title: Fast response dry-type artificial molecular muscles with [c2]daisy chains.
abstract: Hierarchically organized myosin and actin filaments found in biological systems exhibit contraction and expansion behaviours that produce work and force by consuming chemical energy. Inspired by these naturally occurring examples, we have developed photoresponsive wet- and dry-type molecular actuators built from rotaxane-based compounds known as [c2]daisy chains (specifically, [c2]AzoCD2 hydrogel and [c2]AzoCD2 xerogel). These actuators were prepared via polycondensation between four-armed poly(ethylene glycol) and a [c2]daisy chain based on α-cyclodextrin as the host component and azobenzene as a photoresponsive guest component. The light-induced actuation arises from the sliding motion of the [c2]daisy chain unit. Ultraviolet irradiation caused the gels to bend towards the light source. The response of the [c2]AzoCD2 xerogel, even under dry conditions, is very fast (7° every second), which is 10,800 times faster than the [c2]AzoCD2 hydrogel (7° every 3 h). In addition, the [c2]AzoCD2 xerogel was used as a crane arm to lift an object using ultraviolet irradiation to produce mechanical work.
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Iwaso
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Takashima
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.|JST-ImPACT, Chiyoda-ku, Tokyo 100-8914, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Harada
mesh_terms: D001391:Azo Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D001696:Biomechanical Phenomena; D020100:Hydrogels / Q000737:chemistry; D008027:Light; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D043862:Rotaxanes / Q000138:chemical synthesis* / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D001391:Azo Compounds; D020100:Hydrogels; D011108:Polymers; D043862:Rotaxanes; D011092:Polyethylene Glycols; C009850:azobenzene