F. Abdi, R. M. Robin Poirot, M. Dakir, L. Sancey V. Ravaine, R. Auzély‐Velty
Dynamic covalent bonds are established upon molecular recognition of sugar derivatives by boronic acid molecules. These reversible links can be used in a cross‐linking method to fabricate polymer‐based responsive nanosystems. Herein, the design of the first dynamic nanogels made entirely of polysaccharides (PS) is reported. Based on PS chains alternately modified with phenyl boronic acid groups and sugar moieties, these colloids self‐assemble in physiological conditions and combine the biocompatible nature of their PS backbone with the reconfiguration capacities of their cross‐linking chemistry. These dynamic nanogels are easily prepared, stable for a long time, pH responsive, and efficiently internalized by cancer cells.
W. Li, C. Hubert, A. Perro, E. Duguet and S. Ravaine
We report the formation of colloidal polymers consisting of disk-like silica nanoparticles (NPs) with polystyrene (PS) chains at the bottom of their two cavities assembled through reduction of the solvent quality for the PS chains and linked by hydrophobic associations. We show that this NPs assembly exhibits a two-stage process involving reaction-controlled polymerization and diffusion-controlled polymerization. Colloidal polymer networks are produced by the incorporation of three-patch NPs, which serve as branching points between the colloidal chains. By co-assembling preformed homopolymers composed of patchy NPs of different sizes or surface chemical groups, block copolymers are also achieved. This study provides insight into the process of self-assembly of two-patch NPs by precisely designing the components to generate colloidal analogues of linear macromolecular chains.
S. Arnaboldi, B. Gupta, T. Benincori, G. Bonetti, R. Cirilli, A. Kuhn
Transduction of chiral information can be achieved at different length scales. Among all possible approaches, we propose in this work a straightforward concept to transfer chiral features from the molecular level to the shape of macroscopic objects by combining the concepts of inherently chiral oligomers and bipolar electrochemistry. Hybrid freestanding lamellar films, composed of polypyrrole and the two oligomeric antipodes of a chiral monomer, are exposed in solution to a chiral target molecule (i.e. L- and D-DOPA) in the presence of an electric field. This leads to an electrochemically induced deformation of the film, which in fine results in one or the other of two macroscopic enantiomorphs, depending on which stereoisomer is present in the solution.
B. Gupta, L. Zhang, A. Melvin, B. Goudeau, L. Bouffier, A. Kuhn
Rational design and shaping of soft smart materials offer potential applications that cannot be addressed with rigid systems. In particular, electroresponsive elastic materials are well-suited for developing original active devices, such as pumps and actuators. However, applying the electric stimulus requires usually a physical connection between the active part and a power supply. Here we report about the design of an electromechanical system based on conducting polymers, enabling the actuation of a wireless microfluidic pump. Using the electric field-induced asymmetric polarization of miniaturized polypyrrole tubes, it is possible to trigger simultaneously site-specific chemical reactions, leading to shrinking and swelling in aqueous solution without any physical connection to a power source. The complementary electrochemical reactions occurring at the opposite extremities of the tube result in a differential change of its diameter. In turn, this electromechanical deformation allows inducing highly controlled fluid dynamics. The performance of such a remotely triggered electrochemically active soft pump can be fine-tuned by optimizing the wall thickness, length and inner diameter of the material. The efficient and fast actuation of the polymer pump opens up new opportunities for actuators in the field of fluidic or microfluidic devices, such as controlled drug release, artificial organs and bioinspired actuators.
A series of mono‐, di‐, and tri‐topic receptors, in which H‐bonding sites, complementary to those of barbituric acid (BA), are fused, is used to induce the supramolecular assembly of n x m ladders containing 1, 2, or 3 triphenylenevinylene units appended with BA. The topological constraint enforced by the architectures induces through‐space interactions between the electroactive moieties that are reflected in the electronic absorption and emission spectrum. The n =2, m =2 or m =3 architectures undergo two single electron oxidation events indicative of the formation of the corresponding mono‐ and di‐radical cation species with comproportionation constants of 340 and 70, respectively. Comparison of the electrochemical potentials suggests that the charges are delocalized over the electroactive units in the assembly.
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