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The effective incorporation of (multi)functional oxides into next-generation flexible electronics systems requires novel fabrication technologies that enable the direct integration of crystalline oxide layers in them. Unfortunately, this is considerably challenging due to the thermal incompatibility between the crystallization temperatures of metal oxides (>600 degrees C) and the thermal stability of the flexible polymer substrates conventionally used (

This work reports the obtaining of lime-based grouts as repairing materials. Microsilica was added as pozzolanic additive to enhance the compressive strength of the hardened grouts. Sodium oleate, as water repellent admixture, and different superplasticizers were also incorporated to reduce the water absorption and to enhance the injectability of the grouts. Polycarboxylate ether (PCE), polynaphthalene sulfonate (PNS), melamine sulfonate (MMS) and polyacrylic acid (PA) were tested as plasticizing agents. Regarding the fluidity of the grouts, PCE was seen to improve the injectability, followed by PNS, MMS and PA. However, PCE addition was also accompanied by a severe delay in the setting time. The other three superplasticizers did not provoke significant delays in the hardening of the samples. The water contact angle underwent an increase pointing to an effective hydrophobization of the surface as a consequence of the water repellent admixture. The combination with PCE was the most effective in keeping the water repellency in comparison with the control sample (lime grout + oleate). MMS yielded high compressive strengths and durability of the mortars, in the face of freezing-thawing cycles, was enhanced.

This book collects the abstracts of the communications presented in the 5th Historic Mortars Conference (HMC 2019) organized by the Heritage, Materials & Environment (MIMED) Research Group of the Chemistry Department of the University of Navarra at the School of Sciences in Pamplona from 19 to 21 June 2019.

Actas revisadas por pares de los trabajos presentados en las VI Jornadas FICAL organizadas por el Grupo de Investigación MIMED del Departamento de Química de la Facultad de Ciencias, celebradas en la Universidad de Navarra del 28 al 30 de mayo de 2018.

El presente trabajo tiene como principal objetivo estudiar las interacciones que se producen cuando se adicionan separadamente dos superplastificantes (PNS –sulfonato de polinaftaleno- y LS –lignosulfonato-) a un conglomerante aéreo (cal aérea Cl 90-S) y a uno hidráulico formado por cal aérea a la que se le ha añadido metacaolín como material puzolánico, y los efectos que dichas adiciones tienen en las propiedades de los sistemas. Para la fabricación de los morteros, se empleó árido calcáreo. Adicionalmente, se efectuaron ensayos de durabilidad en morteros con la composición citada, sometiéndolos a ciclos de hielo-deshielo y a ataque con sulfatos. Aunque se realizaron algunas medidas con las pastas en estado fresco, la mayoría de los experimentos (resistencia a compresión y a flexión, TG-ATD, DRX, FTIR-ATR, porosimetría de intrusión de mercurio) se realizaron tras períodos de fraguado del mortero de 7, 28, 91, 182 y 365 días. Se detectaron fases silicatadas y silicoaluminatadas en los morteros estudiados, a pesar de que las experiencias se realizaron a temperatura ambiente y con un bajo porcentaje de material puzolánico (≤20 %). La presencia de LS impidió el proceso de carbonatación, lo que a su vez provocó un decrecimiento en los valores de resistencia mecánica cuando se trataba de morteros hidráulicos. Se observó asimismo una mayor porosidad y un mayor tamaño medio de poro en el caso de sistemas con LS. La durabilidad (ciclos hielo-deshielo) de los morteros mejoró notable tras la incorporación de metacaolín y empeoró tras la adición de LS (morteros hidráulicos). Los resultados del actual sistema fueron comparados con aquellos obtenidos en otro sistema en el que se empleó nanosílice como agente puzolánico.

