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Capítuldo 5 confidencial pendiente de patente. Tesis completa 159 p. Tesis censurada 143, [ES]Las superficies expuestas al ambiente presentan una gran tendencia a atraer suciedad. Teniendo en cuenta que son éstas las que definen la mayor parte de las propiedades de los materiales, tanto la presencia como la acumulación de suciedad suponen un impacto negativo en numerosas aplicaciones ya que pueden generar importantes riesgos para la seguridad y la salud, así como, afectar negativamente al rendimiento, requiriendo costosas operaciones de mantenimiento. En los últimos años, la industria ha mostrado un gran interés en el desarrollo de soluciones capaces de preservar limpias las superficies. Tradicionalmente, las superficies repelentes se han obtenido mediante el efecto de la superhidrofobicidad. Sin embargo, su ineficacia para repeler líquidos de baja energía superficial y la fragilidad de ciertas micro/nanoestructuras necesarias pueden limitar su aplicación. En este contexto, el desarrollo de recubrimientos omnifóbicos de baja adhesión puede aportar numerosos beneficios en distintas aplicaciones de sectores muy diversos. Esta tesis persigue desarrollar nuevas estrategias para la obtención de superficies repelentes, focalizando el trabajo en alcanzar soluciones robustas con buenas prestaciones de durabilidad que sean capaces de responder a varias fuentes de contaminación simultáneamente. Para ello, el potencial que ofrece la nanotecnología se utiliza desde dos aproximaciones diferentes: a través de la estructuración superficial ymediante la incorporación de nanoobjetos como vectores para introducir nuevas funcionalidades, siendo el objetivo final desarrollar superficies omnifóbicas con propiedades diseñadas a medida que den respuesta a las necesidades de la industria.

This paper explores how Biologically Inspired Design (BID) can be applied in the development of medical devices through a concrete case study. Nature has been developing, over the last 3.8 billion years, the most efficient mechanisms to fulfil a function and overcome challenges. Based on this giant innovation database, BID has received an exponential increase of interest since the 1950s and has led to innovative solutions in a vast variety of fields. The present study is motivated by a medical device which should be designed for insertion in a cavity, followed by a significant expansion inside the cavity. Once expanded, the device should be able to radiate light for disinfection purposes, while simultaneously allowing air replacement in the cavity. Finally, the device should contract to its original size before being extracted from the cavity. In order to propose radically new ideas for designing such a device, BID is applied to a range of functions namely i) how to expand an object after insertion in a cavity, ii) how to promote air circulation in the cavity, iii) how to radiate light to all surfaces in the cavity and finally iv) how to contract the object again. This paper presents and discusses the BID process as well as the outcomes of this study. 25 biological strategies have been identified throughout the project, 7 ideas were generated and 4 more detailed concepts and physical mock-ups emerged from these ideas. 2 of them were considered interesting for further development, which indicates a good efficacy of the process. The whole study lasted 32 working days, suggesting a high efficiency of the BID process.

The use of electricity is so pervasive that life without it is unimaginable today. The scope of electricity is even widening to encompass wearables and draperies in domestic and professional surroundings. The typical way of conducting electricity is through metallic wires and conduits, which often are integrated permanently into engineered products. This means that we have more and more products with mixed materials that are difficult to recycle, thereby creating a major bottleneck towards the achievement of sustainable urban and rural environments. If electricity could be conducted in another way, new design options would become possible. The bioworld offers ways for conducting electricity without metallic interconnects. Examples range from electric discharges by electric eels to electrolocation by fish to bacterial protein networks that conduct electrons. A review of electrical conduction mechanisms in the bioworld suugests the feasibility of incorporating the underlying bioworld principles in engineered products.

A controllable magnetochromic elastomer is developed by dissolving magnetic nanoparticles (MNPs) in poly(ethylene glycol)-200 (PEG-200) and emulsifying the solution in polydimethylsiloxane (PDMS) using a high-shear Speedmixer. The MNPs are aligned in order along the direction of the externally applied magnetic field, causing the material to become transparent and realizing a switch on/off function. Both particle size and size distribution were observed to affect magnetochromic response, and use of an ultrasonication bath was shown to prohibit MNP agglomerations. In addition, the surfactant surface-modified MNPs synthesized via co-precipitation were shown to possess both a smaller primary size and a narrower size distribution compared to non-treated commercial MNPs, leading to improved MNP dispersion stability in PEG-200. The optimized silicone elastomer—with 40 parts per hundred rubber (phr) PEG-200 and 3 wt% MNPs modified by citric acid surfactant—exhibits instantaneous and reversible color change when exposed to an external magnetic field. The color changing efficiency and fast response time of the magnetochromic elastomer developed here are suited to a variety of color tuning applications: e.g., bio-sensors and anticounterfeiting labels.

