RT Dissertation/Thesis
T1 Development of new analysis methods for the study of molecular aggregation and adsorption
A1 Fernández Garrido, Pablo
K1 Aggregation
K1 Adsorption
K1 ITC
K1 Interfaces
AB Molecular aggregation processes as well as adsorption to interfacesbetween media of different polarity are necessary for many natural phenomena and industrial applications. Fromthe formation of cell membranes to the building of self-assembled materials, to the encapsulation of particles bycleaning products, these phenomena are based on the organized molecular self-assembly. There is a clearconnection between aggregation and adsorption processes, in such a way that they are very difficult to separate:usually, molecules with high affinity to interfaces between media of different polarity also have a clear ability to selforganizein the liquid phase. Given the importance of both processes, there is a large number of experimental(absorption/emission spectroscopy at different frequencies, particle or light scattering, electrical, magnetic,chemical, optical or mechanical properties, calorimetric measurements and a wide range of microscopytechniques) and computational techniques to address them. Yet, no experimental method is able to simultaneouslyasses both phenomena within the same experiment. On the other hand, the behavior of molecules in both phasesis often completely different. For many substances, solutions at almost negligible concentrations in the liquid phasemay lead to saturation at the interface. The main objective of the present project is to provide new analysis methodsfor the study of molecular aggregation and adsorption processes that make a qualitative difference compared withthe currently available methods. In particular, we propose to develop a new technique to simultaneously measurethe heat of adsorption to the liquid/air interface and the surface tension by modifying the sample cell of anisothermal titration calorimeter. As shown by several preliminary experiments, this will allow measuring a newproperty that can not be directly reached by any other method nowadays. Additionally, the proposed method willalso allow performing surface tension measurements through calorimetric titrations, without the need of preparing asolution for every measured concentration or investing time and effort in material clean-up. On the other hand, wehave developed models allowing to extract a large amount of information from these measurements in a singleexperiment, including properties such as the aggregate size, the Gibbs energies of aggregation and adsorption, theminimum area per molecule, the concentrations of free species and aggregate molecules in the liquid phase, andthe concentration at the interface. In addition to this new methodology, which is expected to be transferred forcommercial use, we dedicate a part of the project to the development of computational methods, both in modelfitting programs and in molecular dynamics simulations, as well as to studies of systems with different degree ofcomplexity, including from classical surfactants to mixtures of inorganic nanoparticles with the most abundantproteins in blood serum. The aim of these later studies, besides the interest of the systems themselves, is to seekthe limits of the developed methods.
YR 2021
FD 2021
LK http://hdl.handle.net/10347/27392
UL http://hdl.handle.net/10347/27392
LA eng
DS Minerva
RD 30 abr 2026