HELICAL STRUCTURES FROM ACHIRAL BIPHENYL CARBOXYLIC ACID MOLECULES
Helical structures were constructed from achiral 4biphenyl carboxylic acid molecules (BPCA-Cn-PmOH) connected with phenol at meta-position by alkoxyl chains with various carbon numbers. In order to understand the origin of helical structures, four other achiral 4-biphenyl carbonyl model compounds were studied using a combination of techniques. to recognize the importance of hydrogen (H)-bonding between hydroxyl groups and the small kink at the end of the phenyl groups, the hydroxyl group at the metaposition of phenyl groups in BPCA-C6-PmOH was first moved to the para-position to become BPCA-C6-PpOH, and then changed to a methoxy group to become BPCAC6-PmOH3. BPCA-C6-P, having no functional groups on the phenyl groups, was also synthesized. Finally, one more compound was synthesized to disrupt the formation of the H-bonded head-to-head dimers by replacing the H group on the carboxylic acid with an ethyl group to become BPCE-C6-PmOH. Phase structures of this series of compounds were characterized by wide-angle X-ray diffraction (WAXD), selected area electron diffraction, and differential scanning calorimetry.
Kwang-Un Jeong Deng-Ke Yang Brian S.Knapp Frank W.Harris Stephen Z.D.Cheng
Department of Polymer-Nano Science and Technology,Chonbuk National University,Jeonju,Jeonbuk 561-756 Liquid Crystal Institute,Kent State University,Kent,Ohio 44242,USA Department of Polymer Science,The University of Akron,Akron,Ohio 44325,USA
国际会议
International Symposium on Polymer Physics(2008年国际高分子物理学术会议PP2008)
厦门
英文
44
2008-06-08（万方平台首次上网日期，不代表论文的发表时间）