title: Cation-tuned stimuli-responsive and optical properties of supramolecular hydrogels.
abstract: Hierarchical self-assembly of an amphiphilic tris-urea in aqueous media is shown. A mixture of the amphiphilic tris-urea and an alkaline solution gave a viscous solution composed of fibrous aggregates. This viscous solution transformed into supramolecular hydrogels, which are capable of hierarchically organizing into higher-order aggregates in response to several cationic triggers. The resulting supramolecular hydrogels were relatively stiff and their storage moduli attained over 10(3)  Pa. The stimuli-responsive and optical properties of the resulting hydrogels were influenced by the cationic trigger. Proton and calcium ion triggers gave pH- and chemical stimuli-responsive hydrogels, respectively. A terbium ion trigger also provided a highly luminescent hydrogel through energy transfer from the tris-urea to terbium.
authors.affiliation: Department of Chemistry, Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan. yamanaka.masamichi@shizuoka.ac.jp.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Yamanaka
authors.affiliation: Department of Chemistry, Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Yanai
authors.affiliation: College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5258, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Zama
authors.affiliation: College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5258, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Tsuchiyagaito
authors.affiliation: Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5258, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Ishii
authors.affiliation: College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5258, Japan. hasemiki@chem.aoyama.ac.jp.
authors.forename: Miki
authors.initials: M
authors.lastname: Hasegawa
keywords: energy transfer; gels; lanthanides; self-assembly; supramolecular polymers; ureas