Straightforward preparation of supramolecular Janus nanorods by hydrogen bonding of end-functionalized polymers

Abstract

Janus cylinders are one-dimensional colloids that have two faces with different compositions and functionalities, and are useful as building blocks for advanced functional materials. Such anisotropic objects are difficult to prepare with nanometric dimensions. Here we describe a robust and versatile strategy to form micrometer long Janus nanorods with diameters in the 10-nanometer range, by self-assembly in water of end-functionalized polymers. The Janus topology is not a result of the phase segregation of incompatible polymer arms, but is driven by the interactions between unsymmetrical and complementary hydrogen bonded stickers. Therefore, even compatible polymers can be used to form these Janus objects. In fact, any polymers should qualify, as long as they do not prevent co-assembly of the stickers. To illustrate their applicative potential, we show that these Janus nanorods can efficiently stabilize oil-in-water emulsions.

Thiosquaramide-Based Supramolecular Polymers: Aromaticity Gain in a Switched Mode of Self-Assembly

“…Supramolecular polymers are endowed with unique properties, such as responsiveness and self-healing, − due to the inherent dynamic nature of the noncovalent interactions they are based on, leading to numerous potential applications as biomedical materials, adhesives, inks, or personal care products. − Noncovalent interactions, including hydrogen-bonding, − π-stacking, solvophobicity, and van der Waals, are responsible for their self-assembly into hierarchical architectures through stacking or molecular recognition of polymeric precursors. − Over the past years, the growing number of synthesized monomers has contributed significantly to the development of general design rules to facilitate monomer self-assembly in organic solvents and water. However, to further guide their rational design, it is necessary to understand factors that influence the strengths of competing noncovalent interactions either within a monomer or between them.…”

Oxidation-Sensitive Supramolecular Polymer Nanocylinders

“…The corresponding suspensions were studied by cryogenic transmission electron microscopy (cryoTEM) analysis and light scattering, which revealed the formation of small and weakly aggregated monodisperse spherical particles ( R h = 7 nm and N agg = 44) instead of the targeted one-dimensional assemblies (see the SI, Section 2.3.1). A second preparation pathway, deemed the “DMSO route”, ,, was therefore attempted: PEO-TTF-U 2 was dissolved in dimethyl sulfoxide (DMSO), a strong hydrogen bond competitor that favors its unimer state, and water was slowly added to reach a water/DMSO content of 99:1 (v/v) (see the SI, Section 2.2). CryoTEM experiments revealed that this method mainly leads to the formation of nanocylinders (Figure a), as well as a small amount of spheres.…”

“…The anisotropic character of isolated polymer nanocylinders makes them relevant for varied applications: [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] drug delivery, 19,20 synthesis of mesoporous inorganic materials, 21 catalysis, 22 organic electronics, 23 or emulsion stabilization. 24 Imparting stimuli-responsiveness to supramolecular nanocylinders may allow their disassembly after use, which can be critical to reach reversibly-controlled systems. For example, a reversible destabilisation of an emulsion can be conducted in order to recover the products of a reaction.…”

“…The latter ones protect the one-dimensional structures from lateral aggregation, resulting in isolated nanocylinders in solution. The anisotropic character of isolated polymer nanocylinders makes them relevant for various applications: − drug delivery, , synthesis of mesoporous inorganic materials, catalysis, organic electronics, or emulsion stabilization . Imparting stimuli-responsiveness to supramolecular nanocylinders may allow their disassembly after use, which can be critical to reaching reversibly controlled systems.…”

Hybridization of Poly(oxazoline) and Poly(ethylene oxide)-Based Amphiphilic Copolymers into Thermosensitive Mixed Micelles of Tunable Cloud Point

“…The effective success of this procedure implies that the formation of co-micelles is both thermodynamically and kinetically favorable. The premixing strategy, where both types of polymers are first blended in their unimer state in a nonassociating solvent before triggering co-assembly, ,,,,,, was therefore not required to prepare co-micelles and was not tested.…”