When people hear “plasma cleaning,” it can sound abstract. In reality, the work is done by very real chemistry, especially by hydroxyl radicals (•OH).

In IonField’s atmospheric plasma process, generated from room air, several reactive species are formed. Hydroxyl radicals are one of the most important tools in our toolbox. Together, these short-lived reactive species drive efficient, surface-focused cleaning.

What Is a Hydroxyl Radical?

A hydroxyl radical is an extremely reactive oxidizing molecule formed when oxygen and trace water vapor in air are energized in a plasma state.

They are:

• Highly reactive

• Very short-lived

• Powerful oxidizers of organic material

In atmospheric chemistry, •OH radicals have been called the “detergent of the atmosphere” because they break down pollutants. In plasma cleaning, they serve a similar function, but in a controlled, surface-limited environment.

How They Remove Residue

On polymer labware like polypropylene microplates and pipette tips, residues cling due to surface energy and physical adsorption. Traditional washing relies on soaking, detergents, and drying.

Hydroxyl radicals work differently.

When •OH contacts organic contamination, it:

• Breaks carbon–hydrogen and carbon–carbon bonds

• Fragments proteins and biomolecules

• Converts residues into volatile byproducts like CO₂ and water vapor

Because hydroxyl radicals exist only for microseconds, they react immediately at the surface and then disappear. There is no bulk chemical bath and no lingering residue.

Surface-Focused Chemistry

IonField’s process operates in a surface-flux–limited oxidation regimen. Reactive species, including hydroxyl radicals, are generated at or near the air-liquid interface and consumed before diffusing into the surrounding bulk material.

That means:

• No penetration into the plastic

• No chemical carryover

• No downstream drying bottlenecks

• No consumable oxidizers

Any residual water introduced is evaporated within the plasma environment.

One Tool Among Many

Hydroxyl radicals are powerful, but they’re part of a broader reactive chemistry system produced by atmospheric plasma. Different species contribute to cleaning, oxidation, and surface normalization in complementary ways.

This is not a single-chemical process. It’s a controlled, multi-species surface treatment.

Why It Matters

Polypropylene is difficult to clean because contamination is a surface physics problem, not just a chemistry problem. Plasma-generated reactive species allow us to address residues at the molecular level, without harsh solvents, specialty gases, or consumables.

Hydroxyl radicals do much of the heavy lifting. But the real advantage is the controlled plasma environment that deploys the right tools, exactly where they’re needed, at the surface.