Supramolecular Self-Assembly of Discotic
Liquid Crystalline LEGOs
8
Lei Zhu
Contents
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Self-assembly of Doubly Discotic Liquid Crystalline Supermolecules . . . . . . . . . . . . . . . . . . . . . . . . 220
Self-assembly of Disk-Cube Liquid Crystalline Supermolecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Abstract
Discotic liquid crystals with well-defined columnar self-assemblies are promising
for technological applications in organic electronics such as organic solar cells
and field-effect transistors. In this entry, we review the self-assembly behavior of
discotic supermolecules comprised of various discotic and cubic building blocks,
including porphyrin, phthalocyanine, triphenylene, and polyhedral oligomeric
silsesquioxane (POSS). With the help of amide hydrogen bonding, triphenylenes
and porphyrins stack into the ordered “lamello-columnar” phase. Without hydrogen bonding interaction, the π-π stacking interaction leads to a hexagonal columnar phase with mixed phthalocyanine and triphenylene columns. For a POSS
molecule covalently attached to eight triphenylenes, the triphenylenes and the
POSS core can form a super-column when the space length is short. Selfassembly of these supercolumns can lead to a hexagonal superlattice. From this
study, the spacer length, molecular geometry/size, and intermolecular interactions
play an important role in the self-assembly of the discotic liquid crystalline
LEGOs.
L. Zhu (*)
Department of Macromolecular Science and Engineering, Case Western Reserve University,
Cleveland, OH, USA
e-mail: lxz121@case.edu
© Springer Nature Switzerland AG 2020
L. Zhu, C. Y. Li (eds.), Liquid Crystalline Polymers, Polymers and Polymeric
Composites: A Reference Series, https://doi.org/10.1007/978-3-030-43350-5_65
217
Liquid Crystalline LEGOs
8
Lei Zhu
Contents
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Self-assembly of Doubly Discotic Liquid Crystalline Supermolecules . . . . . . . . . . . . . . . . . . . . . . . . 220
Self-assembly of Disk-Cube Liquid Crystalline Supermolecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Abstract
Discotic liquid crystals with well-defined columnar self-assemblies are promising
for technological applications in organic electronics such as organic solar cells
and field-effect transistors. In this entry, we review the self-assembly behavior of
discotic supermolecules comprised of various discotic and cubic building blocks,
including porphyrin, phthalocyanine, triphenylene, and polyhedral oligomeric
silsesquioxane (POSS). With the help of amide hydrogen bonding, triphenylenes
and porphyrins stack into the ordered “lamello-columnar” phase. Without hydrogen bonding interaction, the π-π stacking interaction leads to a hexagonal columnar phase with mixed phthalocyanine and triphenylene columns. For a POSS
molecule covalently attached to eight triphenylenes, the triphenylenes and the
POSS core can form a super-column when the space length is short. Selfassembly of these supercolumns can lead to a hexagonal superlattice. From this
study, the spacer length, molecular geometry/size, and intermolecular interactions
play an important role in the self-assembly of the discotic liquid crystalline
LEGOs.
L. Zhu (*)
Department of Macromolecular Science and Engineering, Case Western Reserve University,
Cleveland, OH, USA
e-mail: lxz121@case.edu
© Springer Nature Switzerland AG 2020
L. Zhu, C. Y. Li (eds.), Liquid Crystalline Polymers, Polymers and Polymeric
Composites: A Reference Series, https://doi.org/10.1007/978-3-030-43350-5_65
217