Los morteros de relleno o inyección, especialmente destinados a reparación de cavidades y defectos de albañilería, deben fluir adecuadamente en estado fresco y combinar resistencia y durabilidad. Para conseguir algunas de estas características pueden utilizarse aditivos químicos: superplastificantes, para mejorar la fluidez; adiciones puzolánicas, para conseguir resistencias adecuadas en ambientes con limitado acceso de CO2 y una mejora de la durabilidad; e hidrofugantes, de manera que, sin perjudicar la permeabilidad de estos materiales al vapor de agua, se evite la penetración de agua por capilaridad mejorando la durabilidad. Sin embargo, en la mayor parte de los casos, toda la información disponible se circunscribe al efecto de un único aditivo, sin contemplar el posible efecto conjunto o incluso sinérgico de las combinaciones más interesantes de dos o más aditivos y/o adiciones puzolánicas. El estudio de las sinergias entre estos componentes ofrece posibilidades muy interesantes de avance científico-técnico. Precisamente este es el objetivo del trabajo: diseño de nuevos morteros de inyección de cal que puedan ser utilizados para la restauración del Patrimonio Edificado mediante combinación adecuada de aditivos superplastificantes (éteres de policarboxilato, condensados de naftaleno-formaldehído, sulfonato de melamina y ácido poliacrílico), hidrofugante (oleato sódico) y adiciones minerales puzolánicas (microsílice y metacaolín).

Resúmenes de las comunicacones presentadas a las VI Jornadas FICAL - Fórum Ibérico de la Cal celebradas en Pamplona del 28 al 30 de mayo de 2018, organizadas por el Grupo de Investaigación MIMED del Departamento de Química de la Facultad de Ciencias de la Universidad de Navarra.

NATURALEZA Y TIPOS DE CALES En función de la composición química y del mecanismo de fraguado de las cales, éstas se dividen en dos grandes grupos: - Cales aéreas: se componen principalmente de óxido o hidróxido de calcio, y endurecen lentamente al aire por la acción del dióxido de carbono atmosférico. - Cales hidráulicas: en su composición, además de óxidos e hidróxidos de calcio, aparecen silicatos y aluminatos cálcicos, por lo que tienen la capacidad de fraguar al ponerse en contacto con el agua.

Esta tesis doctoral demuestra que el depósito químico de disoluciones (Chemical Solution Deposition, CSD) es una técnica viable para la preparación de láminas delgadas sin plomo de (Bi0.5Na0.5)1-xBaxTiO3 (BNBT), con un control preciso de su composición y estructura cristalina. Un estudio de estos materiales llevado a cabo con técnicas avanzadas de caracterización composicional y estructural ha permitido situar la frontera de fase morfotrópica (Morphotropic Phase Boundary, MPB) de estas láminas, así como establecer un perfil estructural y composicional de las mismas. Por otro lado, se ha desarrollado una nueva ruta sintética en disolución para materiales basados en bismuto, basada en reacciones fotoquímicas inducidas por luz UV, que ha permitido reducir notablemente la temperatura de procesado de las láminas delgadas de BNBT.

A superplasticizing admixture of natural origin, lignosulfonate (LS), was incorporated to air lime mortars sometimes modified with a pozzolanic additive, metakaolin, to obtain a new range of repair mortars to be applied in Built Heritage. LS improved the flowability of the air lime samples and showed good slump retention over time: for example, after 150 minutes of the air lime pastes preparation, blends with LS lost only ca. 13% of the slump value. Experimental results showed that LS interfered with the carbonation due to its ability to form Ca2+ complexes. Adsorption isotherms and zeta potential measurements showed that LS was scarcely adsorbed onto lime and C-S-H particles. Due to its branchy structure, LS exhibited an adsorption mechanism leading to steric hindrance as the main responsible mechanism for avoiding flocculation. The presence of free LS molecules in the dispersion was seen to improve the plasticizing effect of this polymer. Flexural and compressive strengths as well as the durability in the face of freezing-thawing cycles of these mortars were also determined to assess the applicability of these repair mortars.

