During the initial 36 months of the project, Tekniker and Millidyne have synthesized a wide range of mesoporous silica nanoparticles being spherical shape, average size=120 nm and with a high specific surface area=700-1000 m2/g to allow the incorporation of the essential oils. Different versions of the nanoparticles (with copper), with essential oils, or a combination of some of them have been prepared at semi-industrial scale by Millidyne. Moreover, smart-release systems were developed by grafting stimuli-responsive polymer brushes (PDMAEMA (Poly(2-(dimethyl amino)ethyl methacrylate)), PDEAME (Poly(2-(diethylamino)ethyl methacrylate)), and PNIPAM (Poly(N-isopropylacrylamide))) onto Cu-SMIN via surface-initiated atom transfer radical polymerization. The successful functionalization has been confirmed by different physicochemical analysis and the incorporation of EOs has been done through a proved scalable and reproducible method. Smart behaviour of functionalized particles was demonstrated at lab scale via pH and/or temperature-triggered size changes, and the release of carvacrol, an antimicrobial essential oils, seems to be confirmed using electrochemical sensors developed by the University of Rome Tor Vergata. Figure 1 showed an image obtained by transmission electronic microscopy (TEM) of SMIN particles and SMIN particles functionalized with stimuli-responsive polymer brushes.
Moreover, a broad range of AMP samples were produced by the HESSO via alkaline hydrolysis, yielding with strong antiviral activity confirmed—up to 88.5% inhibition by the >10 kDa fraction at 50 mg/mL.
Moreover, RELIANCE has developed greener binders to be used for coatings. Firstly, fluorine- and silver-free bio-based PU formulations were developed by Centexbel for antimicrobial textile coatings and digital printing. These coatings exhibited excellent industrial wash fastness and hydrostatic pressure resistance. Various bio-based polyols were assessed: Sebacate-based PU demonstrated high tensile strength and durability (>20 wash cycles), Succinate-based PU showed outstanding elongation, and PCL-based PU reached 80% biodegradability. Chemical recycling of PU-coated fabrics using a ZnCl2 catalyst enabled complete removal of the coating without degrading the PET fabric. Using a bioinspired approach with controlled physical shrinkage and a dual-layer design, a nanostructure pitch is generated, but optimization is underway to improve repellency and durability. These results confirm the potential of sustainable PU systems for advanced textile applications, as should be confirmed by Alsico High Tech in the following months.
Regarding the development of inorganic (hybrid) sol-gel based and fluorine free coatings for Home Appliance applications, Polyrise has prepared coatings that exhibiting good adhesion, good and smooth appearance, Hardness in the range from 2 to 6 N according to ISO 4586-2 (depending on substrates) when samples are cured @160°C could be achieved, as well as WAC as high as 107° and HAC of 38° (surface energy around 22 mN/m). So far, coatings 45-65 wt% water containing formulation was applied by dip or spray and the coatings are being nanostructured through the dispersion of RELIANCE’s nanoparticles. The coatings are being characterized by ARCELIK to analysis their suitability for being used in interior and exterior parts of a fridge.
Finally, the cold atmospheric plasma enabled the successful deposition of antimicrobial peptides and nanoparticles onto surfaces from the automotive sector, which are being validated by Maier. Nisin and keratin peptides were deposited using nitrogen and argon plasma, and also SiO2 and Cu-SMIN particles have been shown that can be deposited by this technology, being co-injected with antimicrobial peptides. Even if the antimicrobial activity of developed coatings should be improved, the results obtained by the School of Engineering and Architecture, in collaboration with MPG, encourage further investigation in this line as the amount of material and chemicals required by the technology is very low.
At RELIANCE, not only the antibacterial and antiviral properties of new generation antimicrobial formulations and nanocoatings are being evaluated by the University of Rome Tor Vergata in collaboration with Defence Institute for BioMedical Research group; but also their potential hazards by INERIS.
To validate the environmental benefits of implementing these nanocoatings, Tekniker is working on the sustainability of the process and end-life of the products, while School of Engineering and Architecture is working on the techno-economic evaluation. More information about implementing the dissemination & communication activities can be obtained from EUROPROJECT.
