1. Could you explain the significance of your article to the non-specialist? 

Chemists may now design nano-structured one-dimensional inorganic and/or hybrid materials (nanofibers, nanowires, nanotubes, nanohelices, etc.) by chemical methods (bottom-up approaches) that combine sol-gel and self-assembly procedures. These synthetic procedures try to mimic what Nature does (bio-inspired routes) to elaborate complex biomineral structures, hierarchically-organized at different length scales. Herein we show an interesting way to replicate oxide-based inorganic materials (i.e. silica) with size-controlled nanofibrous morphologies, using in situ- or pre-assembled fibrous gels as organic templates. The extension of this work to iron oxide opens a land of opportunities to design nanofibers and/or nanotubes of any inorganic phase (i.e. transition metal mixed oxides), with tuneable properties suitable for interesting advanced applications (catalysis, sensors, magnetic media, nanoelectronics, etc.).

 

2. What has motivated you to conduct this work? 

From my post-doctoral work in Clement Sanchez's laboratory I become fascinated by the possibility that chemists have now at hand to prepare inorganic and/or hybrid (organic-inorganic) materials with a tailored texture (porosity), shape and/or morphology hierarchically-organized at different length-scales (from several amstrongs to microns), through the use of different self-assembly or co-assembly procedures. I consider very challenging and motivating the possible patterning of inorganic nanostructures with controlled fibrous morphologies (traditionally prepared as bulk powders) with the aid of previously or in situ formed superstructures of organic assemblies. The development of this field can provide easily accessible chemical methods for the tailor-design of nanostructured multifunctional materials with improved and/or new advanced properties to be exploited by the nanotechnology sector.

 

3. Where do you see this work developing in the future? 

Important achievements have been already attained in this field, mainly with silica and other purely inorganic single oxides (titania, alumina, etc.), which have been prepared as mesoporous powders and/or films and also as fibrous nano-objects with different and controlled morphologies (helices, wires, tubes, ribbons.). Our research efforts in the future will be directed to extend this approach to more complex inorganic systems (for instance, transition metal mixed oxides), and also to hybrid organic-inorganic materials functionalized in different ways. In this respect, investigations should clarify whether the crystallization processes of multi-metallic systems into structures presenting interesting electrical, optical and/or magnetic properties (such as ferrite spinels, perovskites, ilmenites, etc.), may also be constrained to or shaped as one-dimensional nanostructures (nanofibers and/or nanotubes with nanocrystalline walls) using the gelator-template approach. In this case, improved or even unexpected properties and applications could be derived. 

 

4. Are there any particular challenges facing future research in this area? 

Undoubtedly, the design of highly anisotropic one-dimensional nanostructures (nanofibers, nanotubes, nanohelices, and so on) by combing sol-gel (or chimie douce) and self-assembly procedures will continue to be a focus of intense research in the future. Compared to conventional bulk materials, these low-dimensional nano-scale materials (with their large surface areas and possible quantum-confinement effects) may exhibit improved and/or distinct electronic, optical, chemical and thermal properties, becoming potential candidates for many advanced applications (optoelectronic or nanoelectronic applications, such as photonics, sensors, nanocapacitors, etc.) With this purpose in mind, chemists, biologists, physicists, and material engineers will all have to work together in an inter-disciplinary way. In this sense, scientists must keep on learning from the "school of nature", where organic (bio)molecules and mineral (inorganic) species are combined in a synergic or cooperative way (in time-dependant processes) to elaborate complex biomineral structures, hierarchically-organized at different length scales. Some examples can be found in the siliceous structures of radiolarian and diatoms, or in the composite systems forming the crustacean carapaces and bone or teeth tissues in vertebrates.