The potential of UV-light for the photochemical synthesis and stabilization of non-equilibrium crystalline phases in thin films is demonstrated for the beta-Bi2O3 polymorph. The pure beta-Bi2O3 phase is thermodynamically stable at high temperature (450-667 degrees C), which limits its applications in devices. Here, a tailored UV-absorbing bismuth(III)-N-methyldiethanolamine complex is selected as an ideal precursor for this phase, in order to induce under UV-light the formation of a -Bi-O-Bi- continuous network in the deposited layers and the further conversion into the beta-Bi2O3 polymorph at a temperature as low as 250 degrees C. The stabilization of the beta-Bi2O3 films is confirmed by their conductivity behavior and a thorough characterization of their crystal structure. This is also supported by their remarkable photocatalytic activity. Besides, this processing method has allowed us for the first time the preparation of beta-Bi2O3 films on flexible plastic substrates, which opens new opportunities for using these materials in potential applications not available until now (e.g., flexible photocatalytic reactors, self-cleaning surfaces or wearable antimicrobial fabrics). Therefore, photochemical solution deposition (PCSD) demonstrates to be not only an efficient approach for the low temperature processing of oxide films, but also an excellent alternative for the stabilization of metastable phases.

The obtaining of self-cleaning mortars is very interesting to apply them in Built Heritage. Atmospheric pollutants, mainly carbonaceous particles and gases like NOx and SO2 can lead to severe aesthetic and functional damages in artworks. In the case of mortars and renders, the use of photocatalysts -usually based on TiO2- can be worthy of consideration. Photocatalysts, after being activated by light, are able to oxidize pollutants avoiding their deposition onto building materials. In this work, different air lime mortars modified upon the addition of TiO2-based photocatalysts were obtained and studied. Photocatalysts can be incorporated in bulk and the changes in fresh state properties were studied as well as the effect of the presence of the photocatalysts on the pore structure and mechanical resistance. Finally, the photocatalytic efficiency of these materials was carried out by means of a NOx abatement test. Results showed that the presence of the photocatalysts had a positive impact on the preservation of the lime mortars characteristics.

This contribution dealt with the design of different air lime mortars and pastes by combining a nanostructured pozzolanic additive, nanosilica, and different dispersing agents, superplasticizers (two different polycarboxylate ethers (PCE), a polynaphthalene sulfonate-based polymer (PNS) and a lignosulfonate (LS)). In pure air lime systems, the highest effectiveness was shown by the PCE1, whereas the PNS was the less effective superplasticizer. In samples with nanosilica, the PCE1 was also the most effective superplasticizer. LS was seen to be effective at low dosages. In the presence of the pozzolanic additive, there was a high consumption of polycarboxylates. Nanosilica provided no “active” adsorption sites, resulting in a slight decrease of the zeta potential values. PCE1 showed low adsorbed amounts, better dispersing action and required lower dosage of plasticizing agent. There was a positive combination between lime mortars with nanosilica and polycarboxylates, which resulted in a mechanical strength improvement. Also the combined presence of nanosilica, for example, with PNS or with LS yielded better compressive strengths, being LS more effective than PNS: SEM images showed the better formation of C-S-H phases in LS-mortars.

Los morteros de cal presentan una interesante capacidad de admitir aditivos fotocatalíticos sin detrimento de otras características: se mantienen adecuadas resistencias, la estructura porosa no se modifica de forma sustancial y no hay cambios aparentes de color o brillo. El TiO2 dopado presenta sensibilidad mejorada hacia la luz solar y es una interesante vía de aplicación. Los recubrimientos activos son una manera muy prometedora de mejorar las prestaciones de autolimpieza de los morteros de cal. El uso de aditivos dispersantes y/o de medios de dispersión adecuados puede mejorar notablemente la eficacia fotocatalítica de los morteros de cal tratados.

