Photo‐Imprinting of the Helical Organization in Liquid‐Crystal Networks Using Achiral Monomers and Circularly Polarized Light. Issue 15 (18th February 2022)

• Record Type: Journal Article
• Authors: Sakaino, Hirotoshi; Broer, Dirk J.; Meskers, Stefan C. J.; Meijer, E. W.; Vantomme, Ghislaine
• Is Part Of: Angewandte Chemie international edition. Volume 61:Issue 15(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-18
• Subjects: Chirality -- Cholesteric Liquid Crystals -- Circularly Polarized Light -- Mesogens -- Nanostructures; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202200839
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Control over molecular motion is facilitated in materials with highly ordered nanoscale structures. Here we report on the fabrication of cholesteric liquid‐crystal networks by circularly polarized light irradiation, without the need for chiral dopant or plasticizer. The polymer network is obtained by photopolymerization of a smectic achiral diacrylate mesogen consisting of an azobenzene core and discrete oligodimethylsiloxane tails. The synchronous helical photoalignment and photopolymerization originate from the cooperative movement of the mesogens ordered in well‐defined responsive structures, together with the flexibility of the oligodimethylsiloxane blocks. The resulting thin films show excellent thermal stability and light‐induced memory features with reversible responses. Additionally, we demonstrate the fabrication of photo‐patterned films of liquid‐crystal networks with opposite helical senses. These findings provide a new method to make light‐controllable chiroptical materials with exciting applications in optics and photonics. Abstract : A method has been developed to make cholesteric liquid‐crystal networks from achiral monomers by irradiation with circularly polarized light. This approach allows simultaneous control over the photoalignment of the mesogens and the photopolymerization of the network.