Critical cleaning in biological and pharmaceutical industries depends upon a critical characteristic of water.

Critical cleaning in finishing, manufacturing, and research has to overcome that characteristic of water.

Our life, our planet, health, and even critical cleaning depend on it: hydrogen-bonding within water.

IT’S ABOUT HYDROGEN-BONDING
The oxygen atom in water dominates its properties, and its mass, because that atom is extremely electronegative. A covalent (electron-sharing) bond betweenthe oxygen and the two hydrogen atoms holds the molecule together.

The more electronegative oxygen atom in water draws shared electrons more closely to itself than do the two hydrogen atoms draw electrons to themselves. This charge imbalance produces a steady-state electrostatic dipole within a water molecule. The dipole results in a displacement angle between the two hydrogen atoms of about 105 degrees.

UNIQUE PROPERTIES OF WATER
An oxygen atom is still capable of sharing electrons with water molecules outside the one it populates. So liquid water molecules associate as networks. Individual ones are very hard to separate. It is this condition which is responsible formost of the unique properties of water.

• Oxygen boils at -183 °C. Water boils at 100 °C. That’s the effect of two hydrogen atoms.
• It takes five times as much energy to vaporize (separate) water molecules and two times as much energy to heat them as it does for heptane.
• Water prefers to exist in sheets or films. Its surface tension is 71.4 dynes/cm. That of heptane is 18.5.

AND IT’S ABOUT LIFE
Water is the foundation of life on this planet. It does so by allowing (not enabling) at least two processes: (1) replication to yield new cellular material, and (2) energy transfer between molecules. Both processes require many ofthe body’s solutes to dissolve in water, and they do.

CLEANING IN LIFE SCIENCES
It’s not perfectly true, but nearly so: most “soil” materials removed by critical cleaning in biological or pharmaceutical research or manufacturing are water soluble. Also not perfectly true, but nearly so: the only allowedresidues on these cleaned surfaces are purified water and air.

Why wouldn’t one clean with the one solvent most common to use by the customer of the itembeing cleaned?

CLEANING IN MECHANICAL OR ELECTRICAL SCIENCES
In critical cleaning, water is often a displacement agent, chosen because most organic fluids are immiscible with it. Water is often used to dislodge particlesbecause sonic waves are transmitted so well in it.