Nanosized Being of Ionic Surfactant Micelles: An Advanced View on Micellization Process
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript presents a novel theoretical model for ionic surfactant micellization, introducing the idea that micelles adopt a fullerene-like structure with a central cavity. It integrates concepts from quantum mechanics, symmetry, and chaos theory to reinterpret micelle dynamics and structural features at the nanoscale and it is a valuable piece of work to be published in Colloids and Interfaces. However, while the authors aim to resolve inconsistencies in classical models, the proposed framework is heavily reliant on assumptions and lacks sufficient experimental evidence to validate its claims. I suggest some revisions to clarify the theoretical foundation better. Additionally, the limitations of the proposed model should be explicitly acknowledged until clear experimental validation is available. My suggestion to improve this work is as following.
1- The sentence (line 75) “Only recently, an understanding has emerged that ‘quantum mechanics and quantum coherence play a central role in chemistry’, also defining basic functioning of biological structures”, is somewhat misleading. Quantum mechanics has been a cornerstone of chemistry for decades.
2- The use of the word “radical” in sentences like “The current classical concept of micelle structure, containing the long-chain hydrophobic radicals (alkanes of 8–18 C atoms) and charged head groups” (line 134) can be replaced with “alkyl group”, which is a more appropriate term for this context.
3- The assumption that “only face centers of fullerene-like structure may be the sites of optimal binding” (line 328) is not well-explained. Why are these sites optimal? This statement needs further elaboration. Similarly in line 341: “also allow us to assume the penetration of water into the upper hydrocarbon layers under hydrostatic water pressure.” The macroscopic pressure force does not fit properly into the microscopic framework of the study unless been clarified.
4- Some claims in the manuscript are difficult to evaluate objectively. For instance, the statement in line 375 lacks sufficient justification: “In particular, since the most stable, widespread and easily synthesized fullerene molecule is C60, one can assume that micelle formed by 60 surfactant ions is the most stable and widespread for surfactant self-organization near CMC.”
5- The manuscript relies on a key assumption regarding an aggregation number of 60. The reference supporting this value (Ref. [40]) should specify the relevant chapter, as the information is hard to locate in the cited book. Furthermore, this value represents typical aggregation number rather than a fixed value, and it can vary significantly under different conditions (please see, for example, https://doi.org/10.1016/j.cis.2012.08.003). So, it is difficult to accept this aggregation number as the foundation of the model. A more realistic approach would account for a polydisperse aggregation number, reflecting the variability typically observed in micellar systems.
6- Citations that include web addresses (lines 560, 573, and 625) should follow standard referencing practices. Please kindly replace direct links with numbered references in the bibliography.
7- The manuscript claims that odd aggregation numbers do not occur (line 417), but this contradicts findings in the literature, such as https://doi.org/10.1021/j100046a031. This inconsistency needs to be acknowledged.
8- There is a lack of strong simulation or experimental evidence on the validity of the internal cavity of the specified size. The authors, at least, should provide an explanation on how to validate their model using the experimental investigation.
This manuscript has potential to advance the understanding of micellar systems, but revisions are required. The theoretical framework is creative but needs clearer validation pathways and more evidence to support its assumptions.
Author Response
The manuscript presents a novel theoretical model for ionic surfactant micellization, introducing the idea that micelles adopt a fullerene-like structure with a central cavity. It integrates concepts from quantum mechanics, symmetry, and chaos theory to reinterpret micelle dynamics and structural features at the nanoscale and it is a valuable piece of work to be published in Colloids and Interfaces. However, while the authors aim to resolve inconsistencies in classical models, the proposed framework is heavily reliant on assumptions and lacks sufficient experimental evidence to validate its claims. I suggest some revisions to clarify the theoretical foundation better. Additionally, the limitations of the proposed model should be explicitly acknowledged until clear experimental validation is available.
