Viscoelasticity of nematic liquid crystals at a glance
- Giavazzi, Fabio Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
- Crotti, Stefano Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
- Speciale, Antonio Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
- Serra, Francesca Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
- Zanchetta, Giuliano Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
- Trappe, Véronique Department of Physics, University of Fribourg, Switzerland
- Buscaglia, Marco Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
- Bellini, Tommaso Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
- Cerbino, Roberto Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universitá degli Studi di Milano, Segrate, Italy
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15.05.2014
Published in:
- Soft Matter. - 2014, vol. 10, no. 22, p. 3938–3949
English
Polarised microscopy is shown to be a powerful alternative to light scattering for the determination of the viscoelasticity of aligned nematic liquid crystals. We perform experiments in a wide range of temperatures by using an adapted version of the recently introduced differential dynamic microscopy technique, which enables us to extract scattering information directly from the microscope images. A dynamic analysis of the images acquired in different geometries provides the splay, twist and bend viscoelastic ratios. A static analysis allows a successful determination of the bend elastic constant. All our results are in excellent agreement with those obtained with the far more time-consuming depolarised light scattering techniques. Remarkably, a noteworthy extension of the investigated temperature-range is observed, owing to the lower sensitivity of microscopy to multiple scattered light. Moreover, we show that the unique space-resolving capacities of our method enable us to investigate nematics in the presence of spatial disorder, where traditional light scattering fails. Our findings demonstrate that the proposed scattering-with-images approach provides a space-resolved probe of the local sample properties, applicable also to other optically anisotropic soft materials.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 210182
- DOI 10.1039/C4SM00145A
- Persistent URL
- https://folia.unifr.ch/unifr/documents/303761
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