Polyethylenimine (PEI) or polyaziridine is a polymer with repeating unit composed of the amine group and two carbon aliphatic CH2CH2 spacer. Linear polyethyleneimines contain all secondary amines, in contrast to branched PEIs which contain primary, secondary and tertiary amino groups. Totally branched, dendrimeric forms were also reported. PEI is produced on industrial scale and finds many applications usually derived from its polycationic character.
Linear PEI fragment Typical branched PEI fragment PEI dendrimer generation 4

Application: Under certain conditions, polyethylene imine solid material can absorb a large amount of carbon dioxide in moist air, and the separation process is very convenient. Carbon dioxide can be permanently sequestered in polyethylene imine solids or extracted for use in other fields. The material can be reused, and maintains ultra-high absorption efficiency as before. Polyethylenimine also has a strong adhesion ability, can effectively make the cell adhesion, but polyethylenimine also has a strong toxicity.