The process of breaking down polymers into smaller subunits through the addition of water molecules is known as hydrolysis. Hydrolysis is a chemical reaction in which a compound is broken down by the addition of water, typically in the presence of an enzyme called a hydrolase. In the case of polymers, hydrolysis reactions cleave the bonds that hold the repeating units (monomers) together. This process results in the breakdown of the polymer into its constituent monomers or smaller oligomers.

Hydrolysis reactions are essential in many biological processes, such as digestion, where enzymes break down complex carbohydrates, proteins, and lipids into simpler molecules that can be absorbed and utilized by the body. In the context of synthetic polymers, hydrolysis can be used as a means of recycling or degrading polymers into reusable or environmentally friendly components.