Este trabajo tiene como objetivo diseñar nuevos materiales termoeléctricos (TE) híbridos mediante infiltración en fase vapor (VPI). El origen del VPI reside en la técnica de deposición de capas atómicas o ALD y se basa en el mismo montaje instrumental. Sin embargo, no se aplica a sustratos sólidos sino a sustratos poliméricos, lo que hace que los precursores no sólo se unan a la superficie como en el caso del ALD, sino que también se difundan en el polímero a través de la disolución vapor-sólido. Tras la difusión y la unión, se genera un material híbrido inorgánico-orgánico dentro del polímero. La extensión del área infiltrada en la masa del polímero puede modificarse cambiando los tiempos de exposición, además de poder variar también en función de la difusividad de los precursores dentro del polímero. Por lo que depende tanto de las características del polímero como del precursor. Estas diferencias clave hacen que el VPI sirva para la fabricación de nuevos materiales híbridos. En el presente trabajo hemos creado un nuevo conjunto de materiales híbridos con interfaces orgánicas/inorgánicas unidas covalentemente mediante la hibridación del material inorgánico TE Bi2S3 con los polímeros semiconductores PEDOT: PSS y PANI. El proceso de hibridación se monitorizó in-situ con una microbalanza de cristal de cuarzo (QCM). La monitorización permitió estudiar el proceso de VPI en detalle y controlar cuantitativamente la carga de precursores inorgánicos como el BiCl3 y el H2S en los polímeros, permitiendo así un grado extra de flexibilidad para la mejora de las propiedades del material. La composición química y la estructura de los materiales híbridos resultantes tras varias etapas de infiltración se analizaron con microscopía electrónica de transmisión de alta resolución (HRTEM) y espectroscopia de rayos X de dispersión de energía (EDX). Los resultados mostraron que el VPI proporciona un alto grado de control sobre la distribución de las fases inorgánicas y la composición gen, The aim of the present work is to design new hybrid thermoelectric (TE) materials by vapor phase infiltration (VPI). VPI is a process which derives from atomic layer deposition (ALD) and bases on the same instrumental setup. However, it is not applied to solid substrates but to polymeric substrates, which causes that the precursors not only bind to the surface, but also diffuse into the polymer through vapor– solid dissolution. Upon diffusion and binding an inorganic–organic hybrid material is generated inside the bulk of the polymer. The extension of the infiltrated area into the bulk of the polymer can be modified by changing the exposure times, but it also can vary in dependence on the diffusivity of the precursors inside the polymer. Therefore, it is dependent on both the polymer and precursor characteristics. These key differences make VPI for the fabrication of new hybrid materials. In the present work we created such a new hybrid material set with covalently bound organic/inorganic interfaces by hybridization of the inorganic TE material Bi2S3 with the semiconducting polymers PEDOT: PSS and PANI. The hybridization process was monitored in-situ with a Quartz Crystal Microbalance (QCM). The monitoring allowed studying the VPI process in detail and quantitatively controlling the loading of inorganic precursors like BiCl3 and H2S into polymers bulk, thus allowing an extra degree of flexibility for tuning the material properties. The chemical composition and structure of the resulting hybrid materials upon various stages of infiltration was analyzed with high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDX). The results showed that VPI provides a high degree of control on the inorganic phase distribution and overall composition of the hybrids by tuning the process parameters such as temperature, penetrant pressure, and exposure time. The obtained results offer new solutions for the waste-heat-to-energy industry.

We report for the first time on a pulsed vapor phase copper-free azide-alkyne click reaction on ZnO by using the atomic layer deposition (ALD) process technology. This reproducible and fast method is based on an in situ two-step reaction consisting of sequential exposures of ZnO to propiolic acid and benzyl azide.