Redox-Responsive Polymer with Self-Immolative Linkers for the Release of Payloads.

Previous couplings of corrosion inhibitors to redox-responsive polymers via covalent bonding suffer from several drawbacks. It is presented here novel redox-responsive polymer-corrosion inhibitor conjugates that contain self-immolative linkers in their side chains. Very fast redox-induced release of tryptamine, a drug and a corrosion inhibitor, is observed after applying a reductive trigger.

Light-activated helical inversion in cholesteric liquid crystal microdroplets.

Cholesteric liquid crystal (CLC) droplets exhibit nontrivial topological features, which are controlled by the ratio between the cholesteric pitch and the droplet radius. The radial spherical structure (RSS) is of particular interest, as it reveals an onion-like concentric organization of the cholesteric helices, leading to the expression of spherical Bragg microcavities. Using an overcrowded alkene-based unidirectional molecular motor as a dopant, we show that the topological defect structure in the droplet can be activated by illumination.

Revolving supramolecular chiral structures powered by light in nanomotor-doped liquid crystals.

Molecular machines operated by light have been recently shown to be able to produce oriented motion at the molecular scale as well as do macroscopic work when embedded in supramolecular structures. However, any supramolecular movement irremediably ceases as soon as the concentration of the interconverting molecular motors or switches reaches a photo-stationary state. To circumvent this limitation, researchers have typically relied on establishing oscillating illumination conditions-either by modulating the source intensity or by using bespoke illumination arrangements.

High-Power Actuation from Molecular Photoswitches in Enantiomerically Paired Soft Springs.

Motion in plants often relies on dynamic helical systems as seen in coiling tendrils, spasmoneme springs, and the opening of chiral seedpods. Developing nanotechnology that would allow molecular-level phenomena to drive such movements in artificial systems remains a scientific challenge. Herein, we describe a soft device that uses nanoscale information to mimic seedpod opening.

Preparation of biomimetic photoresponsive polymer springs.

Polymer springs that twist under irradiation with light, in a manner that mimics how plant tendrils twist and turn under the effect of differential expansion in different sections of the plant, show potential for soft robotics and the development of artificial muscles. The soft springs prepared using this protocol are typically 1 mm wide, 50 μm thick and up to 10 cm long. They are made from liquid crystal polymer networks in which an azobenzene derivative is introduced covalently as a molecular photo-switch.

Fluorinated Azobenzenes for Shape-Persistent Liquid Crystal Polymer Networks.

Liquid crystal polymer networks respond with an anisotropic deformation to a range of external stimuli. When doped with molecular photoswitches, these materials undergo complex shape modifications under illumination. As the deformations are reversed when irradiation stops, applications where the activated shape is required to have thermal stability have been precluded.

Conversion of light into macroscopic helical motion.

A key goal of nanotechnology is the development of artificial machines capable of converting molecular movement into macroscopic work. Although conversion of light into shape changes has been reported and compared to artificial muscles, real applications require work against an external load. Here, we describe the design, synthesis and operation of spring-like materials capable of converting light energy into mechanical work at the macroscopic scale.

Time-programmed helix inversion in phototunable liquid crystals.

Doping cholesteric liquid crystals with photo-responsive molecules enables controlling the colour and polarisation of the light they reflect. However, accelerating the rate of relaxation of these photo-controllable liquid crystals remains challenging. Here we show that the relaxation rate of the cholesteric helix is fully determined by helix inversion of the molecular dopants.