Photoswitchable block copolymers based on main chain α-bisimines

Thai, Linh Duy; Guimarães, Thiago R.; Spann, Sebastian; Goldmann, Anja S.; Golberg, Dmitri; Mutlu, Hatice; Barner‐Kowollik, Christopher

doi:10.1039/d2py00994c

Cited by 12 publications

(18 citation statements)

References 55 publications

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“…Die Temperatur, bei der sich die ursprüngliche Masse um 5 % verringert, T d,5% , beträgt 298 °C für (88 % Z )‐P h1 und 302 °C ( Z )‐P h2 (Abbildung S9), was darauf hindeutet, dass die beiden Polymere trotz ihrer relativ niedrigen scheinbaren durchschnittlichen Molmassen ( M n =6 000–8 000 g ⋅ mol −1 ) eine ausgezeichnete thermische Stabilität aufweisen. Diese Werte, d.h. T d,5% , ähneln denen, die für α‐Bisimin‐ADMET‐Polymere mit α‐Bisimin‐Photoschaltern entlang der Hauptkette berichtet wurden [18] . Anschließend wurden DSC‐Messungen an den Polymeren vor und nach der Photoisomerisierung durchgeführt.…”

Section: Ergebnisse Und Diskussionunclassified

Makromolekulare Hydrazon Hauptkettenphotoschalter

Duy Thai,

Fanelli,

Munaweera

et al. 2023

Angewandte Chemie

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Hydrazone – bestehend aus einer dynamischen Iminbindung und einem sauren NH‐Proton – haben sich in letzter Zeit aufgrund ihrer Fähigkeit zur Bildung thermisch bistabiler (Z) bzw. (E) Isomere als vielseitige Potoschalter erwiesen. In diesem Artikel stellen wir zwei lichtsensitive Homopolymere vor, die strukturell unterschiedliche Hydrazone als sich wiederholende Einheiten in der Hauptkette enthalten und durch „Kopf‐Schwanz“‐Polymerisation mittels azyklischer Dien‐METathese (ADMET) synthetisiert wurden. Der Hauptunterschied der beiden Polymere liegt dabei im Design des Hydrazon‐Photoschalters, insbesondere in der Lage des aliphatischen Arms, der den Rotor mit dem aliphatischen Polymerrückgrat verbindet. Es zeigt sich, dass sich das hydrodynamische Volumen der Polymere in verdünnter Lösung während der Photoisomerisierung (λ=410 nm) in entgegengesetzter Weise ändert. Darüber hinaus zeigt sich nach der Photoisomerisierung eine Veränderung der Glasübergangs‐temperatur (Tg) um fast 10 °C bei beiden Polymeren, unabhängig vom Design des jeweiligen Hydrazon‐Monomers. Die hier vorgestellte Designstrategie erlaubt es, makromolekulare Eigenschaften durch Strukturänderungen photochemisch zu kontrollieren.

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Section: Ergebnisse Und Diskussionunclassified

Makromolekulare Hydrazon Hauptkettenphotoschalter

Duy Thai,

Fanelli,

Munaweera

et al. 2023

Angewandte Chemie

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“…17 Most stimuli-responsive moieties are tethered directly to the polymer chain as either pendant groupsor to a far lesser extentas main-chain active groups via ester and amide bonds. [18][19][20][21][22] In the realm of SPs, the type of the substituents decorating the SPs, e.g., electron-withdrawing or electrondonating, has a potentially signicant inuence on the stimuli-sensitiveness of SPs-based polymers. [23][24][25] However, the impact of ester groups located at different sites of SPs' aromatic moieties (regioisomers) has not been investigated.…”

Section: Introductionmentioning

confidence: 99%

Photo- and halochromism of spiropyran-based main-chain polymers

Thai,

Kammerer,

Mutlu

et al. 2024

Chem. Sci.

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“…Within the main-chain, the photoswitch can be introduced as the initiator or end-capping species, whereby a single photoswitch ends up at the chain end or in the middle of the polymer/junction of a block copolymer. Multiple incorporation of photoswitches into the main-chain is, however, less frequent as it often requires a multistep synthesis of polymerizable photoswitches that are subsequently converted into polymers by, e.g., controlled radical, metathesis, − condensation, − addition, − and click-reaction polymerization techniques. The common drawback of these strategies is that each polymer requires the synthesis of a unique monomer, which includes the establishment ofcustomizedpurification procedures capable to achieve high monomer purity (cf.…”

Section: Introductionmentioning

confidence: 99%

Photoswitches in Order: One-Pot Synthesis of Azobenzene Main-Chain and Segmented Copolymers

Rossi,

Martella,

Parmeggiani

et al. 2024

ACS Appl. Polym. Mater.

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Syntheses of multifunctional polymers aim to engineer a wide range of material properties by adjusting the composition and positioning of functional groups. While manifold syntheses of sidechain-functionalized polymers are known, synthetic protocols for main-chain-functionalized polymers are less common. This work describes a general one-pot strategy to prepare polymers containing multiple functional moieties in their main-chain, e.g., azobenzene units separated by variable oligomers. The polymerization proceeds in two steps, starting from a single azobenzene initiator and commercially available monomers (lactones and cyclic carbonates). Various main-chain-functionalized polymers were obtained with a predictable and adjustable ratio of monomer units (5−20) to photoswitchable azobenzene groups. The thermal properties of these polymers were analyzed and rationalized with regard to the parent polymers' properties and the peculiarities arising from their segmented microstructure. Furthermore, the azobenzenes' ability to undergo light-induced cis/trans-isomerization is confirmed. High isomerization yields of up to 90% were observed for the polymers in solution with a half-life of several days for the cis-isomers in solution. When irradiated as solid films, the azobenzenes still undergo isomerization, but the cis-isomers are less stable compared to the liquid state.

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Photoswitchable block copolymers based on main chain α-bisimines

Abstract: We introduce linear diblock copolymers (BCPs) consisting of readily accessable and photoswitchable α-bisimine units in the polymer backbone. The BCPs are prepared via a combination of activators regenerated by electron...

Cited by 12 publications

References 55 publications

Makromolekulare Hydrazon Hauptkettenphotoschalter

Makromolekulare Hydrazon Hauptkettenphotoschalter

Photo- and halochromism of spiropyran-based main-chain polymers

Photoswitches in Order: One-Pot Synthesis of Azobenzene Main-Chain and Segmented Copolymers

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