Novel Microscopic Approach to Particle Size Evaluation in Colloidal Systems

Round 1

Reviewer 1 Report

I suggested this paper to be accepted with minor revisions

1. Authors emphasize that this paper proposes a novel approach, but I did not get how novel it is based on this paper.

2. Why is the abstract separated into three paragraphs? They should be combined into a single paragraph

3. I found that through out the manuscript, “abundance” was mentioned multiple times in figures, however, mentioned rarely in the main text. I did not find a definition or calculation method for this concept. I understand that this is a concept in statistics and probability, but I am wondering if the authors could provide this information to readers.

Author Response

1. Authors emphasize that this paper proposes a novel approach, but I did not get how novel it is based on this paper.

Answer: We apologize for not being clear in our explanations. We have tried to show better the novelty of the work in the introduction and conclusion sections in the revised version. When we say the paper proposes a novel approach, we mean that we propose a new and easy way of preparing bitumen samples by simply smearing between glass slides to be able to visualize the presence of colloidal particles (asphaltenes) using Optical Microscopy. In order to estimate the particle sizes, we coupled this sample preparation method with image analysis software (Image J; which estimates the ellipticity of the particles) and another software which is data-based and takes into account the ellipsoidal nature (ellipticity) of the particles to provide the area measured in µm. We are aware that microscopic investigation of bitumen’s inner morphology is not a novel concept but it is also true that in order to do this, a high level of instrumental know how and a huge volume of data elaboration is needed to obtain the images such as in the case of AFM. The easy method of glass slide smearing of the sample during sample preparation and the ease with which we can observe the samples under the optical microscope is the novelty we are proposing in this paper.

2. Why is the abstract separated into three paragraphs? They should be combined into a single paragraph

Answer: Thanks for this observation. This has been corrected and the abstract is now contained within a single paragraph.

3. I found that through out the manuscript, “abundance” was mentioned multiple times in figures, however, mentioned rarely in the main text. I did not find a definition or calculation method for this concept. I understand that this is a concept in statistics and probability, but I am wondering if the authors could provide this information to readers.

Answer: We appreciate the reviewer for this brilliant observation. We have added the definition of the term abundance in the revised manuscript in the first paragraphs of section 3. To make things even clearer to the reader, we have also added some other information such as the area limits and the number of classes chosen for our data elaboration and the reason for choosing these limits and classes.

Author Response File: Author Response.pdf

Reviewer 2 Report

The experimental section does not contain crucial details about the particle size calculations neither in case of OM, Cm of AFM. Basically the optical resolution is the limiting factor for determination of particle sizes, while the AFM data is not taking into account the surface related imaging issue. In my opinion, the manuscript holds no novel findings. Publication is not recommended. 

English style is fine, minor mistyped errors occure, which might be easily corrected with spell checking softwares. 

Author Response

Reviewer 2

The experimental section does not contain crucial details about the particle size calculations neither in case of OM, Cm of AFM. Basically the optical resolution is the limiting factor for determination of particle sizes, while the AFM data is not taking into account the surface related imaging issue. In my opinion, the manuscript holds no novel findings. Publication is not recommended.

Answer:

We appreciate the reviewer for this comment. We have added important details on our calculations and the data represented on both the X and Y axes of the graphs for the OM, CM and AFM techniques. For each microscopy technique, we have also added the reasons for choosing the area limits and the number of classes.

We also apologize for not being clear in our explanations regarding the novelty of our work. We have tried to explain better in the revised manuscript in the introduction and conclusion sections. When we say the paper proposes a novel approach, we mean that we propose a new and easy way of preparing bitumen samples by simply smearing between glass slides to be able to visualize the presence of colloidal particles (asphaltenes) using Optical Microscopy. In order to estimate the particle sizes, we coupled this sample preparation method with image analysis software (Image J; which estimates the ellipticity of the particles) and another software which is data-based and takes into account the ellipsoidal nature (ellipticity) of the particles to provide the area measured in µm. We are aware that microscopic investigation of bitumen’s inner morphology is not a novel concept but it is also true that in order to do this, a high level of instrumental know how and a huge volume of data elaboration is needed to obtain the images such as in the case of AFM. In this work, we propose a simpler way to do that. The easy method of glass slide smearing of the sample during sample preparation and the ease with which we can observe the samples under the optical microscope is the novelty we are proposing in this paper.

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear editor

 This paper describes the devising a new method to analyze the dimensions of the colloidal particles of a colloidal system using optical microscopy, confocal laser scanning microscopy, and atomic force microscopy. The authors chose bitumen as a model colloidal system. The topic of this article is of interest to the readers of Applied Science. Prior to publication, I recommend that the authors clarify the following points.

Comments to authors

1.      What does the solid lines in Fig. 2, 3, 4, and 8 mean? The author should add the explanation of the solid lines so the reader will understand the text.

2.      About data elaboration, I am concerned about the lack of statistics in the experimental section. Is there a reason to omit the calculation of a standard deviation?

Author Response

Reviewer 3

1. What does the solid lines in Fig. 2, 3, 4, and 8 mean? The author should add the explanation of the solid lines so the reader will understand the text.

Answer: We appreciate the reviewer for this comment. We have now added the explanation of how the points in the graphs were interpolated to get the trend lines.

2. About data elaboration, I am concerned about the lack of statistics in the experimental section. Is there a reason to omit the calculation of a standard deviation?

Answer: Thanks for this comment. In the results and discussions section, we have now added important details on our calculations and the data represented on both the X and Y axes of the graphs for the OM, CM and AFM techniques.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Manuscript text was somewhat improved. As the novelty lays within the sample preparation and particle detection method, comparison performed within same lab with same samples using literature based well established methods are still lacking.