Abstract Determining the prebiotic potential of softwood hemicellulose. Other members of the jury Ana Paula DUARTE, Professor, University of Beira Interior (Portugal) ♦♦ Maija TENKANEN, Professor, University of Helsinki (Finland) ♦♦ Pauline ANTON-GAY, Associate Professor, UniLaSalle, Beauvais ♦♦ Claire BOISSET-HELBERT, Research Engineer, Cermav
December 5, 2017 - Materials, Mechanical, Civil Engineering, Electrochemistry[Thesis online] Ph.D. title
Controle of conducting partern formation by inkjet printing: multi-scale control of material transfer in nanometric suspensions.
This thesis focuses on the understanding of the mechanisms involved in the inkjet printing of silver nanoparticles-based inks in order to optimize the manufacturing of thin (width <100 μm) conductive tracks with high and homogeneous performances. Inkjet printing can be divided into several phases: the ejection of picovolumetric droplets, the impact on the substrate, the spreading and the drying. The drying phase is a complex phase prone to particle migration phenomena such as coffee ring effect. This phenomenon, due to the capillary flow which implies a movement from the center to the edges of the drop, drives most of the suspended particles towards the edges of the printed patterns. The aim of this work is to describe precisely and understand the mechanisms which operate and lead to the transfer effects in order to limit or even eliminate them and guarantee the production of performing and homogenous fine conductive lines. To achieve this objective, three paths of investigation were developed. A first axis deals with the study of the different phases of the droplet generation process. Parameters impacting the dried droplet morphology are identified and optimized with a focus on substrate temperature. Four geometrical indexes are designed to characterize quantitatively the dried droplet profile homogeneity. A second axis specifically studies the drying phase of picovolumetric droplet in order to understand the phenomena occurring during this phase. A modelling of droplet drying is set up in order to understand the forces influencing the matter transport. Finally, a last axis studies the print of thin conductive lines composed of several printed droplets partially superimposed. Correlations between line morphology, droplet morphology and electrical conductivity are established in order to produce optimized systems.
December 1st, 2017 - Fluid Mechanics, Energy, Processes[Thesis online] Ph.D. title Printing and selective sintering of metal based inks on paper. Optimization of electrical properties of RFID-HF loops for industrial production. Supervision Julien BRAS, Associate Professor HDR, Grenoble INP-Pagora / LGP2 ♦♦ Céline MARTIN, Associate Professor, Grenoble INP-Pagora / LGP2 Abstract This project consists to develop and study new hybrid structures based on nanocelluloses and stimuli-responsive polymers, in particular, thermo-responsive polymers. Nanocelluloses - nanoparticles extracted from cellulose - exist in two forms: cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF). This study focused on the design of CNC hydrogels with stimuli-responsive polymers. Several thermo-responsive polymers have been used for their biocompatibility and lower critical solution temperature (LCST) close to body temperature. This work consisted of preparation of systems using the principles of green chemistry, the rheological study of these thermo-sensitive hydrogels, and the development of smart applications for these unique biomaterials. Through the use of state of the art technologies (SANS, SAXS), physicochemical interactions between the polymers and CNC have been studied. The use of block copolymers made it possible to create CNC-based hydrogels with specific rheological properties: liquid at ambient temperature to gel at body temperature. These hydrogels can be used in the creation of injectable systems for biomedical applications, as well as thermosensitive surfaces. Other members of the jury Bernard CATHALA, Research Director, INRA, Nantes ♦♦ Wim THIELEMANS, Professor, Université catholique de Louvain, Belgium ♦♦ Emily CRANSTON, Professor, McMaster University, Canada ♦♦ Frédéric BOSSARD, Professor, LRP, Grenoble ♦♦ Bruno JEAN, Researcher, Cermav, Grenoble ♦♦ Frédéric PIGNON, Research Director, LRP, Grenoble
