MATERIALS FOR INDUSTRIAL AND MEDICAL APPLICATIONS

At Kelways, the research and development for sustainable, abundant, recyclable, toxic-free, and environmentally friendly materials is the core of Kelways business model. We have over 10 years of experience in several fields: pharmaceutical, coatings, adhesives and sealants, photoactivated materials, biomarkers, and many more.


The properties of metal nanoparticles are different from the bulk and new properties emerge at the nanoscale. During the last fifty years, there has been a continuous development in understanding and controlling the optical and catalytic properties of noble metals at the nanoscale.


A large number of different applications emerged during the previously mentioned development: catalysis, electrocatalysis, photocatalysis, sustainable energy, imaging, sensors, nanomedecine, and even artistic applications. Our understanding of optical properties of bulk and metallic nanoparticles (NPs)(monometallic NPs and nanoalloys) has enhanced exponentially due to the innovative variety of microscopic characterization techniques and light sources such as pulse modulated fast lasers ranging from femtosecond laser pulses into continuous monochromatic lasers .  

 
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LIGHT TO HEAT CONVERSION MATERIALS 

Kelways is capable of synthesising nano and micro heaters in different shapes and forms. 
The image above demonstrate the thermal effect of plasmonic quasi-spherical gold nanoparticles (NP) via computer simulations of the electromagnetic and thermal properties of a single NP heater. (a) Model of a single Au-NP in a thermally-conductive matrix. (b,c) Absorption cross sections and spatial temperature distributions for single Au-NPs. (d) Temperature at the surface of a single NP as a function of the NP diameter. Inset: Temperature map for a 10nmNP in water. 

Large nanoparticles in the trimer play the role of the nano-optical antenna whereas the small nanoparticle in the plasmonic hot spot acts as a nano-heater.

The principles of heat localization described here can be potentially used for thermal photo-catalysis, energy conversion and bio-related applications. 

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GEOMETRICALLY TUNABLE OPTICAL PROPERTIES

Gold nanorods (NRs) have recently attracted a lot of attention because of their exceptional optical properties and their potential applications in nanomedicine and the field of sensors. 
Indeed, they present two surface plasmon resonance (SPR) absorption bands corresponding to the electromagnetic wave-driven oscillation of the quasi-free electrons along (longitudinal SPR, LgSPR) and perpendicular (transverse SPR, TrSPR) to the rod long axis).

Whereas the TrSPR is almost insensitive to the NR morphology, the spectral location of the longitudinal one (LgSPR) can be easily tuned from green to near-infrared by modifying the NR aspect ratio: the longer the rod is,
the smaller the LgSPR frequency. On the basis of these properties, noble metal NRs are promising nanoparticle for hyperthermal therapy against cancer and optical data storage, as well as decorative applications, solar PV and much more. 

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MATERIALS FOR HETEROGENEOUS CATALYSIS 

Palladium nanostructures have attracted a lot of interest these last decades because of their applications in catalysis and electrocatalysis, in hydrogen storage, in the field of sensors as well as in nanomedicine. d is used in a large number of industrially important reactions such as hydrogenation of unsaturated organic compounds and a number of C-C coupling reactions. Moreover, Pd nanoparticles (NPs) are efficient catalysts for environmental pollution abatement and automotive emission control. 

The irradiation of the palladium nanosheets generate “hot” electrons, then the electron-rich palladium nanosheets undergo the oxidative addition of aryl halide, followed by transmetallation of in situ formed aryl borate (the boronic acid is transformed after the reaction with base into a borate anion which facilitates the transmetallation).

Plasmonic catalysis enables to achieve reactions using solar light with less energy and time consumption. Palladium nanosheets exhibit a broad plasmon absorption band in the visible-near infrared domain. The catalytic activity of Pd nanosheets for Suzuki--Miyaura reactions was remarkably enhanced under visible light irradiation.

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MATERIALS FOR WATER DEPOLLUTION 

Titanium dioxide (TiO2) as a photo-activated nanostructure presents a very interesting material for many applications: self-cleaning surfaces, automotive industries, coatings and much more. 

The conductive properties of TiO2 photo-activated nano-structures were demonstrated via a prototype of a cyclic water-treatment unit presented in the image above. Two water solutions are running in cycles via a simple rotary pump. The water stream is divided into two compartments: one that contains TiO2 and a reference. The water is contaminated by a colorant used widely in fashion industry. Both compartments have TiO2 mesh surrounding a UV lamp and safely built-in absorbing glass to protect the eye witness. 
Without light, nothing happens. Yet, when illuminated by UV light, the pink-red polluted water running through compartment with TiO2 starts clearing up within minutes of cycles. This experiment was developed to demonstrate at Palace of Discovery - Paris - France the advances of nanotech for water depollution.