- Development of new liquid crystals working at infrared and microwave range.
- Nanostructured materials based on the combination of nanoparticles (nanotubes, nanorods, nanowires) with self-organized systems (e.g. ferroelectric liquid crystals).
- Aptamers as active specific sensing nucleic-acid chains for the construction of portable biosensors.
- Multiferroic ceramic nanoheterostructures.
On the basis of these four pillars, several devices are proposed in this preliminary stage as an open list of possible objectives for the development of ICT technologies. As the project progresses new proposals will be included in the work schedule.
This Action will build on long experience in materials engineering of liquid crystals (LCs), particularly state-of-the-art realizations such as orthoconic antiferroelectric smectics, high birefringence or negative anisotropy nematics as well as their composites with functional polymeric networks. These materials show superior performance in dynamic response, bistability, phase-only switching, etc. These properties are further boosted by doping with nanoparticles of specific size, shape (nanorods, nanotubes), composition and electrical behavior.
Adaptive and tunable electro-optical components: the combination of novel liquid crystal modes such as polymer stabilized blue phases with microstructured polymer surfaces and/or with nanosized particles is a promising route towards the creation of a whole new range of electro- optical components. While the basic operating principles are long known, it is only recently that new liquid crystal modes with fast switching behavior (even for thick layers) have become feasible. Furthermore, progress in nanoparticle technology and microstructuring or polymer with optical qualities has brought these technologies to unseen levels that are ready to be combined with the innovative LC technologies. The main objective now is to start exploring the vast area of new opportunities that this has created. Starting from basic test structures to assess the predicted operation, this COST Action will gradually move to more complex components that exhibit presently non-existing functionalities.
The search for coupling of properties in multiferroic ceramics is relevant for the development of new and unusual applications. So far multiferroics are afforded in single phase and composites but only nanoheterostructures found relevant properties. Ceramic grain size generally does not fit the crystallite size due to the presence of crystalline defects. It is necessary to understand the role of crystalline defects and size effects in their functional properties.
The study will focus on selected materials in which the groups show expertise and international recognition: semiconductor nanoparticles, giant dielectric constant ceramics, lead free piezoelectrics and magnetoelectrics. The cooperation will allow this COST Action to compare different processing routes to obtain from nanoparticles to dense nanostructure ceramics with different crystal defects, size effects and dimensionality.
On the other hand, biosensors for health point-of-care (PoC) instrumentation are other challenging objective for the new European society. Significant progress in the ability to predict, diagnose and monitor cheaply and effectively in real time and/or at PoC is needed. New biosensors such as aptamers combined to innovative detection systems such as functionalized LCs or high frequency resonators with carbon nanotubes working in liquid medium are promising alternatives to develop low cost diagnostic tools for primary assistance. LC and micro/nanoluminophores may be used as converters of X-ray into visual effect with low radiation exposition.
Bulk acoustic wave resonators (BAW) are heavily used in biosensing applications, as they possess the combined merits of all other types of biosensors: label-free, small size, arrays for parallel detection, ultra-high sensitivity and low cost. However selectivity to different biological species must be enhanced. Some groups have proposed, realized and published a novel technology for replacing metal electrodes on BAW devices with carbon nanotubes (CNT), demonstrating significantly better sensitivity with these novel electrodes.
Chemically functionalizing CNTs or piezoelectric nanowires for direct bonding to specific biological molecules would prevent non-specific binding and the need of additional sensitizing layers. The success of this Action will bring an early development of this highly sensitive and innovative technology allowing the applicants to gain a technological lead in the world.
Scientific work plan methods and means
This COST Action will establish several working groups to interchange knowledge and people.
LC modification with nanostructures
Combining gold nanoparticles (NPs) and CNTs with LC phases produces new systems keeping the properties of LCs and the localized surface plasmon response of very well dispersed NPs. Additionally, it has recently become feasible to realize a Blue LC Phase that is stable in a wide temperature range. The interaction of polymer nanostructures with LC molecules is a vast and unexplored area of research with tremendous potential. Functionalization of the LC ordering and stabilization of screw dislocations −like in case of Blue phases, smectic phases and TGB phases−as well as the impact of functionalization of NPs of various shapes ranging from graphene and laponite disks and spherically shaped plasmonic, semiconducting and magnetic nanoparticles are essential as well.
Recently the first soft magneto-electric, as a new subgroup of multiferroic materials, was prepared, by mixing magnetic nanoparticles and LC phase. A study of the influence of the magnetic nanoparticles surface properties on the mechanism of coupling with different LC phases appears to be fundamental.
Biosensors and reading electronics
Novel biosensors based on BAW resonators, where a thin film of CNTs or graphene layer doubling as electrode and sensing layer, will be jointly developed. This technology would solve many of the issues of existing biosensors in terms of sensitivity and selectivity. To successfully realize this goal, the expertise of several applicants in BAW resonators design and fabrication, nanostructures growth and characterization, and electronics integration is essential.
Novel biosensors based on BAW resonators and LC cells having active surfaces coated with highly specific aptamers for detection of food-borne pathogens in simple, portable units will be prepared.
New ICT devices based on reconfigurable LCs and unconventional materials
A polymeric template can be used to introduce a preferential alignment to LCs doped with metal nanoparticles as well as photosensitive and photo-oriented additives. It has been recently demonstrated that the plasmon resonance spectral position of these NPs can be dynamically controlled. This kind of research can lead to the realization of active plasmonic devices. Similar structures comprising NPs of crystalline materials with strong nonlinear optical properties are expected to be promising for realization of active multispectral optical devices.
Furthermore, the combination of micro- and nanostructured optical surfaces with Blue Phase LCs allows the realization of smart optical components with switchable or tunable optical functionality.
Tools for Integration; Tools for Dissemination
Continuous exploration of new funding resources will be performed by contacting new European research groups and companies that could collaborate with the COST Action. Visibility and dissemination of results will be of major importance for this task. Attendance at conferences worldwide and the organization of specific workshops will be the most powerful tools for the success of this WG.