Impregnating nanoparticles in classical polymer substrata is one of the interesting strategies which may confer multi-functional and multi-purposed polymer-based structure. The potential applications extend from bio-compatible scaffold for different types of tissue growth [1], antimicrobial or antifouling surface layer [2], or even photocatalytic framework for enhanced reactional sites [3]. Nanoparticles aglomeration remains however a major concern during the fabrication of these “enhanced polymer substrate”. Recent work in our research group have shown promising rapid plasma synthesized Ag and Au nanoparticles with tuneable geometry, with furthermore a safe-by-design process [4]. Intermediate steps involving hazardous nanoparticles powder blending or dilution may be forsaken to incorporate the nanoparticles in polymer substrata. In this work, we incorporated the plasma synthesized Ag nanoparticles within a PDMS based microfluidic circuit. The microfluidic circuit is destined to offer eventual benchwork for fast photo-catalytical or antimicrobial activities evaluation. Optical spectroscopy measurements have been performed where the non-reflected and non-transmitted incident light were analyzed to attest the surface plasmon or localized plasmon band excitation. Contrary to classical analysis where non-transmitted incident light in the plasmon band is assimilated to the general term “plasmon absorption”, we succeeded in distinguishing cases where localized plasmon or propagating surface plasmon mode were excited. Herein the plasmon wavelength (400 – 450nm), the same level of non-transmitted light could be assorted with distinct levels of non-reflected light, giving key information on the migration and aggregates formation of AgNP within the PDMS substrate. The results also confirmed that the AgNP incorporation is subjected to aggregates formation with time.

The conformational studies in solution and in the solid state of substituted 6-methyl-4-hydroxy-2-pyrones indicated that the substituents on the 4-hydroxy group clearly favored the s-cis arrangement towards the formal double bond. Steady state kinetic NOE measurements of the tert-butyl, trimethylsilyl and the trimethylstannyl derivatives showed a marked preference for this conformation in solution. The structures determined by X-ray diffraction demonstrated the exclusive presence of the same conformation in the solid state. In these three derivatives, the pertinent dihedral angle deviates only slightly from the value for coplanarity with the formal double bond. The predictions of the τ-bond model are in accordance with the observations. The X-ray structure of the trimethylstannyl derivative reveals pentacoordinated tin with short contacts to the oxygens at the 2 and 4 position of neighboring molecules. The tin center plays both the role of a protecting group for the 4-hydroxy moiety and of a Lewis acid towards the 2-carbonyl oxygen. The X-ray structure of the stannyl derivative shows unique features which can be compared to the extended transition state of aldol reactions.

For many applications in cutting tools or watchmaking industries, the need to develop new solutions in order to improve the lifetime and performances of the components requires new approaches and solutions. In a joint project between the (Berner Fachhochschule) BFH and the (Haute Ecole ARC) HE-ARC, promising results have been obtained with nanotextured graphite layers produced using a two step hybrid production technology. First, a graphite coating is deposited using magnetron sputtering technology. Second, the coating is treated at with high power pulsed laser at high repetition rate. As pin-on-disc measurements show, laser nanotexturing not only lowers the friction coefficient of the graphite coating, but also eliminates the run-in phase and significantly reduces wear in dry conditions. In addition, the topography induced by the laser treatment generates an optical effect of iridescence which adds a decorative function. These first result open possibilities to develop a new type of graphite coating modified by laser pulses for application on 2D or 3D products with sizes in the order of mm2 to a few cm2. These are first results, further improvement are expected via appropriate texture patterns and doping of the carbon target. Under wet condition, microchannel with heights in the nanometer range between are expected to be beneficial for storing lubricant.

For many applications in the field of cutting tools or watchmaking, the need to develop new solutions in order to improve the lifetime and performances of the components requires new approaches and solutions. In a joint preliminary study between the Berner Fachhochschule (BFH) and the Haute Ecole ARC (HE-ARC), promising results have been achieved with nanotextured carbon layers produced using a hybrid technology. These coatings on steel substrates were obtained in two steps. First, a carbon coating is deposited by standard magnetron sputtering technology using a graphite target at HE-ARC. In a second step, the coating is treated at BFH with high power pulsed laser at a repetition rate of 100kHz which modifies the surface roughness and induced a nanotexture. The pin-on-disc measurements performed in dry conditions on the textured graphite coating against a 100Cr6 steel ball showed that laser nanotexturing not only lowers the friction coefficient by 20-50% down to values between 0,10 - 0,18 but also eliminates the run-in phase and reduces wear by 50-100%. This first study opens many possibilities to develop a new type of carbon-based coatings on 2D or 3D surfaces with sizes in the order of mm2 to several cm2 with modification by laser pulses for improved tribological performances. Since the coating material is carbon, the maximum service temperature is around 400°C. These are first results; further optimization of the texture patterns is expected. Under lubricating condition, nanochannels with heights in the order of ~100nm are expected to be beneficial for storing of oil or water.