Answer: We thank dear Reviewer for his time and favorable attitude towards our manuscript. We tried to take into account all the reviewer's comments and explain that this work is not based only on the assumptions (although in our opinion this is also very important). Not so long ago (2022) we have published our previous manuscript "Morphology of ionic micelles as studied by numerical solution of Poisson equation" by O. Zueva, V. Rukhlov, Y. Zuev in ACS Omega (https://doi.org/10.1021/acsomega.1c06665) on the same subject related to ionic surfactant micellization. This computational-theoretical article was based on the previously obtained experimental results. Working on that article, in the available literature data on ionic surfactant micellization we revealed the existence of large number of inconsistencies and uncertainties, including even the notions and determination of micelle sizes. We concluded that the existence of partially contradictory classical approaches to the description of micellization, based on the quasi-chemical approximation or on the principles of nucleation theory, requires serious revision, since the formation of supramolecular structures cannot be reduced to either chemical reactions or crystallization. Now we try to find explanations of the contradictions that arose, using an independent approach and considering the formation of supramolecular structures based on the principles operating at the nanoscale.
The use of principles operating at the nanoscale explained the micelle structure and the diversity of micelle properties (solid in the radial direction and liquid-like in the perpendicular ones). Moreover, only within the framework of new concepts we can understand why a kinetically nonequilibrium system at the nanoscale is found in thermodynamic equilibrium at the macroscale. It is precisely the possibility of explaining these facts that is the main proof of the correctness of the proposed model.
Dear Reviewer, we are understanding rather clearly that proposed by us the advanced view on micellization process is only the model, which tries to explain numerous inconsistencies and uncertainties of existing models. And we suppose that analyzing such complicated dynamical system as micelles of ionic surfactants, it will be useful also to take into consideration our alternative view, which can explain some of obscure facts.
My suggestion to improve this work is as following.
1- The sentence (line 75) “Only recently, an understanding has emerged that ‘quantum mechanics and quantum coherence play a central role in chemistry’, also defining basic functioning of biological structures”, is somewhat misleading. Quantum mechanics has been a cornerstone of chemistry for decades.
Answer: We completely agree with the Reviewer that “Quantum mechanics has been a cornerstone of chemistry for decades.” The sentence (line 75) we have cited from the article of famous scientist Seth Lloyd ([8], doi:10.1088/1742-6596/302/1/012037) emphasizes the importance of quantum coherence. To note the authorship, the phrase has been added to the text of the sentence (line81): “as noted by S. Lloyd in [8]”.
2- The use of the word “radical” in sentences like “The current classical concept of micelle structure, containing the long-chain hydrophobic radicals (alkanes of 8–18 C atoms) and charged head groups” (line 134) can be replaced with “alkyl group”, which is a more appropriate term for this context.
Answer: We agree. The corresponding change in the text has been made (line 141): “the current classical concept of micelle structure, containing the long-chain hydrophobic radicals alkyl groups (alkanes of with 8-18 C atoms) and charged head groups, can be formulated as follows”.
3- The assumption that “only face centers of fullerene-like structure may be the sites of optimal binding” (line 328) is not well-explained. Why are these sites optimal? This statement needs further elaboration. Similarly in line 341: “also allow us to assume the penetration of water into the upper hydrocarbon layers under hydrostatic water pressure.” The macroscopic pressure force does not fit properly into the microscopic framework of the study unless been clarified.
Answer:
The assumption that "only face centers of fullerene-like structure may be the sites of optimal binding " is based on intermolecular interactions and symmetry considerations. A phrase explaining this fact has been added to the manuscript text (after line 336): “The symmetric arrangement of introduced cosurfactant molecule is the result of symmetric compensation of intermolecular interactions in the systems formed from identical molecules, even these molecules are of two different types (surfactant and cosurfactant). As a result, cosurfactant molecule occupies place which is maximally distant from all nearest neighbors. Taking into account the symmetry considerations, this arrangement corresponds to face centers of formed spatial structure.”
We agree that the deflection of face surfaces under the action of hydrostatic (i.e., external) pressure, may be considered in more details. As a result, the corresponding phrase took the following form (after line 354): “The possible deflection of face surfaces of fullerene-like structure with radially rigid (will be explained in section 3.5.4) diverging hydrocarbon chains, between which the regions with a reduced density are formed, also allow us to assume the penetration of water into the upper hydrocarbon layers under hydrostatic external water pressure (Figure 3)”.
