Functional Hybrid Nanopaper by Assembling Nanofibers of Cellulose and Sepiolite

Abstract

Functional heterofibrous hybrid materials are prepared in an integrative approach from aqueous dispersions of nanofibrillated cellulose and sepiolite by applying high shear homogenization and ultrasound irradiation. Both types of nanofibers remain physically cross-linked forming homogeneous and very stable high-viscosity gels that can be shaped as films and considered as "hybrid nanopapers" as well. The presence of sepiolite modifies the surface roughness of the films resulting from the casting process, which can be rendered hydrophobic, as the hydrophilic characteristics of both components resulted modulated. In addition, these fibrous hybrid systems can benefit from the properties provided by the two components, such as mechanical behavior, surface properties, and chemical reactivity. Moreover, further assembly of these hybrid nanopapers to other particulate solids, such as carbon nanotubes, magnetite, or ZnO nanoparticles, results in multifunctional hybrid nanopapers, opening a versatile way for developing other numerous organic-inorganic materials of interest in diverse applications.

Immobilization of Nanoparticles on Fibrous Clay Surfaces: Towards Promising Nanoplatforms for Advanced Functional Applications

“…Sepiolite has been also cross‐linked to cellulose nanofibers (CNF) using ultrasonication to produce very stable viscous gels from which it is possible to produce films that can be considered as “hybrid nanopapers” ,. Actually, combination of CNF to diverse type of inorganic nanoparticulated solids, such as Ag, Ni, Fe 3 O 4 , TiO 2 , carbon nanotubes or graphene, is an attractive topic of research addressed to the preparation of new systems for applications in catalysis, environmental remediation, sensors and biosensors, etc .…”

“…Sepiolite has proved to be also of crucial importance in the preparation of fire‐retardant foams based on bacterial cellulose and containing graphene oxide as well . In our case, the use of the ultrasonication treatment is essential for stabilizing hybrid hydrogels where both nanofibers (sepiolite and CNF) become de‐agglomerated and randomly dispersed which facilitates their further processing as films (Figure A) . Furthermore, the presence of sepiolite makes possible to additionally co‐assemble other type of nanoparticles, as for instance MWCNT (Figure B) or magnetite NP, which results in the incorporation of magnetic properties or electrical conductivity to the final materials, respectively ,.…”

“…In our case, the use of the ultrasonication treatment is essential for stabilizing hybrid hydrogels where both nanofibers (sepiolite and CNF) become de‐agglomerated and randomly dispersed which facilitates their further processing as films (Figure A) . Furthermore, the presence of sepiolite makes possible to additionally co‐assemble other type of nanoparticles, as for instance MWCNT (Figure B) or magnetite NP, which results in the incorporation of magnetic properties or electrical conductivity to the final materials, respectively ,. Alternatively, it is possible to use modified sepiolite, to which it has been previously assembled of other NP, instead of the neat clay.…”

“…Alternatively, it is possible to use modified sepiolite, to which it has been previously assembled of other NP, instead of the neat clay. Thus, for instance the use of ZnO‐sepiolite leads to materials of potential interest in photocatalysis . These are only the first examples of CNF‐sepiolite nanoarchitectures developed by this methodology, promising results that clearly open the way to the development of many other functional hybrid nanopapers of interest for applications in diverse fields.…”

The Meeting Point of Carbonaceous Materials and Clays: Toward a New Generation of Functional Composites

“…The elastic modulus of the generated composite materials (10 wt% sepiolite and 0.8 wt% MWCNT) induced an improvement from 0.7 to 2.2 GPa in Young's modulus (Figure ‐vi). Recently, the excellent dispersion of CNT in the presence of sepiolite has been exploited to facilitate their combination with gels of cellulose nanofibers under ultrasonic irradiation, giving rise to homogeneous gels of these three components that can be processed as uniform self‐standing nanopapers provided with electrical conductivity. In summary, promoting the dispersibility and aqueous stability of carbon nanotubes by clay particles in liquid media paved the way for more efficient reinforced composite materials.…”