Focused ion beam for studying cholesteric liquid crystals under submicrometer confinement

Eva Enz; Vera La Ferrara; Giusy Scalia

doi:10.1117/12.2049029

19 February 2014 Focused ion beam for studying cholesteric liquid crystals under submicrometer confinement

Eva Enz, Vera La Ferrara, Giusy Scalia

Proceedings Volume 9004, Emerging Liquid Crystal Technologies IX; 90040T (2014) https://doi.org/10.1117/12.2049029
Event: SPIE OPTO, 2014, San Francisco, California, United States

Abstract

We have visualized the internal structure of electrospun polymer fibers, having liquid crystals in the core, using focused ion beam milling. In this way we were able to correlate observed selective reflection and optical texture, in a specific fiber location, with the corresponding cavity dimensions and shape. It was found that cholesteric liquid crystals exhibit peculiar optical behavior, distinctively different from the one in bulk, when they are confined in sub-micrometer cavities. Because of the reduced dimensions, the pitch of the helix has to change even for tiny variations in cavity size, resulting in changes in the wavelength of the selective reflection. The ion beam milling is a destructive process and it is relevant to consider possible side effects and consequences on the polymer sheath and thus on the revealed cavities. We analyze the heating due to the ion beam exposure calculating the subsequent temperature increase in the polymer and at a polymer-liquid crystal interface. The derived increase of temperature is very small and is not expected to induce any notable change in the polymer cavities.

Citation Download Citation

Eva Enz, Vera La Ferrara, and Giusy Scalia "Focused ion beam for studying cholesteric liquid crystals under submicrometer confinement", Proc. SPIE 9004, Emerging Liquid Crystal Technologies IX, 90040T (19 February 2014); https://doi.org/10.1117/12.2049029

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