4- Some claims in the manuscript are difficult to evaluate objectively. For instance, the statement in line 375 lacks sufficient justification: “In particular, since the most stable, widespread and easily synthesized fullerene molecule is C60, one can assume that micelle formed by 60 surfactant ions is the most stable and widespread for surfactant self-organization near CMC.”
Answer: This assumption is based on the commonality of symmetry properties of our space. However, we point out that this is not a statement, but an assumption. A phrase explaining this fact has been added to the manuscript text (after line 392): This assumption is based on the commonality of symmetry properties of our space.
5- The manuscript relies on a key assumption regarding an aggregation number of 60. The reference supporting this value (Ref. [40]) should specify the relevant chapter, as the information is hard to locate in the cited book. Furthermore, this value represents typical aggregation number rather than a fixed value, and it can vary significantly under different conditions (please see, for example, https://doi.org/10.1016/j.cis.2012.08.003). So, it is difficult to accept this aggregation number as the foundation of the model. A more realistic approach would account for a polydisperse aggregation number, reflecting the variability typically observed in micellar systems.
Answer:
The manuscript indeed does rely on the assumption that the aggregation numbers of ions in a micelle are close to 60 (Ref.[40], Israelachvili, J. Soft and Biological Structures, Chapter 20, In: Intermolecular and Surface Forces; 3rd Edition; Academic Press: Amsterdam, 2011). At the same time, we do not reject the assumption of a polydisperse aggregation number of micelles. We only state that of all micelles, the most stable and, accordingly, long-lived ones are micelles with an aggregation number of 60 (and 70). The variability in aggregation numbers is inherent in the mechanism of micelle formation. According to our assumption, micelles with all kinds of aggregation numbers can be formed, but their lifetimes will be short in comparison with Nagg = 60. Thus, at any given time, micelles with different aggregation numbers are present in solution. Therefore, micellar solution will be characterized by a certain distribution of micelles by size. The average aggregation number is a macroscopic characteristic of micellar solution obtained by averaging the statistical distribution of all possible micelles by size. To emphasize once again the existence of micelles with different aggregation numbers, the following text was inserted into the manuscript (after line 393): “Note, that the probability of polydispersity in micelle aggregation number is not rejected. However, it is believed that of all micelles formed, the micelles with aggregation number of 60 are the most stable and, accordingly, the most long-living. The variability in aggregation number is inherent in the mechanism of micelle formation”.
6- Citations that include web addresses (lines 581, 594, and 646) should follow standard referencing practices. Please kindly replace direct links with numbered references in the bibliography.
Answer: This comment has been taken into account, the web addresses have been added to the list of references as [105], [106], [112].
7- The manuscript claims that odd aggregation numbers do not occur (line 417), but this contradicts findings in the literature, such as https://doi.org/10.1021/j100046a031. This inconsistency needs to be acknowledged.
Answer: The aggregation number of ions in micelle and the average aggregation number of ions in micelle are different concepts. Let us assume that solution mainly contains two types of micelles – with an aggregation number of 58 and 60, and their number is approximately equal. When averaging, it will seem that micellar solution can be characterized by an average aggregation number of 59, i.e., as a result of averaging, an odd number may well be obtained.
8- There is a lack of strong simulation or experimental evidence on the validity of the internal cavity of the specified size. The authors, at least, should provide an explanation on how to validate their model using the experimental investigation.
Answer: It should be noted that the existence of cavity is not the specific quantum effect. The initial concept of micelle as a monomolecular layer of surfactant ions closed on itself corresponds to radial arrangement of hydrocarbon chains [46]. Then the radial arrangement of alkyl chains was turned down according to very simple reason – all the terminal methyl groups of hydrocarbon chains cannot fit the space in one point. The proposed attempts to consider a cavity inside a micelle [42,100-103] were rejected as contradicting the common sense and classical conceptions. After the discovery of fullerene molecule in 1985, modern concepts fully allow for the presence of a cavity. It should also be noted that the size of a cavity inside the micelle aggregate, consisting of 2520 atoms, is even 1.25 times smaller than that of the C60 fullerene molecule, and its volume is 2 times smaller than the cavity volume of C60. Therefore, there is nothing unique in the existence of a cavity.
