Bio-Nanohybrid materials based on clays and phospholipids

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada. Fecha de lectura: 13-10-201

All-natural and highly flame-resistant freeze-cast foams based on phosphorylated cellulose nanofibrils

Pure cellulosic foams suffer from low thermal stability and high flammability, limiting their fields of application

Functional biohybrid materials based on halloysite, sepiolite and cellulose nanofibers for health applications

Multicomponent nanopaper from the assembly of nanotubular halloysite, microfibrous sepiolite and cellulose nanofibers was developed for diverse functional applications such as slow release of antibacterial model drugs loaded into halloysite lumen

The use of ATR-FTIR spectroscopy for quantification of adsorbed compounds

Quantification of adsorbed amounts requires in most cases several assumptions. Adsorption of organic compounds, for example, is usually measured indirectly, by mass balance calculations based on the evaluation of the remaining chemical in solution. Such procedure might yield overestimates when precipitation or degradation of the adsorbate occurs and underestimates when separation of the sorbent material (e.g., clay particles) with the adsorbed chemical is not effective. This study presents a simple quantification procedure based on the ratio between IR absorption bands of the sorbate and the adsorbate. The advantages of the procedure are (a) direct evaluation of the adsorbed amount and (b) accurate measurement of chemicals that are hard to quantify, as those that do not absorb light in the UV-Visible range, or require expensive chromatography procedures.Bernd Wicklein thanks Comunidad de Madrid for financial support through Personal Investigador de Apoyo contract and E. Ruiz-Hitzky (ICMM-CSIC) for supporting this work through a CICYT project (Spain; MAT2009-09960)

The Use of ATR-FTIR Spectroscopy for Quantification of Adsorbed Compounds

Quantification of adsorbed amounts requires in most cases several assumptions. Adsorption of organic compounds, for example, is usually measured indirectly, by mass balance calculations based on the evaluation of the remaining chemical in solution. Such procedure might yield overestimates when precipitation or degradation of the adsorbate occurs and underestimates when separation of the sorbent material (e.g., clay particles) with the adsorbed chemical is not effective. This study presents a simple quantification procedure based on the ratio between IR absorption bands of the sorbate and the adsorbate. The advantages of the procedure are (a) direct evaluation of the adsorbed amount and (b) accurate measurement of chemicals that are hard to quantify, as those that do not absorb light in the UV-Visible range, or require expensive chromatography procedures

Freeze-casting of highly porous cellulose-nanofiber-reinforced γ-Al2O3 monoliths

Freeze-casting is a powerful consolidation technique for the fabrication of highly porous and layered-hybrid materials, including ceramic-metal composites, and porous scaffolds for catalysis, bone substitutes and high- performance membranes. The aqueous suspensions to be freeze-casted usually contain dense particles facilitating macroporous, layered ceramics with dense (nonporous) struts. In the present study, hierarchical macro-mesoporous alumina (HMMA) monoliths were successfully prepared by freeze-casting of aqueous suspensions containing hierarchically-assembled, mesoporous γ‒Al2O3 (MA) powder and cellulose nanofibers (CNF). As- prepared monoliths were ultra-porous (93.1–99.2%), had low densities (0.01–0.25 g/cm3), and displayed relatively high surface areas (91–134 m2/g), but were still remarkably rigid with high compressive strengths (up to 52 kPa). Owing to the columnar porosity and mesoporous nature of the struts the freeze-casted HMMA monoliths exhibited high permeability and high thermal insulation, the latter ranging from 0.039 W/m∙K to 0.071 W/m∙K, depending on pore orientation

Electro-conductive reinforced engineering ceramics and preparation thereof

This invention relates to a method of preparing a ceramic article which comprises mixing a ceramic powder and a nano-filler in water to form an aqueous suspension; drying said aqueous suspension to obtain a composite powder; forming said composite powder into a green body; and sintering said green body to form said ceramic article, wherein said nano-filler is an insoluble cellulose material. It also relates to methods of making composite powders and green bodies, as well as certain ceramic articles, powders and bodies themselves.Peer reviewedJozef Stefan Institute, Consejo Superior de Investigaciones Científicas (Español)A1 Solicitud de patente con informe sobre el estado de la técnic

Nanocarbon composite materials from natural precursors

Oral presentation given at the Baltic Polymer Symposium, held in Tallinn (Estonia) on September 20-22th, 2017.Nano-sized and nanostructured carbon allotropes are ubiquitous in advanced applications ranging from catalysis to batteries, supercapacitors, biomedicine, etc. Paradigmatic nanocarbons for these applications are carbon nanotubes, graphene and fullerenes including their modifications. However, these nanocarbons are generally produced from petro-derived precursors or natural graphite. Therefore, ‘green’ alternatives are sought not only for their production but also for the hybridization with other functional components. The Nanostructured Hybrid, Biohybrid and Porous Materials Group (http://www.icmm.csic.es/phbhmg/) has developed various synthetic routes for the environmentally benign production of these materials by microwave-assisted and sonochemical synthesis as well as low temperature carboreduction of natural carbon precursors like gelatin, bacterial cellulose or sucrose. These routes include the presence of inorganic nanoparticles like clays, silica or transition metal hydroxides that have a crucial role in the synthesis of the graphene-like materials. Our investigations have shown that these inorganic components promote the graphitization of the biopolymers, while getting integrated as functional component in the as synthesized carbon material. Clay supported graphene materials, carbon-silica foams or metal-carbon aerogels are only some examples of the nanocomposite and hybrid materials produced in this way. These materials were successfully applied in various applications like hydrogen storage, as electrodes in Li ion batteries and supercapacitors, as piezo elements in mechanical pressure sensors, or for electrochemically regenerated adsorbents of aromatic pollutants. Currently, investigation is focused on the incorporation of graphene nanoplatelets into functional hybrid materials assisted by an unique dispersion effect of the microfibrous clay sepiolite

Hierarchically structured bioactive foams based on polyvinyl alcohol-sepiolite nanocomposites

Hierarchically structured polymer-clay foams comprised of sepiolite and polyvinyl alcohol (PVA) are functionalized with enzymatic and conductive properties to be employed as bioreactors and 3D bioelectrodes. The concept of nanoarchitectonics was followed in the design of this hierarchical and multifunctional cellular material through tailoring of the properties at different length scales, interfacial properties of the sepiolite fibres through adsorption of lipid molecules, bioactivity by supramolecular assembly of urease enzymes on the sepiolite-lipid bio-nanohybrid, and meso- and macroporosity controlled by incorporation of the clay fibres into a PVA matrix, and further cross-linking with borax and ice-templating. The resultant bionanocomposite foams show high structural integrity, tailored multi-level porosity, and biocompatibility which is manifested in sustained enzymatic activity. Exploratory studies show that additional doping with carbon black rendered conductive foams that could hence find usage in bioelectrocatalysis. This journal is © 2013 The Royal Society of Chemistry.This work was supported by the CICYT (projects MAT2009-09960 and MAT2012-31759), the CSIC (project 201060I009) and the UE COST Programme (project MP1202).Peer Reviewe