Publications

Arborescent (dendrigraft) polymers are high-molecular-weight dendritic macromolecules with a regular, multilevel branched topology and a high density of functional end groups in their periphery. Their well-defined architecture, devoid of cross-links or loops, imparts a particle-macromolecule duality that becomes particularly pronounced at interfaces. However, the underlying mechanisms governing their interfacial behavior remain largely unexplored. Here, we elucidate how the unique topology dictates the interfacial organization of water-soluble arborescent polymers. Using an iterative grafting-from approach via single-electron transfer living radical polymerization, we synthesized narrowly dispersed polymers with controlled branching and ultra-high molecular weight of 6.2 x 106 g mol-1. These polymers transition from spherical rigid particles in solution, to highly flexible, two-dimensional conformations upon interfacial adsorption. At solid interfaces, increasing segment density shifts surface morphologies from quasi-2D discs to fried-egg-like structures, as observed by atomic force microscopy and corroborated by dissipative particle dynamics simulations. At liquid-liquid interfaces, the absence of substrate constraints facilitates complete spreading into uniform 2D discs, driven by the energy gain due to polymer-segment adsorption. Furthermore, we uncover that macromolecular crowding and topological constraints inherent to the arborescent architecture dictate the response to compression of the adsorbed polymer layer, contrasting sharply with the behavior of conventional flexible linear or star polymers. The combination of high interfacial activity, spatially adaptable end groups, and extreme molecular flexibility will enable arborescent polymers to adapt to complex interfaces, acting as versatile platforms for multivalent and superselective interactions. These properties open new avenues for designing multivalent nanocarriers and adaptive interfacial materials with cooperative binding effects.

JTD Keywords: Angle neutron-scattering, Architectur, Graft, Microgels, Polymers, Polystyrene-graft-poly(2-vinylpyridine) copolymers, Polystyrenes, Radical polymerization, Set, Unimolecular micelles

Methods for the accurate positioning of nanometric beads on a substrate have been developed over a number of years, and range from serial atomic force microscopy (AFM)techniques for single-bead positioning to parallel techniques for the positioning of large populations of beads in monolayer or multilayer architectures, typically from a liquid suspension. For example, topographic cues have been used for bead-based protein array production, although in this case, there is a random distribution of beads within the topography. Bead patterning has also been achieved in capillaries using a micromolding in capillaries (MIMIC) technique. Line patterns with micrometer widths are possible with this technique, achieving good multilayer organization. For monolayer bead patterning at micrometer dimensions, electrostatic forces and similar electrostatic assemblies using nanoxerography, as well as patterning by selective chemical functionalization, by transfer of particles from a liquid–liquid interface, and by subtracting top–down processes, are possible.

JTD Keywords: Microcontact stripping, Nanostructures, Poly(acrylic acid), Polystyrene, Surface patterning