A new range of repair lime mortars were obtained by using as superplasticizer a polynaphthalene sulfonate-based polymer (PNS) and metakaolin as pozzolanic addition. Adsorption isotherms showed that PNS exhibited a high affinity for air lime particles with 52.08 mg•g-1 as maximum sorption capacity in pure air lime media. Mathematical treatment of experimental data showed an optimal adjustment to a Freundlich model, in which interactions arising from multilayer adsorption are taken into account. The experimental results suggested a great interaction of PNS with air lime media (pure air lime or air lime with MK). Zeta potential curves of air lime systems titrated with PNS showed a larger zeta potential reduction, giving rise to a charge reversal, as a consequence of the high anionic charge density of this polymer (2.44 meq of anionic charge•g-1). A flat adsorption was proposed as the attachment model of this admixture, owing to its higher anionic charge density and to its linear shape. The electrostatic repulsion was then the main action mechanism to explain the PNS function. In the hardened state, the combination of PNS and MK resulted sometimes in moderate mechanical strength increases and in a clear enhancement of the durability in the face of freezing-thawing cycles

The photocatalytic activity of powdered TiO2 (75% anatase, 25% rutile) was tested after the incorporation of the additive in mortars of calcium aluminate cement. Two different CACs were used according to their chemical and mineralogical composition: one of the CAC was a high alumina cement (H-CAC, 70.9% of Al2O3) while the other one was a low alumina cement (L-CAC, 42.0% of Al2O3) with a large amount of ferrite. One batch of the prepared mortars was tested after being subjected to 28 days under a normal curing regime (20ºC and 95% RH). A second batch was tested after a curing regime of 60ºC and 100% RH (for 24 hours) and then 20ºC and 95% RH. This second curing regime intended to induce the conversion reaction, which is responsible for the formation of stable calcium aluminate hydrates at the expense of metastable hydrates. Different properties such as workability, setting time and compressive strength were determined in the tested mortars in order to study the influence of the TiO2 addition. The photocatalytic effect was assessed by means of the NOx abatement under UV irradiation. The TiO2-H-CAC mortars were found excellent systems to decrease NO2 concentrations in connection with the more abundant presence of aluminates. The better NO2 retention improved the NOx removal. An chemical interaction between ferrite and TiO2 was suggested to take place in the L-CAC mortars as evidenced by XRD, SEM, EDAX and zeta potential analyses. This interaction originated two new iron titanate phases, namely pseudobrookite and, to a lesser extent, ilmenite. The reduced band-gap energy of these compounds compared with that of TiO2 improved the photocatalytic efficiency of L-CAC samples in the visible spectrum, as proved by Methyl Orange degradation tests, conferring a self-cleaning ability to the TiO2-bearing iron-reach L-CAC under visible illumination.

The use of calcium aluminate cements to efficiently encapsulate hazardous wastes was reported. Specifically, the quick formation of a matrix of low porosity and high stability was intended. The reaction between phosphate groups and calcium aluminate cement was extremely important in this case. This work presents an acid-base reaction between phosphates present in the sludges from the automotive industry and calcium aluminate cement that yielded very inert and stable monolithic blocks of amorphous calcium phosphate (ACP). Two industrial sludges of different compositions were characterized and loaded in different ratios (from 10 to 50 wt.%). Setting times and compressive strengths were recorded to establish the feasibility of this method to achieve a good handling and a safe landfilling of these samples. Short solidification periods were found and leaching tests showed an excellent retention for toxic metals such as Zn, Ni, Cu, Cr and Mn and also for organic matter. Retentions over 99.9% for Zn and Mn were observed even for loadings as high as 50 wt.% of the wastes. The formation of ACP phase of low porosity and high stability accounted for the effective immobilization of the hazardous components of the wastes, as confirmed by X-ray diffraction and SEM-EDAX studies. Comparison with the performance of pure sodium hexametaphosphate-CAC mortars bearing toxic metals solutions was sometimes reported.