November 16, 2017 - Materials, Mechanical, Civil Engineering, Electrochemistry Ph.D. title Industrial applications of functional nanocelluloses. Supervision Julien BRAS, Associate Professor, Grenoble INP-Pagora / LGP2 ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 Abstract The aim of this work is to implement new properties to a paper based material via the use of functional nanocelluloses. Nanocelluloses are nanoparticles extracted from wood and distinguished in two categories: Cellulose Nanofibrils (CNF) and Cellulose Nanocrystals (CNC). This work has only been carried out with CNF. The chemical reactivity of CNF was used to functionalize them with organotrialkoxysilanes. The entangled network and highly viscous suspension of CNFs was also used to synthesize silsesquioxane particles with limited size to impart (super)hydrophobic and antimicrobial properties. Knowledge obtained through the study of model CNF films was then applied to paper based material coating. The functional CNF were evaluated for its use in an antimicrobial, anti-adherent, greaseproof or superhydrophobic paper surface. Other members of the jury Gilles SEBE, Associate Professor, ENSCBP, Bordeaux ♦♦ Elisa ZENO, Research Engineer, Centre Technique du Papier, Grenoble ♦♦ Didier LEONARD, Professor, Université Lyon I ♦♦ Monika ÖSTERBERG, Professor, Aalto University, Finland
October 6, 2017 - Fluid Mechanics, Energy, Processes Ph.D. title Towards an integrated Point-of-Care diagnostic device: use of capillarity as well as thermoforming and screen printing processes. Supervision Didier CHAUSSY, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Naceur BELGACEM, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Jean BERTHIER, Research Engineer, CEA, Grenoble Abstract Developments of microfluidics (the study of flows at the sub-millimetric dimensions) have made possible the integration of most of the macroscopic functions of laboratory fluidic systems in a miniaturized system, thus realizing a lab on a chip. This allows the conception of low cost, sensitive and efficient medical diagnostic device usable outside of a medical infrastructure. Such devices are called Point-of-Care systems. The design and fabrication of such devices requires an elaborated and coherent integration that takes into account all the constraints imposed by the targeted final application. The work reported here, and performed during the PhD internship, is focused on the study of the concept and development of the integration of a PoC device based on the isothermal LAMP (Loop mediated AMPlification) reaction for the molecular analysis of DNA. In order to offer a cheap and easily industrialized system, we investigate the use of paper as the chip material and thermoforming as the mean to build the channels. These two techniques are currently used in the industry and their adaptation to the fabrication of such devices is easy and low-cost. In order to perform a LAMP reaction, specific functions such as a heating and a detection system are required. The integration of these functions was carried out using screen printing technology. Heating is done by Joule effect using a layer of carbon-based conductive ink. Detection is performed by a potentiometric method, using polyaniline-covered electrodes. It is shown that this approach is compatible with integration when the screen-printing layers are superposed. Besides they can be printed before thermoforming, resulting in a highly integrated system. Other members of the jury Stéphanie BRIANÇON, Professor, Université Claude Bernard Lyon 1 ♦♦ Chantal FOURNIER-WIRTH, Research Director, ESF Pyrénées-Méditerranée, Toulouse ♦♦ Jean-Christophe BARET, Professor, Université de Bordeaux
September 29, 2017 - Materials, Mechanical, Civil Engineering, Electrochemistry[Thesis online] Ph.D. title Use of lignocellulosic materials and 3D printing for the elaboration of conductive carbon strutures. Supervision Davide BENEVENTI, CNRS Research Director, Grenoble INP-Pagora / LGP2 ♦♦ Didier CHAUSSY, Professor, Grenoble INP-Pagora / LGP2 ♦♦ Philippe GROSSEAU, Research Director (École des Mines, Saint-Étienne) Abstract In this thesis, electrically conductive and mechanically resistant carbon structures were elaborated by 3D printing and subsequent pyrolysis using microfibrillated cellulose, lignosulfonate and cellulose powder (MFC/LS/CP) blends. The processability of MFC/LS/CP slurries by 3D printing was examined by rheological tests in both steady flow and thixotropic modes. The printed MFC/LS/CP pastes were selfstanding, provided a high printing definition and were proved to be morphologically stable to air drying and the subsequent pyrolysis. Pyrolysis at a slow rate (0.2°C/min) to a final temperature in the range of 400-1200°C was used to manufacture MFC/LS/CP carbons. The TGA/DTG was applied to monitor the thermal degradation of MFC/LS/CP materials in blends as well as in a separated form. The resulting carbons were further characterized in terms of morphology, microstructure and physical properties (such as density, electrical conductivity and mechanical strength). At 900°C, MFC/LS/CP carbons displayed a high electrical conductivity of 47.8 S/cm together with a low density of 0.74 g/cm3 as well as an important porosity of 0.58. They also achieved an elastic modulus maximum of 6.62 GPa. Such interesting electrical and mechanical properties would lead to a promising application of MFC/LS/CP- derived biocarbons in energy storage devices as electrode materials in close future. Other members of the jury Pascaline PRÉ, Professor, École des Mines, Nantes ♦♦ Sylvain SALVADOR, Professor, École des Mines, Albi ♦♦ Salaheddine SKALI-LAMI, Associate Professor HDR, Université de Lorraine
