Hyperbranched polymer brushes with a three-dimensional dendritic structure are used in antifouling applications to obtain bioinert and compact dendritic structures. Though hyperbranched polyglycerol (HPG) is extensively utilized in the antifouling layer, there is still a lack of direct studies on the relationship between the interfacial properties and topology effect of hyperbranched polymer brushes. Here, we established the degree of chain volume overlap (D v) to characterize the spatial shielding efficiency generated by HPG brushes and investigated the impact mechanism of the variable chain length on the interfacial physicochemical properties. The results revealed the D v-relevant feature of performance that the most densely packed HPG brushes for a medium-length L HPG3.07 enable the functional surface to display optimal antifouling performance toward protein adsorption by forming the most effective space barrier and hydrated layer in appropriate molecular weights and graft density. Moreover, we clarified the advance of hyperbranched polymer brushes exhibited in topology effects for imparting surface-enhanced resistance to biofouling relies on the generable higher steric hindrance as compared with linear analogs. This study established a D v-relevant evaluation model for acquiring an optimized antifouling surface based on the appropriate choice of polymer structure, topology morphologies, and grafting parameters.

Polymer brushes with different topological architectures exhibit unparalleled interfacial and physicochemical properties and are being widely utilized in antifouling applications. However, there is an absence of a thorough understanding of the antifouling process of dynamic flow mediated by the topological structure of polymer brushes. Here, it is highlighted how the interface parameters related to biofouling in flowing carrier fluid are tuned by topologically different architectures. The mechanism by which three brushes with various topological structures (cyclic, looped, and linear brushes) encounter biological media was revealed by relating protein adhesion with nanomechanics and protein conformational transitions on poly(2-ethyl-2-oxazoline) (PEtOx) brushes. In contrast to the classically linear analogue, the cyclic PEtOx brushes confered an enhanced steric barrier and excellent lubrication at the critical density region. The impenetrable and smoother layer prevented the approach and shortened the residence time for protein on the surface, providing optimal antifouling properties at low shear rates. The looped brushes also significantly inhibited protein adhesion under prolonged high shear rates due to their unshakable conformational characteristics. These findings detailed a new evaluation framework behind polymer brushes of topology-driven biofouling repulsion under flow conditions and pointed the way toward a promising approach for the effectiveness of biomaterial design.