Hydrodynamic Helical Orientations of Nanofibers in a Vortex

• Published in: Symmetry Vol. 6; no. 2; pp. 383 - 395
• Main Author: Tsuda, Akihiko
• Format: Journal Article Book Review
• Language: English
• Published: Basel MDPI AG 2014
• Subjects: Alignment; Bundling; DNA; Fluid dynamics; Fluid flow; Helical; helical alignment; linear dichroism; nanofiber; Nanofibers; Self assembly; stirring; supramolecular polymer; vortex; Vortices
• ISSN: 2073-8994; 2073-8994
• DOI: 10.3390/sym6020383

In this review article, I report our recent studies on spectroscopic visualizations of macroscopic helical alignments of nanofibers in vortex flows. Our designed supramolecular nanofibers, formed through self-assemblies of dye molecules, helically align in torsional flows of a vortex generated by mechanical rotary stirring of the sample solutions. The nanofiber, formed through bundling of linear supramolecular polymers, aligns equally in right- and left-handed vortex flows. However, in contrast, a one-handedly twisted nanofiber, formed through helical bundling of the supramolecular polymers, shows unequal helical alignments in these torsional flows. When the helical handedness of the nanofiber matches that of the vortex flow, the nanofiber aligns more efficiently in the flowing fluid. Such phenomena are observed not only with the artificial helical supramolecular nanofibers but also with biological nanofibers such as double-stranded DNA.