The application of cyclic polymers in surface functionalization enables an extremely broad modulation of interfacial physicochemical and functional properties, surpassing the attractive characteristics provided by commonly applied, linear polymer “brushes”.<br/>This is valid on macroscopic, inorganic surfaces, where chemically inert, cyclic polymer brushes provide an enhanced steric stabilization of the interface and a superlubricious behavior. Alternatively, when cyclic brushes form shells on inorganic nanoparticles (NPs), their highly compact and ultradense character make them impenetrable and long-lasting shields, which extend the stability of NP dispersions and hinder interactions with serum proteins.<br/>The steric and conformational constraints introduced during cyclization additionally affect the characteristics of polymer assemblies when these feature a functional character. This is the case for polymer interfaces that are chemically designed to actively interact with proteins present in the medium, or, alternatively, which respond to a chemical stimulus by a significant change in their properties.<br/>The augmented effective intramolecular repulsion between polymer segments within cyclic macromolecules does not only determine a higher excluded-volume effect and enhanced solvation, but it additionally leads to an increment in electrostatic repulsive forces when the polymers are ionizable, and provides an increased exposure of functional groups enabling a more efficient binding of biological entities. On the one hand, the amplified responsiveness of cyclic polyelectrolyte brushes broadens the tuning potential for interfacial properties on “smart” surfaces, providing a new molecular design for responsive materials. On the other hand, the increased availability of functions on cyclic brush-bearing surfaces indicates that an enhancement in reactivity towards biological entities can be generalized to different polymer chemistries. If this hypothesis was validated, cyclic polymer assemblies could not only be applied as extremely efficient bioinert surfaces, but they could also act as synthetic supports for biological recognition, improving the performance of nanomedical devices and biosensors.

Topological evolution of functional polymer brushes

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.