Photoresponsive Photonic Crystals Constructed From Azobenzene-Grafted Silica Microspheres

Azobenzene compounds have been widely used in many fields and through their response to light they can be used to regulate the properties of ordered structures. In this paper, sub-micrometer colloidal SiO2 spheres are prepared and azobenzene groups are grafted on the surface of SiO2 microspheres. The SiO2 microspheres grafted with azobenzene groups could self-assemble to form photosensitive photonic crystals (PCs), whose photonic bandgaps red-shifted as irradiated by UV light and showed good reversibility.

The photoinduced back-and-forth deformation behavior of poly(arylene ether)s containing bis-azobenzene groups in the main chain

The research on the photoresponsive properties of azobenzene-containing poly(arylene ether)s has received much attention due to their excellent thermal stability. Recently, it has been found that poly(arylene ether)s containing azobenzene...

Azobenzene-functionalized graphene nanoribbons: bottom-up synthesis, photoisomerization behaviour and self-assembled structures

We show the strategy of introducing azobenzene groups into graphene nanoribbons (GNRs), which not only endows GNRs with fast photo-responsiveness but also induces the self-assembly of the GNRs into ultra-long nanowires.

Fast Active Merging of Microdroplets in Microfluidic Chambers Driven by Photo-Isomerisation of Azobenzene Based Surfactants

In this work, we report on the development of a newly synthesized photoactive reversible azobenzene derived surfactant polymer, which enables active and fast control of the merging of microdroplets in microfluidic chambers, driven by a pulsed UV laser optical stimulus and the well known cis-trans photo-isomerisation of azobenzene groups. We show for the first time that merging of microdroplets can be achieved optically based on a photo-isomerization process with a high spatio-temporal resolution. Our results show that the physical process lying behind the merging of microdroplets is not driven by a change in surface activity of the droplet stabilizing surfactant under UV illumination (as originally expected), and they suggest an original mechanism for the merging of droplets based on the well-known opto-mechanical motion of azobenzene molecules triggered by light irradiation.

Cluster–Micelle Transition of a Thermo- and Photoresponsive ABC Triblock Copolymer in an Ionic Liquid

We report the photocontrollable micelle–cluster transition of an ABC-type triblock copolymer in an ionic liquid (IL). Polystyrene-b-poly(ethylene oxide)-b-poly(4-phenylazobenzyl acrylamide-r-N-isopropylacrylamide) (PSt-b-PEO-b-P(AzoBnAm-r-NIPAm)) was synthesised, where PSt is IL-phobic, PEO is IL-philic, and P(AzoBnAm-r-NIPAm) is photo- and thermoresponsive in the IL. At high temperatures, the triblock copolymer forms micelles with PSt cores; furthermore, at low temperatures, micelles self-assemble into clusters induced by the aggregation of P(AzoBnAm-r-NIPAm). Under UV irradiation, the micelles form clusters at lower temperatures than that in the dark because of the change in the solubility of P(AzoBnAm-r-NIPAm) induced by photoisomerisation of the azobenzene groups, indicating that this triblock copolymer has a photocontrollable micelle–cluster transition temperature.

Azobenzene-functionalized polymers by ring-opening metathesis polymerization for high dielectric and energy storage performance

Block copolymers with push–pull azobenzene pendants and core–shell nanostructures exhibited high and regulated dielectric constants by photoisomerization of azobenzene groups, low dielectric loss, and high energy density.