Donor–acceptor Stenhouse adduct functionalised polymer microspheres

Abstract

Polymers that carry donor-acceptor Stenhouse adducts (DASAs) are a very relevant class of light-responsive materials. Capable of undergoing reversible, photoinduced isomerisations under irradiation with visible light, DASAs allow for on-demand...

Visible-Light-Assisted Donor–Acceptor-Stenhouse-Adduct-Based Reversible Photoswitching on a Laser-Structurable OrmoComp Substrate

“…In addition to photoswitching from colored triene-2-ol to colorless cyclopentenone, a thermal reversion of the cyclized molecule back to the open-chain triene-2-ol conformation is very well-known in the solution phase. , However, similar to other photoresponsive molecules like azobenzene, spiropyrane, and diarylethene, the thermal reversion of DASA on the solid surfaces is limited due to intermolecular cohesive forces and still poses problems even today. ,− However, recent advances in the solid-state photoswitching of DASA reveal that the polymer design and molecular distribution can provide enough space for photoisomerization. Furthermore, a recent study of the Wang group revealed that the presence of an ester group influences the thermal reversion of cyclic colorless cyclopentenone to open-chain colored triene-2-ol on solid surfaces, which coincide well with the inherent ester functionality of the OrmoComp chemical system.…”

Visible light-responsive materials: the (photo)chemistry and applications of donor–acceptor Stenhouse adducts in polymer science

“…126 Analogously, N -phenylpropane-1,3-diamine was used to modify cross-linked poly(styrene- co -vinylbenzyl chloride) microspheres, which enabled the formation of third-generation DASAs. 127 Sulfonyl groups in poly(2-ethylsulfonyl-2-oxazoline) gels were substituted with N -ethyl-1,3-propanediamine or N -phenylethylenediamine to obtain secondary alkyl and aryl amines on the polymer (Fig. 10e).…”

“…11) primarily reacted with furan adducts via the less nucleophilic aniline moiety during synthesis. 127 This is likely due to increased steric hindrance for units in closer proximity to the main styryl network. In addition, linker chemistry and rigidity can also dictate thermal or mechanical properties of a polymer.…”

“…Glassy PS-based cross-linked microparticles decorated with DASAs exhibited incomplete bleaching under irradiation and low thermal recovery when dispersed and swollen in toluene. 127 This is likely due to mechanical effects on DASAs within the cross-linked rigid network, whereby the cross-linking inhibits local segmental motion even when the material is swollen in a solvent. In this case, the glassy structure is not affected by increases in temperature ( i.e.…”

“…An integrating sphere was used to monitor DASAs absorption overtime in diffuse reflectance mode, overcoming issues arising from the inherent scattering of a polymer microsphere suspension. 127 As described in Section 2.2, the polymer film preparation method ( e.g. , drop-casting, spin coating, drawing, etc. )…”