The use of principles, operating at the nanoscale, explained the micelle structure and the diversity of micelle properties (solid in the radial direction and liquid-like in the perpendicular ones), which the classical model cannot explain. Moreover, only within the framework of new concepts we can understand why a kinetically nonequilibrium system at the nanoscale is thermodynamically in equilibrium at the macroscale. It is precisely the possibility of explaining these facts that is the main proof of the correctness of the proposed model.
------This manuscript has potential to advance the understanding of micellar systems, but revisions are required. The theoretical framework is creative but needs clearer validation pathways and more evidence to support its assumptions.
Answer:
Dear Reviewer, we thank you for your time spent for our manuscript, favorable attitude towards our manuscript, and your useful comments which we tried to take into account in its revised version.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe review paper entitled "Nanosized being of ionic surfactant micelles: an advanced view on micellization process" is interesting with some new findings. Nevertheless, major points should be addressed before publication.
- Introduction should clarify the differences between ionic surfactants and non-ionic surfactants. The effects on CMC need more details.
- Figure 2 needs a revision since the current figure seems to be one kind of protein virus.
- Section 3.3 should add the method to determine aggregation number in more details.
- Since anionic surfactant SDS is described in detail, cationic surfactant such as CTAB should be also mentioned.
- Solubilization of organic compounds with various application should be added.
Some example should be refered: Environmental Research 2022, 210, 112943; Langmuir 2024, 40, 26, 13573–13582
- Conclusions should be re-written to again emphasize the new findings in this review
Comments on the Quality of English LanguageEnglish of the manuscript should be improved by native speaker or professional editing service.
Author Response
The review paper entitled "Nanosized being of ionic surfactant micelles: an advanced view on micellization process" is interesting with some new findings. Nevertheless, major points should be addressed before publication.
Answer: We thank dear Reviewer for his time and favorable attitude towards our manuscript. We have tried to take into account all the reviewer's comments
1--- Introduction should clarify the differences between ionic surfactants and non-ionic surfactants. The effects on CMC need more details.
Answer: To clarify the differences between ionic and nonionic surfactants, the following text has been added to the introduction (after line 55): “Despite the existence of common properties of ionic micelles and nonionic associates at the macroscale, at the nanoscale, there is a sharp difference in the properties of ionic micelles comparing with conventional conceptions, which is manifested in the discrepancy between the sizes, driving forces, electric fields and types of kinetic units. The presence of ions stipulating the existence of ionic processes leads to the difference in kinetic processes occurring in solutions.” The effects of CMC were not studied in the manuscript, since only micellar solutions were considered.
2--- Figure 2 needs a revision since the current figure seems to be one kind of protein virus.
Answer: The uniformity of the symmetry properties of our space leads to the uniformity of forms of existence of matter on different scales. Therefore, the idea embedded in Figure 2 can be used to create a schematic representation of micelle. Any clarification of this structure will first of all require information on the specific type of head groups, which will inevitably lead to a loss of generality in the drawing.
3--- Section 3.3 should add the method to determine aggregation number in more details.
Answer: Our advanced model used the key assumption that the aggregation number of ions in a micelle is close to 60. At the same time, we do not reject the assumption of a polydisperse aggregation number of micelles. We only state that of all micelles, the most stable and, accordingly, long-lived ones are micelles with an aggregation number of 60 (and 70). The variability in aggregation numbers is inherent in the mechanism of micelle formation. According to our assumption, micelles with all kinds of aggregation numbers can be formed, but their lifetimes will be short in comparison with Nagg = 60. Thus, at any given time, micelles with different aggregation numbers are present in solution. Therefore, micellar solution will be characterized by a certain distribution of micelles by size. The average aggregation number is a macroscopic characteristic of micellar solution obtained by averaging the statistical distribution of all possible micelles by size. To emphasize once again the existence of micelles with different aggregation numbers, the following text was inserted into the manuscript (after line 393): “Note, that the probability of polydispersity in micelle aggregation number is not rejected. However, it is believed that of all micelles formed, the micelles with aggregation number of 60 are the most stable and, accordingly, the most long-living. The variability in aggregation number is inherent in the mechanism of micelle formation”.
4--- Since anionic surfactant SDS is described in detail, cationic surfactant such as CTAB should be also mentioned.
