Thermal and Liquid Crystalline Properties of a Polymer with Amphiphilic-Mesogenic Side-Chains
- PDF / 266,694 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 49 Downloads / 192 Views
Thermal and Liquid Crystalline Properties of a Polymer with Amphiphilic-Mesogenic Side-Chains Seiji Ujiie†, Yumi Yano‡, and Akira Mori‡ † Department of Material Science, Interdisciplinary Faculty of Science and Engineering, Shimane University, Matsue 690-8504, Japan ‡ Institute of Advanced Material Study, 86, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan ABSTRACT A low-molecular-weight liquid crystalline amphiphilic compound (Az6Bu) and a liquid crystalline polymethacrylate [P(Az6Bu)] with amphiphilic-mesogenic side-chains are reported in this present paper. A polyethyleneimine chain with 2-hydroxyethyl side-groups was used as the water-soluble spacer. Az6Bu exhibited a lyotropic columnar phase and no thermotropic mesophase. P(Az6Bu) showed thermotropic and lyotropic liquid crystalline properties. P(Az6Bu) formed thermotropic smectic A and C mesophases on the heating and cooling processes. The lyotropic systems consisting of P(Az6Bu) and water exhibited a smectic C lyomesophase with oilystreak and schlieren textures. The layered structures formed in the thermotropic and lyotropic mesophases are composed of a sublayer produced by the anisotropic alignment of aromatic-mesogenic groups and a sublayer of hydrophilic groups.
INTRODUCTION Amphiphilic molecules have a hydrophilic part (e.g.: oxyethylene chain) and a hydrophobic part(e.g.: hydrocarbon chain). The amphiphilic molecules can show thermotropic and lyotropic liquid crystalline properties by segregation of the hydrophilic and hydrophobic parts. The amphiphilic molecules with an aromatic-mesogenic moiety in the hydrophobic unit form liquid crystalline phases by interactions between aromatic-mesogenic units as well as anisotropy formed by segregation of the hydrophilic and hydrophobic parts [1]. The amphiphiles can self-assemble into various order structures in solutions and liquid crystalline phases [2]. This nature is of high importance in the field of supramolecular chemistry. Due to the architecture of new molecular assemblies, many research groups synthesized a lot of liquid crystalline systems, in which intermolecular interactions, such as ionic interactions, hydrogen bondings, and electronic donor-acceptor interactions, effectively act, and estimated liquid crystalline structures CC5.19.1
and molecular orderings [2,3]. In recent, new amphiphilic materials, having a hydrophilic polyaziridine chain and a hydrophobic aromatic-mesogenic unit, were synthesized by ring-opening polymerization of aziridine-1-ethanol [4]. Moreover, a polymer having the amphiphilic mesogenic unit as the side-chain was prepared. Here we describe the phase transitions and liquid crystalline behavior in the thermotropic and lyotropic liquid crystalline systems containing these novel amphiphilic mesogens.
EXPERIMENTALS A low-molecular-weight amphiphilic mesogen (Az6Bu) with a butyl azobenzne group was obtained by ring-opening polymerization of aziridine-1-ethanol using 6-bromo-1-[4-(4-butylphenylazo)phenoxy]hexane (Br6Bu) as the polymerization initiator [4]. An amphi
Data Loading...
