Seminars and Events

Seminars and Events

PhD Thesis


04 March 2020, 10:30 h. Salón de Actos

Advanced Force Spectroscopy Applications:
Three-Dimensional AFM and Single-Molecule Force Spectroscopy

Manuel Ralph Uhlig
ICMM, CSIC

Supervisor(s): Ricardo García

When it comes to the nanoscale, the Atomic Force Microscope (AFM) is one of the most widely used tools in science and technology. Among the plethora of available AFM modes, some of the most successful ones fall into the category of AFM Force Spectroscopy. Current activities and frontiers of the field are related to the speed and sensitivity limits of established force spectroscopy tools. More sophisticated techniques such as three-dimensional (3D)-AFM and high-speed AFM force spectroscopy have emerged recently to eventually overcome existing limitations. 3D-AFM has been developed as a versatile tool to study solid-liquid interfaces with atomic-scale resolution. High-Speed force spectroscopy has bridged the temporal gap between unbinding experiments and molecular dynamics simulations.
This PhD thesis is dedicated to address different aspects of these techniques in order to further improve the instrument s performance and to gain further insight into complex samples.

The thesis defense will be divided in two parts:

The first part focuses on the application of 3D-AFM to study the solid-liquid interface of hydrophobic materials immersed in ultrapure water. Among them a variety of layered materials including mono- and multilayer sheets of graphene and transition metal dichalcogenides, as well as pentacene thin-films. The images reveal a universally occurring structuring of the liquid in the vicinity of the surfaces. It is shown that the observations are related to the hydrophobicity of these surfaces and their interaction with airborne adsorbates.

The second part presents a study of the AFM cantilever dynamics in breaking intermolecular bonds by high-speed single-molecule force spectroscopy (SMFS). Experiments are performed on the biotin-avidin system that demonstrate deviations from the standard description of forced unbinding. By developing an analytical equation of motion for SMFS, the observations are explained in terms of cantilever dynamics occurring at high velocities. With the help of simulations, a general criterion is found for the accuracy range of Hooke s law. A correction factor is provided and applied to the experimental data to recover the intrinsic unbinding forces.





14 February 2020, 12:00 h. Salón de Actos

Clay-based hybrid nanoplatforms: preparation, characterization and evaluation of properties for controlled release of bioactive species

Ediana Paula Rebitski
Universidad Autonoma de Madrid

Supervisor(s): Dr. Pilar Aranda
Dr. Margarita Darder


This Doctoral Thesis is centered in the field of the nanostructured hybrid materials, and more specifically addresses the study of the so-called biohybrid materials resulting from the assembly of molecular and polymeric species of biological origin with inorganic substrates at the nanometer scale. The Thesis deals with the preparation and characterization of hybrid and biohybrid materials by intercalation of bioactive species in silicates of the type of clays and other related inorganic layered solids, and their integration into more complex systems such as bionanocomposites and nanoarchitectures, for application as controlled release systems of drugs and herbicides.





14 February 2020, 12:00 h. Facultad de Ciencias de la UAM - Módulo 8 - Sala de grados

Síntesis y Procesado de Materiales Carbonosos para la Fabricación de Sistemas Fotónicos

Luz Karime Gil-Herrera
ICMM

Supervisor(s): Cefe López Fernández y Alvaro Blanco Montes

Los cristales coloidales fotónicos (CCF) despiertan un gran interés no solo por su potencial de generar materiales con un gap fotónico completo, sino también, por el reto que a nivel sintético supone su fabricación. El autoensamblamiento de esferas coloidales monodispersas es la estrategia que típicamente se usa para la obtención de cristales de alta calidad. Así, esferas poliméricas o de sílice son empleadas como bloques de construcción de un CCF. Sin embargo, su baja estabilidad coloidal y/o térmica produce inconvenientes no solo en la obtención de estructuras ordenadas de calidad, sino que limitan el post procesamiento térmico que involucra el proceso. En este sentido las esferas carbonosas coloidales son prometedoras tanto por sus propiedades fisicoquímicas como por su relativa facilidad de fabricación. Por lo tanto, esta tesis tiene como objetivo demostrar la viabilidad y utilidad que tienen los materiales carbonosos para ser usados como plantilla en la fabricación de estructuras con aplicaciones en fotónica. Consecuentemente, se obtuvo un sistema fotónico de silicio utilizando ópalos carbonosos. Además, debido a la complejidad de las estructuras carbonosa, obtuvimos múltiples arquitecturas hibridas de Si-C o de Si poroso con propiedades fotónicas.
La aportación de esta tesis bajo el paraguas de la fabricación de cristales fotónicos, tiene la intención de proporcionar nuevos avances y mejoras en los materiales existentes, pero además pretende dar luces en otros campos de investigación en donde las arquitecturas generadas puedan ser puntos de partida o de inspiración.





30 January 2020, 12:00 h. Salón de Actos

Quantum dynamics in low-dimensional topological systems

Miguel Bello Gamboa


Supervisor(s): Gloria Platero








   

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