Answer: To emphasize the common structure and properties of anionic and cationic surfactants, the following text has been added to the manuscript in places (after line 146): The structure of hydrocarbon core is the same for anionic and cationic surfactants, and (after line 152) (positive for cationic surfactants and negative for anionic ones).
5--- Solubilization of organic compounds with various application should be added. Some example should be refered: Environmental Research 2022, 210, 112943; Langmuir 2024, 40, 26, 13573–13582
Answer: Solubilization of organic substances by micelles is the most important natural and technological property of micellar solutions. Therefore, issues related to solubilization require separate detailed consideration and do not fit into the scope of this article, which is already too large. A separate article is planned to be devoted to the description of solubilization mechanisms.
6--- Conclusions should be re-written to again emphasize the new findings in this review
Answer: The following text has been added into conclusions (after line 782): “The employment of principles operating at the nanoscale help to explain micelle structure and diversity of micelle properties (solid in the radial direction and liquid-like in the perpendicular ones), which cannot be explained by classical models. Moreover, only within the framework of new conceptions one can understand why a kinetically nonequilibrium system at the nanoscale is thermodynamically balanced at the macroscale.”.
Dear Reviewer, we thank you for your time spent for our manuscript, favorable attitude towards our manuscript, and your useful comments which we tried to take into account in its revised version.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript proposes advanced models for the micellization and micelle structure of ionic surfactants.
It is not clear whether the proposed models have been reported in the literature and here reviewed by the authors or the proposed models represent some assumptions made by the authors.
The manuscript is presented as a review. But it seems that the authors are expressing some opinions regarding novel models for micelles.
Actually, are there some experimental evidences for the models expressed by the authors as fullerene-like structure for micelles? Which are the experimental evidences supporting all proposed models for micelles.
Moreover, the abstract starts with the sentence " An advanced model of ionic surfactant micellization has been developed", which is not typical for a review manuscript
Moreover, it is not clear which are the experimental evidences supporting the proposed micelle models.
As regards Fullerene-like models for micelles, I have not find out any experimental or simulation work in the literature. Moreover, by checking the bibliography of the manuscript, I have not find out any citation from the authors and the cited papers deal with some secondary aspects but not with the description of the models. Is this model applicable to all ionic surfactants? How the hydrophobic tails of each surfactant are positioned in the fullerene-like model? Which is the interaction of surfactant and water according to this model?
Some links to webpages can be found in the manuscript but not cited in the bibliography. Some citations are in Russian language and not accessible.
Author Response
The manuscript proposes advanced models for the micellization and micelle structure of ionic surfactants.
Answer: We thank dear Reviewer for his time and favorable attitude towards our manuscript. We have tried to take into account all the reviewer's comments
1---It is not clear whether the proposed models have been reported in the literature and here reviewed by the authors or the proposed models represent some assumptions made by the authors. The manuscript is presented as a review. But it seems that the authors are expressing some opinions regarding novel models for micelles.
Answer: The manuscript is indeed presented as a review rather than a research article, since it examines the structural features and basic properties of micelles from the viewpoint of both classical and nanoscale concepts. As applied to micelles, the nanoscale concepts have not been assessed previously. Most of non-answered questions were raised in our recent previous manuscript "Morphology of ionic micelles as studied by numerical solution of Poisson equation" by O. Zueva, V. Rukhlov, Y. Zuev in ACS Omega (https://doi.org/10.1021/acsomega.1c06665) which is actively used as a refer in the present manuscript.
2---Actually, are there some experimental evidences for the models expressed by the authors as fullerene-like structure for micelles? Which are the experimental evidences supporting all proposed models for micelles. Moreover, it is not clear which are the experimental evidences supporting the proposed micelle models.
Answer: To clarify this issue, text was added to the conclusions (after line 782): “The employment of principles operating at the nanoscale help to explain micelle structure and diversity of micelle properties (solid in the radial direction and liquid-like in the perpendicular ones), which cannot be explained by classical models. Moreover, only within the framework of new conceptions one can understand why a kinetically nonequilibrium system at the nanoscale is thermodynamically balanced at the macroscale”.
