title: Helical Polyacetylene-Based Switchable Chiral Columnar Phases: Frustrated Chain Packing and Two-Way Shape Actuator.
abstract: Chiral columns formed by a helical cis-polyphenylacetylene (PPA) derivative P1 are reversibly switched during a phase transition between two chiral columnar phases: the frustrated Φh (3D-SL) phase containing four chains at low temperature and a hexagonal columnar phase Φh at high temperature, accompanied by a simultaneous conformational change. The helix-helix transition along the PPA backbone during the Φh (3D-SL) -Φh transition makes the uniaxially oriented P1 capable of reversibly and reproducibly elongating (132 %) upon heating and contracting upon cooling, exhibiting the behavior of a two-way shape actuator.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, P. R. China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Liu
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China.
authors.forename: Xiang-Kui
authors.initials: XK
authors.lastname: Ren
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, P. R. China.
authors.forename: Ben
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, P. R. China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Yang
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Cao
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China. feng.liu@xjtu.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Institut Charles Sadron, CNRS-Université de Strasbourg, Strasbourg, 67034, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Lotz
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, P. R. China. eqchen@pku.edu.cn.
authors.forename: Er-Qiang
authors.identifier: http://orcid.org/0000-0002-0408-5326
authors.initials: EQ
authors.lastname: Chen
keywords: chirality; frustration; liquid crystals; polymers; two-way shape actuation