Details

Autor(en) / Beteiligte

• Rodríguez-González, Rosa Julia
• Ramos-Díaz de León, Alicia
• Hernández-Hernández, Ernesto
• Larios-López, Leticia
• Ruiz-Martínez, Antelmo Yasser
• Felix-Serrano, Isaura
• Navarro-Rodríguez, Dámaso

Titel

Enhancement of the photoinduced birefringence and inverse relaxation of a liquid crystal azopolymer by doping with carbon nanostructures

Ist Teil von

• Journal of photochemistry and photobiology. A, Chemistry., 2023-02, Vol.435, p.114342, Article 114342

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2023

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• [Display omitted] •Carbon nanotubes can enhance the photoinduced birefringence of azopolymers.•The in situ doping method provides a good polymer-nanotube interaction.•The occurrence of the inverse relaxation depends on the doping method. In this work, the effect of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on the photoinduced behavior of one side-chain liquid crystal azopolymer is studied. Two distinct methods of doping the azopolymer with CNTs or CNFs are followed: during (in situ method) and after (mixing method) polymerization. Thermotropic studies show that dopants do not have a significant effect on the liquid-crystalline properties of the azopolymer, which develops a smectic A-type phase whose lamellar structure is preserved after cooling to room temperature. On the other hand, the light-induced birefringence of the azopolymer doped by the in situ method (∼0.095) is higher than that reached with the corresponding one doped by the mixing method (∼0.05). In switch-on/switch-off experiments, both the typical and the inverse relaxation processes of the photoinduced orientation are observed. The inverse relaxation occurs only in the azopolymer doped by the in situ method, which seems to provide a good interaction between the azobenzene units and the nanostructures. In addition, it was found that no minimal threshold value of irradiation dose is required to make the inverse relaxation happen. A model based on non-covalent interactions is proposed to explain the inverse relaxation promoted by nanostructures introduced by the in situ method.