July 12, 2017 - Fluid Mechanics, Energy, Processes Ph.D. title Printing and selective sintering of metal based inks on paper. Optimization of electrical properties of RFID-HF loops for industrial production. Supervision Nadège REVERDY-BRUAS, Associate Professor, Grenoble INP-Pagora / LGP2 ♦♦ Denis CURTIL, Research Engineer, Grenoble INP-Pagora / LGP2 ♦♦ Mohamed SAADAOUI, Associate Professor, École des Mines, Saint-Étienne Abstract This work examines the potential of a very smooth paper for the mass production of printed RFID-RF tags. Characterizations on PowerCoat HD paper demonstrate high temperature tolerance and verv low roughness. lt thus represents a serious alternative to the use of polymeric films (PET, PEN, Pl, etc.) enabling the electrical performance of metallic conductive inks to be fully developed. Two industrial printing processes have been considered: flexography and screen printing, and their use were discussed for the printing of low-cost electronic devices. Moreover, the electrical performances of commercial silver based inks are studied according to the size of their particles. lndeed, the use of metal particles at the nanometric scale can facilitate the activation of the atomic diffusion mechanisms, thus improving the physical contact between the particles and promoting electrical conduction. ln parallel, microparticles inks are cheaper and their conditions of use less restrictive. ln any case, the coalescence of the metal particles after printing cannot be initiated without a thermal sinter ing treatment. Sintering is usually carried out in an oven or hot air tunnel, the temperature must therefore remain below the tolerance of the substrate. This leads to limited electrical performances for long process duration of several minutes. ln order to take into account the industrial constraints of largescale production and to achieve the best electrical performance in a short time, one of the main explored research areas is the deployment of emerging near- infrared (NIR) and intense pulsed light (IPL) photonic technologies. These latter are based on the absorption of light energy by the ink film thus causing rapid heating. The important absorption differential between the inks and the substrate allows high heating selectivity which makes it possible to limit the degradation of the substrate while the ink temperatures may be greater than 300 ° C. For each sintering process, the influence of the various parameters on the final electrical performance has been studied by using an in situ resistance monitoring, allowing sampling frequency up to 250 kHz. Finally, RFID-HF loops were printed, sintered under previously optimized conditions and then characterized. An estimate of the production costs was carried out in order to distinguish the contributions related to the ink, the substrate and the silicon chip. The obtained results demonstrate the potential of PowerCoat HD paper, coupled with flexographic roll-to-roll printing and near-infrared technology, enabling the large-scale production of RFID-HF tags at a material cost of the order of 5 euros cents. Other members of the jury Philippe DELAPORTE, CNRS Research Director, Aix-Marseille Université ♦♦ Hélène DEBEDA, Associate Professor, Université de Bordeaux ♦♦ Damien DELERUYELLE, Professor, INSA Lyon ♦♦ Tan-Phu VUONG, Professor, Grenoble INP-Phelma ♦♦ Bernard RATIER, Professor, XLIM, Limoges
June 27, 2017 - Materials, Mechanical, Civil Engineering, Electrochemistry[Thesis online] Ph.D. title A matrix based on stimulable nanocellulose for differentiated growth of cells. Supervision Julien BRAS, Associate Professor, Grenoble INP-Pagora / LGP2 Other members of the jury Catherine PICART, Professor, Grenoble INP ♦♦ Kristin SYVERUD, Professor, NTNU (Norway) ♦♦ Tanja ZIMMERMANN, Research Director, EMPA (Switzerland) ♦♦ Claire ROME, Associate Professor, Université Grenoble Alpes ♦♦ Johan FOSTER, Associate Professor, Virginia Tech (USA)