The presence of NOx in the atmosphere is an environmental challenge that needs to be addressed. Good NOx removal efficiencies have been attained by photocatalytic activity of TiO2 under UV light. TiO2 has been incorporated to cement-based materials to obtain depollutant and self-cleaning building materials. With the aim of broadening the sensitivity of these materials towards the visible light, two doped photocatalytic additives based on TiO2 were synthesized and used. Flame spray pyrolysis (FSP) allowed us to obtain TiO2 doped with either Fe or V, which generated hole-electron pairs with band gaps corresponding to visible light. Fe-TiO2, V-TiO2 and plain TiO2 were added (up to 2.5 wt.%) to different binding matrices: Portland cement (OPC) and air lime. The effect of the three photocatalytic additives on the setting time, consistency and mechanical properties of the cements were assessed.

The behaviour of different superplasticizers admixtures was assessed for hydrated lime pastes and mortars. Sometimes, air lime pastes and mortars were modified with two supplementary cementing materials (SCMs), namely nanosilica (NS) and metakaolin (MK). Two different polycarboxylate ethers, a lignosulfonate and a naphthalene condensed sulfonate superplasticizer were added to lime pastes and mortars and their effects on fresh-state properties as well as on the mechanical strengths were evaluated. A close relationship was found between the molecular architecture of the plasticizers and the flowability of the pastes. Zeta potential assessment allowed us to elucidate the main action mechanisms for these admixtures. In the case of polycarboxylate ethers, the large specific surface area of nanosilica led to a large SPs consumption as compared with metakaolin with lower surface area. However, polycarboxylate ethers in MK-lime samples were attached favourably to the C-S-H and aluminate hydrates, so that the dispersing action was greater with respect to NS-lime suspensions.

In order to evaluate the photocatalytic activity of several mortars modified upon the addition of photocatalysts, a laminar flow system was designed with the aim of assessing the abatement of pollutant NOx. The system consists of a photoreactor, where the samples to be studied must be placed, an irradiation source and a chemiluminiscence detector, all of them connected by a manifold. The NO source is a commercial mixture of NO and inert N2, and the flow can be adjusted to provide different NO concentrations (usually around 1000 ppb). Three gas mass controllers set the flows of NO, dry-air and wet-air. Therefore, the system allows to adjust the relative humidity by mixing in different ratios the wet and dry air, controlling it by a humidity sensor. The total flow ranges from 0 to 3 L·min-1. Then, the total flow is directed into the photoreactor. The upper part of the photoreactor is made of a quartz cover allowing either the visible or the UV irradiation reach the sample. When the irradiation source is switched on, NO is partly oxidized due to the photocatalytic reaction that takes place on the surface of the additives. The outflow goes from the photoreactor to the chemiluminescence detector that continuously records the NO concentration. Finally the chemiluminescence detector is able to quantify NO and/or NOx concentrations, and from those values NO2 concentration can also be estimated

4 p., tablas -- Comunicación presentada al VIII Congreso Español de Biogeografía celebrado del 23 al 26 de septiembre de 2014 en Sevilla., [EN]A first approach to the phytodiversity of Juniperus woodland at Doñana National Park has been drawn up. The methodology used is based on the Braun Blanquet method. The results are reflected in a phytosociological table in which are captured the obtained data referred to the floristic richness of the three existing fragments: Sabinar del Ojillo, Sabinar del Marqués and Sabinar del Charco del Toro. The total number of identified taxa is 97, from which 73.1% of them are herbaceous plants, and the rest woody plants. There is a low richness variability among these fragments. The biodiversity found is similar to that of the Mediterranean littoral Juniperus turbinata woodlands of continental islands, but lower than the juniper woodlands of the oceanic islands., [ES]Se realiza una primera aproximación a la fitodiversidad de los sabinares del Parque Nacional de Doñana. La metodología utilizada se fundamenta en la de Braun Blanquet. Los resultados se reflejan en una tabla fitosociológica. En ella se plasman los datos obtenidos referidos a riqueza florística de los tres fragmentos existentes: el Sabinar del Ojillo, el Sabinar del Marqués y el del Charco del Toro. El número total de taxones identificados es de 97, de los que un 73,1% son plantas herbáceas y el resto leñosas. La variabilidad de la riqueza es muy escasa entre los fragmentos. La biodiversidad encontrada es similar a la de los sabinares Mediterráneos costeros de Juniperus turbinata de islas continentales, pero inferior al detectado en los sabinares del mismo taxon en islas oceánicas., Este trabajo se ha realizado gracias al proyecto CSO2011-24425 de la Secretaría de Estado de Investigación, Desarrollo e Innovación (Ministerio de Economía y Competitividad).