3---Moreover, the abstract starts with the sentence " An advanced model of ionic surfactant micellization has been developed", which is not typical for a review manuscript
Answer: The proposed work is conceptual in nature and does not fit the standard forms and generally accepted structure of articles.
4---As regards Fullerene-like models for micelles, I have not find out any experimental or simulation work in the literature. Moreover, by checking the bibliography of the manuscript, I have not find out any citation from the authors and the cited papers deal with some secondary aspects but not with the description of the models. Is this model applicable to all ionic surfactants?
Answer: Not so long ago (2022) we have published our previous manuscript "Morphology of ionic micelles as studied by numerical solution of Poisson equation" by O. Zueva, V. Rukhlov, Y. Zuev in ACS Omega (https://doi.org/10.1021/acsomega.1c06665) on the same subject related to ionic surfactant micellization. This computational-theoretical article was based on the previously obtained experimental results. Working on that article, in the available literature data on ionic surfactant micellization we fined the existence of large number of inconsistencies and uncertainties, including even notions and determination of micelle sizes. We concluded that the existence of partially contradictory classical approaches to the description of micellization, based on the quasi-chemical approximation or on the principles of nucleation theory, requires serious revision, since the formation of supramolecular structures cannot be reduced to either chemical reactions or crystallization. We tried to find explanations of the contradictions that arose, using an independent approach and considering the formation of supramolecular structures based on the principles operating at the nanoscale. Our model is applicable to all ionic surfactants. We emphasize this point by adding the following text to the manuscript in two places (after line 146): The structure of hydrocarbon core is the same for anionic and cationic surfactants, and (after line 152) (positive for cationic surfactants and negative for anionic ones).
5--- How the hydrophobic tails of each surfactant are positioned in the fullerene-like model?
Answer: The principle of the identity of indiscernibles permits very high degree of symmetry for spherical micelles and the identity of spatial arrangement of hydrocarbon chains in such micelles, which can be realized only in the case of their radial arrangement without any bending of hydrocarbon chains. To clarify this issue, text has been added (after line 539): “So, inside the core, the identical surfactant hydrocarbon chains are located radially. Outside hydrocarbon core the surfactant ions can differ in their size and charge of head groups due to association with counterions or its absence. Since the association/dissociation processes are fast-flowing, upon the averaging micelles become symmetrical.”
6---Which is the interaction of surfactant and water according to this model?
Answer: We can conclude that aqueous pseudophase around micelle captures not only the Helmholtz-Stern layer, but the significant part of shell layer containing surfactant head groups and also some regions geometrically corresponding to hydrocarbon core. The possible deflection of face surfaces of fullerene-like structure with radially rigid diverging hydrocarbon chains between which regions with a reduced density are formed, allow us to assume the penetration of water into the upper hydrocarbon layers under external water pressure (Figure 3).
7---Some links to webpages can be found in the manuscript but not cited in the bibliography. Some citations are in Russian language and not accessible.
Answer: This comment has been taken into account, the web addresses have been added to the list of references as [105], [106], [112].
Dear Reviewer, we thank you for your time spent for our manuscript and your useful comments which we tried to take into account in its revised version.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors try to revise manuscript.
Some parts were improved but some one are not significant.
The authors did not address all my comments.
- The effects on CMC needs study because CMC is very important factor.
- Figure 2 still needs a revision since the current figure seems to be one kind of protein virus.
- Solubilization of organic compounds with various application should be added. Some example should be refered: Environmental Research 2022, 210, 112943.
- Cationic surfactant such as CTAB should be studied and compared with SDS.
Comments on the Quality of English LanguageNeed to be improved
Author Response
The authors try to revise manuscript. Some parts were improved but some one are not significant. The authors did not address all my comments.
Answer: We thank dear Reviewer for his time and favorable attitude towards our manuscript. We have tried to take into account all the reviewer's comments.
---- The effects on CMC needs study because CMC is very important factor.
