Measuring the Anisotropy in Interfacial Tension of Nematic Liquid Crystals
Round 1
Reviewer 1 Report
The manuscript "Measuring the Anisotropy in Interfacial Tension of Nematic Liquid Crystals " by Honaker et al. reports ion measurement of the anisotropy of the surface tension at a water/nematic interface using a microfluidic droplet aspiration technique. This work is motivated mainly because "traditional" methods of surface tension measurements cannot be applied here. The authors give an accurate measurement of the delta_gamma and provide the estimation of the measurement accuracy. The measurements also show that in the case of 5CB, the liquid crystal prefers tangential alignment of the director at the LC/pure water interface. The authors also discuss the effect of surfactants on the stabilization of the LC orientation.
The manuscript is very well written, and the results of this research are valuable for a broad audience of soft-matter researchers. Therefore, I strongly recommend it for publication.
Author Response
We wish to thank the reviewer for their positive appreciation of our paper and our results. We would like to note that we have added text and additional figures to address the concerns of other reviewers.
Reviewer 2 Report
Authors are declaring to use the microfluidic droplet technique and apply in three different systems in this manuscript, pure water, water/PVA, and water/SDS. Except for the method-used differ from the known publications ref [33] and [35], it seems not showing the exciting results from previous work.
- Does it have any POM observation in these drops?
- Is it possible to add any data for anisotropy property in optical measurement?
Author Response
Authors are declaring to use the microfluidic droplet technique and apply in three different systems in this manuscript, pure water, water/PVA, and water/SDS. Except for the method-used differ from the known publications ref [33] and [35], it seems not showing the exciting results from previous work.
We wish to thank the reviewer for their review of our work.
However, we are somewhat confused by the statement of “showing the exciting results from previous work” and what the reviewer means by this. We would like to re-emphasize that the purpose and point of our work is the measurement of the interfacial tension of a fluid that exhibits alignment-dependent properties. While liquid crystal droplets have become increasingly studied and increasingly used in the past few years for a number of applications, for which we have added additional references to show the increasing use of droplets, the crux of our work is the interfacial tension measurement.
We also wish to mention that we are measuring, in all cases these systems with respect to the liquid crystal 5CB, using only SDS and PVA to obtain and induce the desired alignment conditions.
- Does it have any POM observation in these drops?
We have included example POM images (Fig. 3) for bulk LC droplets in the given aligning conditions in the text. However, we find that POM images were not necessary to verify droplet alignment: the aligning conditions can be confirmed through simple microscopy with one inserted polarizer, which shows a characteristic texture.
- Is it possible to add any data for anisotropy property in optical measurement?
The anisotropy in optical properties is an interesting characteristic worth investigation, but we feel that the measurement such, namely the birefringence, is beyond the scope of this paper. Additionally, our focus is on the interfacial tension anisotropy, which has yet to be reported, while the anisotropy in optical properties has been characterized.
Reviewer 3 Report
Authors study the anisotropy in interfacial tension of a liquid crystal. For this purpose they measure the distortion of liquid crystal droplets in a microfluidic device. Authors present in a simple and clear way why their novel approach is better than standard ones. In my opinion, the manuscript is well written and contains all the technical information. I recommend this manuscript to the publication in Crystals.
Author Response
We wish to thank the reviewer for their positive appreciation of our paper and our results. We would like to note that we have added text and additional figures to address the concerns of other reviewers.
Round 2
Reviewer 2 Report
no