Audiovisual media are nowadays appropriate tools to help illustrate the development of lectures by university professors. The 21st century students use them at ease, finding them an excellent companion to study certain subject topics. In particular, in the field of experimental sciences –as Chemistry- the advantages of using these materials are clear, both in portraying in a more visible way some abstract concepts and related phenomena and in the student's own approach to more practical aspects related to professional skills and practice upon completion of studies. This paper evaluates the results of applying the new technologies in the teaching of chemistry to undergraduate students of the University of Navarra. It also aims to target examples of the professional day to day activity of a Chemist and provide sound theoretical background as well as practical approaches to problem-solving tasks in any areas of Chemistry. Students’ perception has certainly been positive in terms of an increase of interest for the topics involved and well as an improved understanding of them.

This work deals with the effect of the nanosilica addition on the performance of aerial lime mortars. Several lime mortars were prepared and modified upon the addition of 3, 6, 10 and 20 wt.% of nanosilica. The presence of nanosilica increased the water demand of the fresh mixtures and reduced the appearance of superficial cracks after the spreading of the mortars onto a porous stone. Setting time underwent a delay when the amount of nanosilica ranged from 3 to 10 wt.%. However, samples with 20 wt.% of nanosilica showed a shortened setting time compared to plain lime mortars. Nanosilica reacted with Ca(OH)2 particles, yielding C-S-H compounds and, acting as a nanofiller, nanosilica also caused a pore blockage in the mesoporous range. These facts resulted in an increase in both compressive strength and durability after undergoing freezing-thawing processes. Overall, the addition of nanosilica clearly improves several characteristics of the aerial lime mortars in order to prepare enhanced mixtures to be used for restoration works.

Los medios audiovisuales son herramientas adecuadas hoy en día para ilustrar el desarrollo de las clases magistrales impartidas por el profesor universitario. El alumno se desenvuelve con soltura en estos soportes, y la utilización de estos medios es un óptimo complemento para una buena comprensión del tema. Particularizando esta acción en estudios experimentales, como la Química, las ventajas que aporta el empleo de estos materiales son claras, tanto en el entendimiento de los temas como en el propio acercamiento del alumno a aspectos más prácticos y relacionados con el ejercicio profesional al que se dedicarán cuando finalicen los estudios. El presente trabajo evalúa los resultados de aplicar las nuevas tecnologías en la enseñanza de la Química a estudiantes de la Universidad de Navarra. Se pretende identificar elementos propios del ejercicio profesional del químico y relacionar los contenidos teórico-prácticos de las asignaturas con el mismo, consiguiendo además con ello un mejor conocimiento de la materia objeto de estudio. La percepción de los alumnos ha sido ciertamente positiva en términos de un incremento de interés por las materias implicadas y de una mejora en la comprensión de las mismas.