Answer: Despite the fact that manuscript considers only surfactant micellar state in aqueous solutions, some conclusions about association/dissociation processes can indeed be made based on the non-classical behavior of micellar solutions near the Kraft point. An additional reference [100] was added: [100, Yu.F. Zuev, I.V. Lunev, A.N. Turanov, and O.S. Zueva. Micellization of sodium dodecyl sulfate in the vicinity of Krafft point: an NMR and dielectric spectroscopy study. Russ. Chem. Bull., 2024, Vol. 73, pp. 529—535. https://doi.org/10.1007/s11172-024-4162-5. New text fragment is inserted after the line 529: “Despite the fact that manuscript considers only surfactant micellar state in aqueous solutions, some conclusions about association/dissociation processes can also be made based on the non-classical behavior of micellar solutions near the Kraft point. In [100] it is noted that the Kraft point, which characterizes the transition temperature from surfactant solution to the onset of micellization and vice versa, differs significantly depending on temperature change direction. In particular, in SDS solutions the micellization starts after increase of temperature to 18 °C. Nevertheless, under decrease in temperature surfactant molecules retain micellar state down to 10 °C. Such discrepancy can be explained by micelles disintegration not to a monomolecular state, but to a significant extent to dimers, which are easier to reunite in association/dissociation processes”.
---- Figure 2 still needs a revision since the current figure seems to be one kind of protein virus.
Answer: Figure 2 is not of one kind of protein virus. Indeed, the popular description of virus is very far off real virus image (let me to make such conclusion since all my scientific way was located in molecular biophysics). It is only also a model, depicting its structural morphology – the presence of core and protective shell. The uniformity of the symmetry properties of our space leads to the uniformity of many forms of existence of matter on different space scales. Therefore, the idea embedded in Figure 2 is used to show schematic representation of micelle – the existence of spherical core and the shell. We tried to make different drawings, but this one turned out to be the most clearly depicting the micelle structure.
---- Solubilization of organic compounds with various application should be added. Some example should be refered: [T.D. Dinh, M.N. Phan, D.T. Nguyen, T.M.D. Le, A.K. Nadda, A.L. Srivastav, T.N.M. Pham, T.D. Pham. Removal of beta-lactam antibiotic in water environment by adsorption technique using cationic surfactant functionalized nanosilica rice husk. Environmental Research 2022, 210, 112943. https://doi.org/10.1016/j.envres.2022.112943]
Answer: Sorry, but our present work is not of the application aim. Nevertheless, according to Your kind recommendation we have inserted the corresponding text fragment with ref. [117] after the line 741: ”The solubilization of organic substances by micelles is one of the most important technological properties of micellar solutions. In particular, the removal of organic pollutants is of great importance in environmental research [117, T.D. Dinh, M.N. Phan, D.T. Nguyen, T.M.D. Le, A.K. Nadda, A.L. Srivastav, T.N.M. Pham, T.D. Pham. Removal of beta-lactam antibiotic in water environment by adsorption technique using cationic surfactant functionalized nanosilica rice husk. Environmental Research 2022, 210, 112943. https://doi.org/10.1016/j.envres.2022.112943]”.
---- Cationic surfactant such as CTAB should be studied and compared with SDS.
Answer: Text is inserted after the line 626: “Similar considerations allow us to calculate the size of micellar particle of cationic surfactant cetriltrimethylammonium bromide (CTAB), which has chemical formula CH3(CH2)15N(CH3)3Br. Taking into account the cavity of the same value, the radius of hydrocarbon core is equal to 2.24 nm. To estimate the size of CTAB head group, we can use the data from [26], which indicates its volume as 0.1023 nm3. Assuming a spheroidal shape of head group, the corresponding calculations let us estimate the diameter of CTAB head group as 0.58 nm. Thus, radius of CTAB micelle can be estimated as 2.82 nm. Unfortunately, the experimental data on the size of CTAB micelles, for example [82,113], are no less contradictory than the data on SDS, primarily due to some nonsphericity of micelles in the range of concentrations studied.”
Dear Reviewer, we thank you for your time spent for our manuscript, favorable attitude towards our manuscript, and your useful comments which we tried to take into account in its revised version.