February 14, 2017 - Materials, Mechanical, Civil Engineering, Electrochemistry Ph.D. title Development of new barrier materials using microfibrillated cellulose. Supervision Alain DUFRESNE, Professor, Grenoble INP-Pagora / LGP2 ♦♦ David GUÉRIN, Manager Research Unit, Centre Technique du Papier, Grenoble Abstract This study takes place in a context of development of paper-based barrier packaging materials, using microfibrillated cellulose (MFC) that displays renewability, recyclability and biodegradability. Two strategies have been investigated: the wet lamination of a MFC barrier layer on board, and the use of MFC as additive in a water-based barrier coating colour. The promising use of MFC for the formation of barrier layers has been demonstrated in both cases. The wet lamination of MFC on board led to good oxygen and grease barrier properties, using highly fibrillated MFC. The board-MFC complex presented a strong adhesion after drying, without requiring glue. For composite barrier coating, in order to obtain low viscosity suspensions leading to high barrier layers, the use of highly fibrillated MFC mixed with a fully-hydrolysed poly(vinyl alcohol (PVOH) with a low degree of polymerisation has been preferred. The addition of MFC in PVOH demonstrated its potential for improving the drying behaviour of water-barrier barrier coating colours. The combined use of MFC and layered silicates evidenced a synergistic effect on their dispersion in a PVOH solution, leading to an improved water vapour barrier while avoiding the formation of aggregates that otherwise damage the oxygen barrier. The work contributes to demonstrate the potential of MFC to be used for the formation of barrier layers, paving the way for the development of more sustainable barrier packaging materials. Other members of the jury Hélène ANGELLIER-COUSSY, Associate Professor, Université de Montpellier ♦♦ Yves GROHENS, Professor, Université Bretagne Sud ♦♦ Jose-Maria LAGARON, Research Director, Consejo Superior de Investigaciones Científicas, Espagne ♦♦ Laurent HEUX, CNRS Research Director, Université Grenoble Alpes
Wilson PIRES FLAUZINO NETO
January 26, 2017 - Materials, Mechanical, Civil Engineering, Electrochemistry[Thesis online] Ph.D. title
Morphological investigation of cellulose nanocrystals and nanocomposite applications
Since this thesis presents two independent studies on cellulose nanocrystals, the abstract was divided in two sections referring to chapters II and III, respectively.Comprehensive morphological and structural investigation of cellulose I and II nanocrystals prepared by sulfuric acid hydrolysis Cellulose nanocrystals (CNCs) were produced from eucalyptus wood pulp using three different methods: i) classical sulfuric acid hydrolysis (CN-I), ii) acid hydrolysis of cellulose previously mercerized by alkaline treatment (MCN-II), and iii) solubilization of cellulose in sulfuric acid and subsequent recrystallization in water (RCN-II). The three types of CNCs exhibited different morphologies and crystal structures that were characterized using complementary imaging, diffraction and spectroscopic techniques. CN-I corresponded to the type I allomorph of cellulose while MCN-II and RCN-II corresponded to cellulose II. CN-I and MCN-II CNCs were acicular particles composed of a few laterally-bound elementary crystallites. In both cases, the cellulose chains were oriented parallel to the long axis of the particle, although they were parallel in CN-I and antiparallel in MCN-II. RCN-II particles exhibited a slightly tortuous ribbon-like shape and it was shown that the chains lay perpendicular to the particle long axis and parallel to their basal plane. The unique molecular and crystal structure of the RCN-II particles implies that a higher number of reducing chain ends are located at the surface of the particles, which may be important for subsequent chemical modification. While other authors have described nanoparticles prepared by regeneration of short-chain cellulose solutions, no detailed description was proposed in terms of particle morphology, crystal structure and chain orientation. Was provide such a description in the present document.Mechanical properties of natural rubber nanocomposites reinforced with high aspect ratio cellulose nanocrystals isolated from soy hullsCellulose nanocrystals (CNCs) were isolated from soy hulls by sulfuric acid hydrolysis. The resulting CNCs were characterized using TEM, AFM, WAXS, elemental analysis and TGA. The CNCs have a high crystallinity, specific surface area and aspect ratio. The aspect ratio (around 100) is the largest ever reported in the literature for a plant cellulose source. These CNCs were used as a reinforcing phase to prepare nanocomposite films by casting/evaporation using natural rubber as matrix. The mechanical properties were studied in both the linear and non-linear ranges. The reinforcing effect was higher than the one observed for CNCs extracted from other sources. It may be assigned not only to the high aspect ratio of these CNCs but also to the stiffness of the percolating nanoparticle network formed within the polymer matrix. Moreover, the sedimentation of CNCs during the evaporation step was found to play a crucial role on the mechanical properties.