En la presente tesis doctoral se han preparado y caracterizado, desde un punto de vista estructural, microestructural y eléctrico, láminas delgadas ferroeléctricas de titanato de plomo (PbTiO3, PT) a tan sólo 400°C mediante PCSD, diseñando para ello una nueva estrategia de síntesis de las disoluciones precursoras. La fabricación de las láminas se ha llevado a cabo mediante el depósito de las disoluciones por spin-coating sobre substratos de Pt/TiO2/SiO2/(100)Si seguido de un secado y un tratamiento térmico en un horno RTP combinado con irradiación UV para favorecer la eliminación de los orgánicos y la cristalización del óxido a baja temperatura. El titanato de plomo cristaliza con estructura perovsquita y es el ferroeléctrico por excelencia, presentando un alto valor de polarización espontánea Ps~50μC/cm2. Por este motivo, este óxido ha sido elegido como objeto de este estudio. El responsable de una reducción tan significativa en la temperatura de procesado de las películas de PT es un compuesto fotosensible, N-metildietanolamina (MDEA), utilizado por primera vez en la fabricación de láminas con este fin, que no presenta toxicidad y con un máximo de absorción muy próximo a la longitud de onda de la lámpara utilizada en la irradiación (222 nm). La caracterización de los soles pone de manifiesto que el MDEA forma complejos con los cationes metálicos presentes en el sistema, que son los responsables de una alta absorción en el UV a través de un proceso de transferencia de carga, un tipo de transición electrónica con coeficientes de absortividad molar muy superiores a los que presentan las transiciones π-π*, que son las que experimentan habitualmente las disoluciones precursoras fotoactivadas en la técnica PCSD. La reducción en la temperatura de cristalización del óxido se debe tanto al aumento de la fotosensibilidad de las disoluciones precursoras debido a la existencia de transferencias de carga en los complejos que forma el compuesto MDEA, como a un fenómeno de autoignición que tiene lugar en el sistema debido a la presencia del nitrógeno del MDEA junto a un alto contenido de orgánicos, que origina una gran cantidad de energía que el sistema consume en la cristalización del óxido, reduciéndose así la temperatura. De esta forma, MDEA proporciona unos resultados que otros fotoactivadores no permiten obtener. De este modo, se esperarían los mismos efectos para cualquier composición que contuviera al menos un catión de configuración d0 o d10, puesto que son los complejos que forma el MDEA con los cationes metálicos de este tipo los responsables del aumento de la fotosensibilidad de las disoluciones precursoras a través de las transferencias de carga. Como las principales familias de ferroeléctricos contienen cationes de este tipo, esta nueva estrategia de síntesis abre las puertas a la preparación de una gran variedad de composiciones de óxidos mixtos funcionales con gran interés aplicativo en dispositivos electrónicos.

Tradicionalmente se han descrito factores asociados a la Lactancia que varían en las diferentes culturas. En Colombia, los indicadores de prevalencia de la Lactancia materna exclusiva y duración de la Lactancia están lejos de las recomendaciones establecidas por la Organización Mundial de la Salud (OMS). El Departamento de Pediatría del Hospital Universitario Clínica San Rafael, teniendo en cuenta los beneficios que la leche materna tiene, ha venido trabajando en los últimos años en pro de rescatar la lactancia como una práctica cultural adecuada. En respuesta a esta necesidad creó en Agosto de 2004 el programa institucional de Lactancia "Primero los niños, niñas y adolescentes", a partir del cual surgieron varios interrogantes acerca del comportamiento de la lactancia en nuestro medio, que dieron origen al presente trabajo de investigación. Se diseñó un estudio de cohorte prospectivo realizado mediante la aplicación de una encuesta a 372 madres de recién nacidos sanos en postparto. La cohorte se reclutó entre julio de 2007 y junio de 2008 y se siguió hasta los 24 meses de edad del bebé con el fin de determinar la duración de la lactancia, sus factores condicionantes y las causas más frecuentes de su abandono. Se estableció la salida de los pacientes del estudio al cumplir 24 meses (recomendación de la OMS de la duración de lactancia) o al documentar su abandono antes de los 24 meses. Se encontró una lactancia materna exclusiva a los 6 meses de 14.7% y una duración acumulada de 14 meses para la población analizada. Traditionally, factors associated with breastfeeding which vary according to the different cultures have been described. In Colombia, the indicators of exclusive breastfeeding prevalence and breastfeeding duration are very far from the recommendations settled by the World Health Organization (WHO). The Pediatrics Department of the Hospital Universitario Clínica San Rafael, taking into account the benefits provided by the breast milk, have been working for the last years in favor of rescuing the breastfeeding as a suitable cultural practice. In response to this need, in August 2004, it created the Breastfeeding institutional program "First boys, girls and adolescents", form which various questions emerged regarding the breastfeeding behavior in our environment, which gave rise to the present research work. A cohort, prospective study was designed, conducted by administering a survey to 372 mothers of healthy newborns in post partum. The cohort was recruited between July 2007 and June 2008 and was followed-up until the infants were 24 months of age with the aim of determining the breastfeeding duration, its conditioning factors and the most frequent causes for its drop-out. The infants were to be withdrawed from the study when they completed 24 months of age (Breastfeeding duration recommended by the WHO) or upon documenting their drop-out before 24 months of age. 14.7% of exclusive breastfeeding at 6 months and a cumulative duration of 14 months were found for the examined population. Tradicionalmente foram descrito fatores associados à amamentação que variam nas diferentes culturas. Na Colômbia, os indicadores de prevalência da amamentação materna exclusiva e duração da amamentação estão longe das recomendações estabelecidas pela Organização Mundial da Saúde (OMS). O Departamento de Pediatria do Hospital Universitário Clínica San Rafael, tendo em conta os benefícios que o leite materno tem, vem trabalhando nos últimos anos em prol de resgatar a amamentação como uma prática cultural adequada. Em resposta a esta necessidade criou-se em agosto de 2004 o programa institucional de Amamentação "Primeiro as crianças e adolescentes", a partir do qual surgiram várias dúvidas sobre o comportamento da amamentação em nosso meio que deram origem a este trabalho de pesquisa. Foi desenhado um estudo de cooorte prospectivo realizado mediante a aplicação de um questionário a 372 mães de recém nascido sãos em pós-parto. A população foi recrutada entre julho de 2007 e junho de 2008 e foi seguida até os 24 meses de idade do bebê com o objetivo de determinar a duração da amamentação, seus fatores condicionantes e as causas mais frequentes de seu abandono. Foi estabelecida a saída dos pacientes do estudo ao completar 24 meses (recomendação da OMS da duração da lactação) ou ao documentar seu abandono antes dos 24 meses. Encontrou-se uma lactação materna exclusiva aos 6 meses de 14.7% e uma duração acumulada de 14 meses para a população analisada.

