Jump to main content
Jump to site search

Issue 10, 2021
Previous Article Next Article

Treating anisotropic artefacts in circular dichroism spectroscopy enables investigation of lyotropic liquid crystalline polyaspartate solutions

Author affiliations

Abstract

Circular dichroism (CD) spectroscopy is commonly used for investigation of the secondary structure of biomolecular compounds as well as polymers in isotropic solution. In anisotropic solution, the usage of the apparent CD is prone to misinterpretations due to artefacts from contributions of e.g. linear dichroism (LD). Herein, a method for the complete cancelation of anisotropic artefacts in the apparent CD is developed and its validity proven. The approach is further used for investigation of the conformation and the lyotropic liquid crystalline (LLC) structure of a copolyaspartate. For this system, a temperature-dependent change of the polymer's helical conformation (helix reversal) is known. Furthermore, a rotation of the aligned polymer helices inside a magnetic field (helix realignment) is independently present, occurring at a lower temperature compared to the helix reversal. In the current study, the helix reversal is confirmed and found to be accompanied by a change of the LLC structure. A cholesteric structure is detected and revealed to change its sense (cholesteric reversal) at the temperature at which the helix realigns in the magnetic field. The determination of the cholesteric sense is enabled by measuring the induced CD of an achiral dye, dissolved in the anisotropic polymer solution. Investigation of the anisotropic polymer solution is, thus, only made possible by cancellation of the aforementioned anisotropic artefacts. This allows the observation of changes of the liquid crystal structure from right-handed cholesteric, through left-handed cholesteric, to nematic with increasing temperature.

Graphical abstract: Treating anisotropic artefacts in circular dichroism spectroscopy enables investigation of lyotropic liquid crystalline polyaspartate solutions

Back to tab navigation

Supplementary files

Article information


Submitted
25 Nov 2020
Accepted
25 Jan 2021
First published
26 Jan 2021

Soft Matter, 2021,17, 2849-2856
Article type
Paper

Treating anisotropic artefacts in circular dichroism spectroscopy enables investigation of lyotropic liquid crystalline polyaspartate solutions

M. Hirschmann, C. Merten and C. M. Thiele, Soft Matter, 2021, 17, 2849 DOI: 10.1039/D0SM02102D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements