# What is a 'corona phase'?

What is a 'corona phase'? I have come across this term in several papers, including this one

but all I have found concerning its definition is:

[...] synthetic heteropolymers, once constrained onto a single-walled carbon nanotube by chemical adsorption, also form a new corona phase that exhibits highly selective recognition for specific molecules...

What is the formal definition of 'corona phase'?