Polyetheretherketone (PEEK) is a Federal and Drug Administration (FDA) approved biomaterial that has been used as an orthopedic implant material due to its inherent properties. Laser etching has become a popular means to create identication markers on the individual implants as required by the FDA. The interaction of laser energy with polymeric materials could potentially cause changes in the material's biocompatibility and mechanical properties. The objective of this study was to determine the effect of laser energy on the biocompatibility and mechanical properties of implantable PEEK by measuring contact angle, micro-tensile testing, nite-element modeling (FEM), and biocompatibility testing according to International Organization for Standardization (ISO) 10993 for cytotoxicity. The results of the study showed that the etching characteristics were mostly in by the laser power and the laser pulse spacing. The mechanical properties were degraded by the laser and the tensile strength of the material was decreased by 50% is some cases. The laser, however, did not affect the biocompatibility. The biocompatibility testing of the material showed no cytotoxic effect using an agar overlay method. The contact angle measurements demonstrated that the laser etching produced a hydrophobic effect to the surface. The FEM model demonstrated a good correlation between the laser power and the vaporization of the PEEK material. The results of the study showed the effect of laser energy on biocompatibility and mechanical properties.

<p>Patterning of multi crystalline silicon Solar cell is prepared with photolithography etching. Electroless plating is used to get metallization of Nickel contacts. SEM analysis of Nickel deposition and measurement of contact resistance for series and shunt resistance is done. To increase the fill factor, the screen printed electrodes are subjected to different firing temperatures there by increasing the efficiency of solar cell. Nickel-silicide formation at the interface between the Silicon and Nickel enhances stability and reduces the contact resistance, resulting in higher energy conversion efficiency.</p><p> </p>

Patterning of multi crystalline silicon Solar cell is prepared with photolithography etching. Electroless plating is used to get metallization of Nickel contacts. SEM analysis of Nickel deposition and measurement of contact resistance for series and shunt resistance is done. To increase the fill factor, the screen printed electrodes are subjected to different firing temperatures there by increasing the efficiency of solar cell. Nickel-silicide formation at the interface between the Silicon and Nickel enhances stability and reduces the contact resistance, resulting in higher energy conversion efficiency.

This research details an investigation into processes employing laser technology to create design-led three-dimensional textiles. An analysis of historical and contemporary methods for making three-dimensional textiles categorises these as processes that construct a three-dimensional textile, processes that apply or remove material from an existing textile to generate three-dimensionality or processes that form an existing textile into a three-dimensional shape. Techniques used in these processes are a combination of joining, cutting, forming or embellishment. Laser processing is embedded in textile manufacturing for cutting and marking. This research develops three novel processes: laser-assisted template pleating which offers full design freedom and may be applied to both textile and non-textile materials. The language of origami is used to describe designs and inspire new design. laser pre-processing of cashmere cloth which facilitates surface patterning through laser interventions in the manufacturing cycle. laser sintering on textile substrates which applies additive manufacturing techniques to textiles for the generation of three-dimensional surface patterning and structures. A method is developed for determining optimum parameters for laser processing materials. It may be used by designers for parameter selection for processing new materials or parameter modification when working across systems.

L’avènement des technologies lasers femtoseconde utilisant une fibre optique comme milieu amplificateur incite les industriels à se renseigner sur cette technologie. Dans ce contexte, et dans le cadre du projet Futures et Ruptures, cette thèse se propose de caractériser une nouvelle source femtoseconde, le Tangerine d’Amplitude Systèmes. Utilisant les capacités de ce laser, et avec la collaboration d’IREPA LASER, nous feront une étude comparative avec les lasers femtoseconde déjà existant en s’appuyant sur l’état de l’art, l’optique non-linéaire et quelques simulations d’ablation. L’amélioration des procédés d’usinage pour des applications industrielles nous permettra de modifier et compléter nos connaissances dans l’usinage de différents matériaux tout en montrant les qualités de cette nouvelle technologie. Enfin, une application de miniaturisation de dispositifs électronique pour le domaine du biomédical nous permettra d’utiliser toutes les connaissances acquises et de mener à bien ce projet. / Surgical procedures are moving increasingly toward minimally invasive techniques because these techniques offer great comfort to the patient, a short recovery time and are reasonably-priced. As part of this thesis, it is proposed to study the integration of micrometer-sized sensors directly into needles for example. The PhD student will study the process of laser-matter interaction for new nano and femtosecond sources which should be optimized in order to develop a machining technique of surgical instruments in order to incorporate the sensors. The aim of the thesis is the demonstration of the feasibility of developing the technique of laser etching for the integration of sensors into millimeter-sized needles as well as tests in real conditions. Multiple lasers will be used; The Tangerine laser from ‘Amplitude Systèmes’ with the well know Ti:Sa laser. His work there will be to upgrade the laser up to its best capacity both in terms of fluence or accuracy and in terms of software and its ease of use. The ablation of the silicon from the rear of the electronic chip to the edge of the photodetector in order to carry the light and energy supply all 3D Hall effects micro-magnetors will be the main purpose of the PhD student. He will highlight differences between two femtosecond laser as thermally affected area or ablation rate and will choose which one is able to achieve our goal.