Reviewer 3 Report
Comments and Suggestions for AuthorsI have read the authors answers and my main concerns about the manuscript is that I do not consider it as a review articles. Actually, the authors did not review the existing scientific literature but they expand their speculative approach on the base of the results previously published (Morphology of ionic micelles as studied by numerical solution of Poisson equation" by O. Zueva, V. Rukhlov, Y. Zuev in ACS Omega (https://doi.org/10.1021/acsomega.1c06665). Maybe, the manuscript can be included as a research article but the speculative approach must be highlighted and stressed in every consistent part of the manuscript. Moreover, limitations and the needs of experimental confirmations for the proposed models should be clearly specified. Experimental and/or simulation data will be helpful for the manuscript. The manuscript therefore requires additional revisions and improvements before publication.
Author Response
I have read the authors answers and my main concerns about the manuscript is that I do not consider it as a review articles. Actually, the authors did not review the existing scientific literature but they expand their speculative approach on the base of the results previously published (Morphology of ionic micelles as studied by numerical solution of Poisson equation" by O. Zueva, V. Rukhlov, Y. Zuev in ACS Omega (https://doi.org/10.1021/acsomega.1c06665). Maybe, the manuscript can be included as a research article but the speculative approach must be highlighted and stressed in every consistent part of the manuscript. Moreover, limitations and the needs of experimental confirmations for the proposed models should be clearly specified. Experimental and/or simulation data will be helpful for the manuscript. The manuscript therefore requires additional revisions and improvements before publication.
We thank dear Reviewer for his time and favorable attitude towards our manuscript. We have tried to take into account all the reviewer's comments.
Answer: We agree with the reviewer that the material we have presented is not a full-fledged review, since it contains many new assumptions and conclusions. In this paper, existing classical concepts of micellization are revised based on nanoscale concepts. Moreover, we did not aim to write a review paper. We simply wanted to show that the use of nanoscale concepts eliminates many inconsistencies in the classical theory, at that the advanced model proposes the same macroscopic properties of micelles as the classical one but modifies the structural characteristics of micelles at the nanoscale. Taking into account the reviewer's wishes, we replaced the term Review by the term Article in the article classification title. This is absolutely not significant for us.
The text of manuscript is structured in such a way as to emphasize the similarities and differences between the models. The existing experimental data can be considered as experimental confirmation of our model, since they can be interpreted from the standpoint of both models. To emphasize this point, the text fragment is inserted in the conclusion after line 808: “Thus, the existing experimental data can be interpreted from the standpoint of both models, considering them as experimental confirmation of our reasoning.”
Additional indirect experimental confirmation can be provided by our experimental work [100, Yu.F. Zuev, I.V. Lunev, A.N. Turanov, and O.S. Zueva. Micellization of sodium dodecyl sulfate in the vicinity of Krafft point: an NMR and dielectric spectroscopy study. Russ. Chem. Bull., 2024, 73, 529—535. https://doi.org/10.1007/s11172-024-4162-5 ], which we refer to in the text after line 529: “Despite the fact that manuscript considers only surfactant micellar state in aqueous solutions, some conclusions about association/dissociation processes can also be made based on the non-classical behavior of micellar solutions near the Kraft point. In [100] it is noted that the Kraft point, which characterizes the transition temperature from surfactant solution to the onset of micellization and vice versa, differs significantly depending on temperature change direction. In particular, in SDS solutions the micellization starts after increase of temperature to 18 °C. Nevertheless, under decrease in temperature surfactant molecules retain micellar state down to 10 °C. Such discrepancy can be explained by micelles disintegration not to a monomolecular state, but to a significant extent to dimers, which are easier to reunite in association/dissociation processes”.
Dear Reviewer, we thank you for your time spent for our manuscript, favorable attitude towards our manuscript, and your useful comments which we tried to take into account in its revised version.
Round 3
Reviewer 2 Report
Comments and Suggestions for AuthorsThe revised manuscript second version is significantly improved by the author that can be accepted in current form.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe reviewer appreciates the revisions made by the authors on the manuscript. However, as reported in my previous comment "limitations of the proposed advanced micellization models and the needs of experimental confirmations for them should be clearly specified" in the text.
Moreover, since the authors, as suggested, changed the manuscript from "review" to "article", it should be better specified in the manuscript that the proposed advanced models are assumptions of the authors and they do not have experimental confirmation until now, despite the the discussed theoretical argumentations. The proposed advanced models that are assumptions from the authors should be better connected to the traditional models, especially in the section 3.
