Kinetics of Polymer Interfacial Reactions: Polymer Brush Formation by Click Reactions of Alkyne End-Functional Polymers with Azide-Functional Substrates

Grafting To of Bottlebrush Polymers: Conformation and Kinetics

Specifically adsorbed bottlebrush coatings are found in nature as brush-like glycoproteins that decorate biointerfaces and provide antifouling, lubrication, or wear-protection. Although various synthetic strategies have been developed to mimic glycoprotein structure and function, the use of these mimics is still limited because of the current lack of understanding of their adsorption behavior and surface conformation. In this paper, we examine the adsorption behavior of PEG-based, biotinylated bottlebrushes with different backbone and bristle lengths to streptavidin model surfaces in phosphate-buffered saline. By using quartz crystal microbalance, localized surface plasmon resonance, and atomic force microscopy, we learn how bottlebrush dimensions impact their adsorption kinetics, surface conformation, mechanical properties, and antifouling properties. Our bottlebrushes qualitatively mirror the adsorption behavior of linear polymers and exhibit three kinetic regimes of adsorption: (I) a transport-limited regime, (II) a pause, and (III) a penetration-limited regime. Furthermore, we find that the bristle length more dramatically affects brush properties than the backbone length. Generally, larger bottlebrush dimensions lead to reduced molar adsorption, retarded kinetics, weaker antifouling, and softer brush coatings. Longer bristles also lead to less mass adsorption, while the opposite trend is observed for increasing backbone length. In summary, our findings aid the rational design of new bottlebrush coatings by elucidating how their dimensions impact adsorption, surface conformation, and the properties of the final coating.

An isocyanide ligand for the rapid quenching and efficient removal of copper residues after Cu/TEMPO-catalyzed aerobic alcohol oxidation and atom transfer radical polymerization

Three for the price of one: 1,4-bis(3-isocyanopropyl)piperazine allows for the removal of Cu impurities, can quench Cu-catalyzed reactions, and can prevent undesirable Glaser coupling.

The long and the short of polymer grafting

Polymer chains are grafted depending on their size onto solid interfaces, leading to a distortion of the surface grafted size distribution. We herein predict and quanitify this distortion effect, which has critical consequences for functional polymer interface design.

High-Antifouling Polymer Brush Coatings on Nonpolar Surfaces via Adsorption-Cross-Linking Strategy

A new "adsorption-cross-linking" technology is presented to generate a highly dense polymer brush coating on various nonpolar substrates, including the most inert and low-energy surfaces of poly(dimethylsiloxane) and poly(tetrafluoroethylene). This prospective surface modification strategy is based on a tailored bifunctional amphiphilic block copolymer with benzophenone units as the hydrophobic anchor/chemical cross-linker and terminal azide groups for in situ postmodification. The resulting polymer brushes exhibited long-term and ultralow protein adsorption and cell adhesion benefiting from the high density and high hydration ability of polyglycerol blocks. The presented antifouling brushes provided a highly stable and robust bioinert background for biospecific adsorption of desired proteins and bacteria after secondary modification with bioactive ligands, e.g., mannose for selective ConA and Escherichia coli binding.

Facile synthesis and chiral recognition of block and star copolymers containing stereoregular helical poly(phenyl isocyanide) and polyethylene glycol blocks

A new Pd(ii) initiator bearing an alkyne headgroup was designed and synthesized.

Post-polymerization modification of styrene–maleic anhydride copolymer brushes

Amine-anhydride reactions on polymer brushes provide a modular post-modification strategy to functional surfaces.