Polyethylene glycol (PEG) is a biocompatible, synthetic, hydrophilic polyether compound that has many applications, mostly in the medical industry, but also in the chemical and industrial sectors. The structure of the compound is known as H−(O−CH2−CH2)n−OH.
The synthesis of PEG is done by polymerizing ethylene oxide, the main ingredient in antifreeze, using a ring-opening technique, which allows for PEGs of a range of molecular weights and molecular weight distributions to be constructed. This range in weights is what makes it suitable for several uses.
Characteristics of polyethylene glycol
While varying the molecular weight of PEG can have slight effects on its characteristics, mostly on its shape and physical appearance, many characteristics define PEG. It is non-toxic, colorless, inert, odorless, and non-volatile. Also, it is incredibly soluble in water, and organic solvents such as benzene, carbon tetrachloride, and chloroform.
Creating PEG substances of different molecular weights relies on constructing PEG with different length chains. Larger PEG molecules have a greater number of repetitions of their structure compared with smaller ones.