La faible densité et les propriétés mécaniques remarquables des composites polymères en font des matériaux de choix pour remplacer les métaux. Cependant, leurs propriétés physicochimiques rendent leurs surfaces peu adhésives pour divers types de revêtements. Pour améliorer l’adhérence de revêtements métalliques sur des substrats de PEEK, et pour mieux comprendre les mécanismes de l’adhésion, les propriétés de surface du matériau ont été modifiées par des procédés physiques en voie sèche.D’une part, cette étude montre que les traitements par plasma oxydants (à basse pression, ou à pression atmosphérique) permettent d’améliorer la mouillabilité de la surface et l’adhérence de revêtements métalliques, par l’augmentation de la polarité de la surface, quantifiée par XPS. D’autre part, cette étude montre que l’ablation laser infrarouge à impulsion femtoseconde permet la gravure d’un motif dense, induisant de meilleures tenues mécaniques de l’assemblage. Enfin, cette étude montre que la modification de la chimie et de la topographie combinées améliore davantage ce potentiel d’adhérence.Le but de cette étude est d’ouvrir une voie vers un modèle décrivant les mécanismes de l’adhésion, influencés par la chimie de surface et la géométrie d’un motif, en s’appuyant sur un modèle mécanique permettant de décrire la dynamique des contraintes se propageant au travers de l’interface, en tenant compte des propriétés mécaniques des matériaux. / Thanks to their low densities and good mechanical properties, polymer composites are good candidates for metal alloys substitutes. However, their physicochemical properties limit their adhesion potential towards several types of coatings. In order to improve metallic thin films adhesion on PEEK substrates, and to better comprehend adhesion mechanisms, dry-phase methods have been used to alter the surface properties of the material.First, this study shows that oxidative plasma treatments (at low or at atmospheric pressure) improve the wettability and the practical adhesion of metallic coatings, by an increase of the polar component of the surface, as measured by XPS. Second, this study shows that dense patterns etched by an infrared femtosecond laser allow good practical adhesion of the metallic thin films on the substrate. Finally, this study shows that the modification of both surface chemistry and the surface topography at the same time further improves the practical adhesion of the metallic thin films.The goal of this study is to propose a route towards a model describing the combined influence of surface texture and chemistry, with the support of a mechanical model describing the dynamics of the stress dissipation through the interface while taking into account the mechanicals properties of the interfacial materials.

Ce travail de thèse a permis de montrer que la résolution latérale de gravure de lasers proches infrarouges nanosecondes pouvait être réduite en faisant passer le faisceau à travers des microbilles de verre ou des fibres de silice à embouts façonnés de telle manière à générer des jets photoniques. Sur du silicium la taille de gravure peut être réduite d’un facteur 44 comparée à celle d’une gravure directe sans jet photonique. Les densités de puissances atteintes permettent même d’envisager de graver le verre avec ce type de laser malgré sa très faible absorption à ces longueurs d’onde. Pour la première fois nous avons montré la possibilité d’obtenir des jets photoniques en sortie de fibre optique à embout façonné. Nous avons montré leur capacité à graver le silicium à l’échelle du micron et ce avec un laser proche infrarouge nanoseconde. La possible utilisation de fibres optiques est une condition clairement décisive à la réalisation d’un réel procédé laser capable de graver des motifs complexes et de façon répétée. / This work has shown that the lateral resolution etching using near infrared lasers nanoseconds could be reduced by passing the beam through a glass microsphere or a silica fibers with spheroid shape in such a way to generate photonic jets. Etching on silicon size with a glass microsphere can be reduced by a factor of 44 compared to that of a direct etching without photonic jet. Powers reached densities allow even consider burning the glass with this type of laser, despite its very low absorption at these wavelengths. For the first time we have shown the possibility of obtaining photonic jets coming-out of a spheroid-tip of fiber optic. We also have shown the ability to etch silicon at the micron scale using the near infrared nanosecond laser. The possible use of optical fibers is clearly a decisive condition for the realization of a laser capable of etching process real intricate designs and repeatedly.