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Batooli L.,Ecole Polytechnique Federale de Lausanne | Maldonado S.G.,Ecole Polytechnique Federale de Lausanne | Judelewicz M.,Gersteltec Sarl | Mischler S.,Ecole Polytechnique Federale de Lausanne
Micromachines | Year: 2015

Tribology of SU-8 polymer is increasingly relevant due to bursting use of this material in a variety of applications. This study is directed towards introduction and investigation of a novel self-lubricating composite of an ionic liquid (IL) in SU-8. The new material can be utilized for fabrication of lubricating polymer coating with tunable surface properties or SU8-made elements for microelectromechanical systems (MEMS) with enhanced tribological performance. It is shown that addition of IL drastically alters water affinity of the composite while UV patternability remains unmodified. A lower coefficient of friction and wear has been obtained for two investigated compositions with 4 and 10 wt % ionic liquid. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source


Mapelli A.,Ecole Polytechnique Federale de Lausanne | Mapelli A.,CERN | Gorini B.,CERN | Haguenauer M.,Ecole Polytechnique - Palaiseau | And 3 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

A novel liquid scintillation detector with high spatial resolution is being developed with standard microfabrication techniques. It consists of a dense array of scintillating waveguides obtained by filling microfluidic channels with an organic liquid scintillator and optically coupled to a pixellated photodetector. Such a microfluidic device can be designed and processed to meet the requirements of a wide range of applications like medical imaging, homeland security and high-energy physics. High-spatial resolution miniaturized detectors as well as large-area detectors can easily be fabricated. The fabrication process of a prototype detector and experimental results are presented in this paper. © 2009 Elsevier B.V. All rights reserved. Source


Mapelli A.,Ecole Polytechnique Federale de Lausanne | Mapelli A.,CERN | Gorini B.,CERN | Haguenauer M.,Ecole Polytechnique - Palaiseau | And 5 more authors.
Sensors and Actuators, A: Physical | Year: 2010

A novel type of particle detector based on scintillation, with precise spatial resolution and high radiation hardness, is being studied. It consists of a single microfluidic channel filled with a liquid scintillator and is designed to define an array of scintillating waveguides each independently coupled to a photodetector. Prototype detectors built using an SU-8 epoxy resin have been tested with electrons from a radioactive source. The experimental results show a light yield compatible with the theoretical expectations and confirm the validity of the approach. © 2010 Elsevier B.V. All rights reserved. Source


Mapelli A.,Ecole Polytechnique Federale de Lausanne | Mapelli A.,CERN | Gorini B.,CERN | Haguenauer M.,Ecole Polytechnique - Palaiseau | And 3 more authors.
IEEE Transactions on Nuclear Science | Year: 2011

A new type of scintillation detector is being developed with standard microfabrication techniques. It consists of a dense array of scintillating waveguides obtained by coupling microfluidic channels filled with a liquid scintillator to photodetectors. Easy manipulation of liquid scintillators inside microfluidic devices allow their flushing, renewal, and exchange making the active medium intrinsically radiation hard. Prototype detectors have been fabricated by photostructuration of a radiation hard epoxy resin (SU-8) deposited on silicon wafers and coupled to a multi-anode photomultiplier tube (MAPMT) to read-out the scintillation light. They have been characterized by exciting the liquid scintillator in the 200 micrometers thick microchannels with electrons from a ° Sr yielding approximately 1 photoelectron per impinging Minimum Ionizing Particle (MIP). These promising results demonstrate the concept of microfluidic scintillating detection and are very encouraging for future developments. © 2011 IEEE. Source


Mionic M.,Ecole Polytechnique Federale de Lausanne | Jiguet S.,Gersteltec Sarl | Judelewicz M.,Gersteltec Sarl | Karimi A.,Ecole Polytechnique Federale de Lausanne | And 2 more authors.
Physica Status Solidi (B) Basic Research | Year: 2010

Multiwalled carbon nanotubes (MWCNTs)/SU8 composites have been produced to enhance the mechanical properties of SU8 photoresist. We have studied the influence of SU8 solvent on the structural homogeneity of composites through nanoindentation testing. It is found that acetone and propylene glycol methyl ether acetate (PGMEA) are very suitable solvents to prepare MWCNTs/SU8 composites with significant increase of the Young's modulus (EY). The highest increase of EY in respect to the parent material of 104% was obtained with acetone as solvent. It was noticed that the remaining solvent in the composite influences strongly EY, as well. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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