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)

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

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

Biomimetic interfaces for detection of and protection from Influenza

Poster presented at the Fourth International Conference on Multifunctional, Hybrid and Nanomaterials, held in Barcelona (Spain) on March 9-13 March, 2015

Tuning the Nanocellulose-Borate Interaction to Achieve Highly Flame Retardant Hybrid Materials

Tuning the Nanocellulose–Borate Interaction To Achieve Highly Flame Retardant Hybrid Material

Cellulose nanofibers as substrate for flexible and biodegradable moisture sensors

Flexible and biodegradable electronics is attracting the interest of the Internet of Things industry. The necessity of sustainable development and environmental friendly electronic devices forces manufactures to reduce electronic wastes and toxic residues. Cellulose nanofibers are biodegradable and flexible materials suitable to build self supported film electronics and are seeing first employment in sensor fabrication. In this work, cellulose nanofibers based moisture sensors are reported, which are characterized at different working frequencies showing a good dependence with relative humidity (RH). A transparent and fully biodegradable moisture sensor was fabricated based on a PEDOT:PSS electrode showing a wide operation range from 20% to 85%RH, where CNF film acts as the sensing layer without any additional processing. In order to manufacture the sensor, a one-step fabrication method based on screen-printing was applied, which offers a more reproducible and cost-effective solution than others techniques. In addition, this method offers the possibility to easily redesign the sensor saving time and money. Thus, our work presents a versatile, transparent, self-supported film moisture sensor with a promising adaptability to the green-electronics industry.H2020-MSCA-IF-2017-794885-SELFSENSMAT2015-71117-RID2019-107022RJ-I00IJCI-2015-2388