Bending control of liquid-crystal elastomers based on doped azo derivatives synthesized via controlled gradient polymerization

S. Fitriyani, C. Y. Liu, Y. H. Hung, Y. S. Zhang, J. H. Liu

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The intelligence, complexity, and diversification of nature is a continuous source of inspiration for humankind. Imitating natural intelligence to devise bionic microrobots with self-regulated features remains an enormous challenge. Herein, we demonstrate a biomimetic soft material that uses light to trigger mechanical motion. This light-sensitive mimosa mimetic film was designed based on liquid crystal elastomers (LCEs) and photoisomerizable azo compounds. To control the bending direction, a predesigned UV-induced gradient polymerization was used. The energy-controlled polymerized film comprises one high-density and one low-density liquid crystal mesogen face. Similar to mimosas, the fabricated films achieved stimuli-responsive actuation, exhibiting shape deformation upon light illumination. The elastic network undergoes reversible shape changes via photochemical trans-cis isomerization of an azo compound in response to a stimulus. In this study, only a small amount of photoisomerizable 1-Hydroxy-n-(4-nitro-azobenzene-4'-oxy)hexane (AZO) was used; however, the domino effect caused a significant reversible actuation. The mesogen density of the top and bottom faces was found to be an important factor for the bending control. This study explores a new way to fabricate films that can bend in controlled directions during light irradiation. This phototunable film is expected to be used for applications in microrobotics and micromachinery.

Original languageEnglish
Pages (from-to)566-575
Number of pages10
JournalExpress Polymer Letters
Issue number6
Publication statusPublished - 2020 Jun

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

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