I apologize for the delay but as I received two very different evaluations of your revised manuscript by the original referees, I solicited the report from a third colleague. While the report by the second referee is very positive and requests only very minor (mostly language) changes, the other two referees are much more critical.

Overall, the original two referees agree that the manuscript has been improved; however, they and also the third have some major concerns on the novelty and importance of the current results for atmospheric science. I generally agree with their concerns; I rephrase and summarize the main concerns below.
Please address those and the detailed comments in the three referee reports in your further revision of the manuscript.

1) All three referees agree that the novelty of the current study in terms of our understanding of the role of surface partitioning on CCN is limited. The paper is very lengthy while it does not become clear what the innovative aspects of the study are at the current state of the field. The discussion and conclusions should be more concise and highlight the need of the consideration of surface partitioning and the conditions under which your findings are relevant in the atmosphere. The current discussion is rather vague and pretentious, given that the study is based on one ternary mixture and strongly dependent on the fit parameters. Some discussion of the relevance of this mixture and/or the distribution of similarly surface-active compounds throughout CCN distributions should be added to demonstrate in a more balanced way the general implications for atmospheric science rather than to limit the study to investigations that are primarily of technical interest.

2) The current study is heavily based on your previous study (Prisle et al., 2010) which is explained in detail throughout the manuscript. While there is, of course, generally no objection to apply such previously published framework in a follow-up study, the detailed description of this established framework results adds to the lack of focus.

3) Even though the manuscript was initially submitted more than two years ago, the referees and I have to evaluate it under the aspects of current knowledge and state-of-the-art in the field. While the idea of surface/bulk partitioning of surfactants on atmospheric aerosols might have been more innovative back then, it is much more established by now in the atmospheric chemistry community. In addition, some more advanced and refined approaches have been put forward, e.g. (Davies et al., 2019) that should be discussed to explain the observations in the current study (cf Report by Referee #1).

Dear Nonne,

Many thanks for revising the manuscript. However, some of the major concerns that were already raised in the previous referee reports remain. The manuscript is very lengthy and its conclusions are not clear. I hope that my comments (attachment) help to sharpen its focus and to highlight its novelty and potential relevance for atmospheric systems.
Given the limited discussion of general implications and the rather vague demonstration of substantial advances for understanding of physical and chemical processes, I will not accept this manuscript as a Research Article after revision but as a Technical Note.

Sincerely
Barbara Ervens

Dear Nonne,

many thanks for the final corrections and revision of your manuscript. I am happy to accept it for publication in ACP.
Sincerely,
Barbara