts are formed. Chemistry learned to think in terms of molecules drifting in homogeneous space, and when things did not work, the instinct was to adjust conditions rather than question the medium itself.

This way of thinking has been extraordinarily successful, but it was shaped for a very specific kind of matter: small, well-behaved molecules, suspended in liquid order. Today, chemistry increasingly meets another kind of world, one that does not dissolve so easily.

Polymers, composites, multilayer materials, thermosets, and waste streams resist this softness of solution. They persist as structure rather than substance, as entanglement rather than clarity. And when we force them into dissolution, we often pay a hidden price: in solvents, in energy, in separations that undo what was just achieved. At some point, a question quietly emerges, almost uncomfortably simple: do we still rely on solution chemistry because it is the most fitting language, or because it is the one we inherited most completely ?

Mechanochemistry enters like a change of weather in this landscape of thought. It is often described as chemistry without solvent, but this description feels too pale for what is actually shifting. The solvent is not simply removed, it is replaced by something more restless, more physical, more alive in its instability. Under milling or extrusion, reactions unfold in a world of impacts and fractures, of fleeting contacts and sudden pressures, of heat born and lost in the same instant. Interfaces appear and disappear. Matter is continuously rewritten by force.

In such a world, the medium is no longer a silent stage for molecules. It becomes an actor in the drama. Solids are no longer passive containers of chemical identity, but landscapes under tension; folding, breaking, renewing themselves with every mechanical gesture. Even the reactor ceases to be neutral; its material, its geometry, its rhythm of impact all leave fingerprints on what becomes possible. Chemistry shifts subtly, but profoundly, from a question of molecules in space to a question of matter in motion.

Nowhere is this more evident than in polymers. They are too large for the elegance of simple molecular pictures, too entangled for the calm of equilibrium thinking, too historically shaped to behave as if the past does not matter. And yet they sit at the heart of our material world, and of its most pressing transformations. Recycling, upcycling, circularity; all of these require us to speak to matter that refuses to dissolve without remainder. Mechanochemical approaches, especially through milling or reactive extrusion, offer another kind of dialogue: one that does not begin by dissolving the material, but by pressing it into transformation as it is.

Of course, this language is still young. It does not yet have the grammar of a century of solution chemistry. It stumbles on questions of scale, of reproducibility, of energy that is felt more than fully measured. It still learns how to describe itself. But perhaps its importance lies precisely there, not in replacing an established language, but in revealing that another one was always possible.

Because it may be that many of the transformations ahead will not unfold in quiet, dilute solutions, but in dense and restless matter, shaped as much by force as by structure, as much by motion as by identity. Chemistry once learned to master molecules in solution. Mechanochemistry gently suggests something else: that matter, when set in motion, may still have more to tell us than we have yet learned to hear.

The articles listed below are available as subpages under this section:

• Do Great Scientific Advancements Come from Solitude or Collaboration ?
• The Hidden Struggles of Being a University Researcher-Teacher
• The Future of AI in Polymer Chemistry: Enhancing Research and Education
• Is Flow Chemistry realistic for an industrial polymer production?
• Converting waste plastics into value-added materials by putting carbon dioxide (CO₂) to work
• Why thinking looks like doing nothing ?
• Does Love Shapes Our Career Choices?