## 4 Conclusions  
The interaction between Pluronic F-127 and hydrophilic silica nanoparticles leads to the formation of stable complexes (copolymer-decorated nanoparticles) through hydrogen bonding between the oxyethylene groups of the copolymer and the non-dissociated silanol groups on the surface of the silica nanoparticles. The formation of these complexes favors the transport of the silica nanoparticles, which have poor interfacial activity, to the water-vapor interface and aids in their attachment.  
The results obtained indicate that the adsorption of copolymer-decorated nanoparticles at the water-vapor interface does not lead to noticeable differences from the interfacial properties of Pluronic F-127 in the same concentration range, and only a shift in them is found, depending on the particle concentration. In fact, the density of the Pluronic F-127 shell determines the interfacial tension due to its effect on the reorganization of the Pluronic F-127 molecules at the interface. The same idea can explain the dependence of the interfacial dilational elastic modulus on the concentration of Pluronic F-127 and silica nanoparticles. In fact, particles at the liquid-vapor interface behave as simple obstacles, and when the concentration of Pluronic F-127 becomes high enough to overcome the hindrance induced by the particles, the interfacial behavior becomes reminiscent of that corresponding to bare Pluronic F-127 solutions. This means that the modification of particles with Pluronic F-127 opens interesting avenues for tuning the mechanical performance of liquid-vapor interfaces with a decisive impact on the interfacial stability, and for applications of particle-laden interfaces in the stabilization of dispersed systems. In particular, since this work focuses on water-vapor interfaces, the results can be used to understand the most fundamental physicochemical principles underlying the stabilization of particle-stabilized foams.  
Conceptualization, R.G.R. and E.G.; methodology, C.C. and A.R.-B.; software, C.C. and E.G.; validation, F.O., R.G.R. and E.G.; formal analysis, C.C. and E.G.; investigation, C.C., A.R.-B., F.O., R.G.R. and E.G.; resources, F.O. and R.G.R.; data curation, C.C. and E.G.; writing--original draft preparation, E.G.; writing--review and editing, C.C., F.O., R.G.R. and E.G.; visualization, C.C. and E.G.; supervision, E.G.; project administration, E.G.; funding acquisition, F.O., R.G.R. and E.G. All authors have read and agreed to the published version of the manuscript.  
This work was funded by MICIN (Spain) under grant PID2019-106557 GB-C21, and by the E.U. within the framework of the European Innovative Training Network-Marie Sklodowska-Curie Action NanoPalnt (grant agreement 955612).  
Not applicable.  
Data Availability Statement: Data are available upon reasonable request.  
The Centro de Espectroscopia y Correlacion of the Universidad Complutense de Madrid is acknowledged for the use of their facilities.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.