The aims of this study were the preparation and the characterization of optical materials based on three dimensional ordered arrays of colloidal latex particles, which are also called colloidal crystals (CCs). Although these multilayered latex particles arrays do not exhibit a photonic bandgap (PBG), the fabrication and the research of the optical properties of CCs based on polymeric colloidal particles are not only useful as templates to synthesize PCs but also because, due to their composition and their structure, they could present very interesting applications, such as those derived of the interaction with light (difraction, interference, scattering, absorption, inhibition, ...), maximal packing density, maximal structural stability, maximal catalytic and reactivity inside them and the ability to create media for information storage (pre{formatted substrates), among others. Lots of different techniques and sources of knowledge contribute to develop and explain the photonic phenomena. Physicists, chemists and engineers work together in the photonic field. This interdisciplinary nature of the problem enriches it. The main ideas of polymerization and colloidal crystallization are commented in the Introduction. In chapter 1, not only modified emulsion and dispersion poly- merization techniques based in styrene and acrylate monomers, but also the surface functionalization and the purification and characterization of the colloidal latex particles synthesized are explained in detail. In chapter 2, the fabrication of 3D ordered arrays of colloidal particles by vertical deposition and sedimentation methods, and the investigation of the optical properties and crystalline structure of the colloidal crystals by spectroscopy, optical microscopy and optical diffraction techniques are explained. Finally, the conclusions of the study are reported in the last chapter.

We probe the local and global structure of spin-coated colloidal crystals via laser diffraction measurements and scanning electron and atomic force microscopies, and find that they are unique three-dimensional orientationally correlated polycrystals, exhibiting short-range positional order but long-range radial orientational correlations, reminiscent of—but distinct from—two-dimensional colloidal hexatic phases. Thickness and symmetries are controllable by solvent choice and spin speed. While the polycrystallinity of these colloidal films limits their applicability to photonics, we demonstrate their feasibility as templates to make crack-free magnetic patterns.