Co-axial capillaries microfluidic device for synthesizing size- and morphology-controlled polymer core-polymer shell particles

An easy assembling-disassembling co-axial capillaries microfluidic device was built up for the production of double droplets. Uniform polymer core-polymer shell particles were synthesized by polymerizing the two immiscible monomer phases composing the double droplet. Thus poly(acrylamide) core-poly(tripropylenglycol-diacrylate) shell particles with controlled core diameter and shell thickness were simply obtained by adjusting operating parameters. An empirical law was extracted from experiments to predict core and shell sizes. Additionally uniform and predictable non-spherical polymer objects were also prepared without adding shape-formation procedures in the experimental device. An empirical equation for describing the lengths of rod-like polymer particles is also presented

Microfluidic synthesis and assembly of reactive polymer beads to form new structured polymer materials

Monodisperse and size-controlled polymer particles were produced without surfactant or wash-coat from O/W monomer emulsions and ‘‘on the fly’’ polymerization under UV irradiation in a very simple needle/tubing system. The effect of the viscosity of the continuous phase on the size of final particles was investigated. The capillary number ratio was found to be relevant to predict the size of the droplets. A relation between dimensionless numbers predicts particle diameter as a function of the needle inner diameter and both velocity and viscosity ratios of continuous and dispersed phases. A functional comonomer was incorporated in the monomer phase so as to obtain polymer microparticles bearing reactive groups on their surface. Polymer beads necklaces were thus formed by linking polymer particles together

Auto-assemblage de copolymères à blocs à haute force de ségrégation dans une configuration de film mince

Ce manuscrit de thèse porte sur la formation de masques de réseaux denses de nanopiliers ou nanotrous à partir de l auto-assemblage de copolymères à blocs (CPB) à haute force de ségrégation, pour des applications dans la micro-électronique. Des copolymères à blocs, de type ABA, constitués d un bloc central de polydiméthylsiloxane (PDMS) et de deux blocs terminaux de polylactide (PLA) ont été synthétisés par polymérisation par ouverture de cycle. Les caractérisations de deux CPB d intérêt en masse et sous forme de film mince montrent une mesostructure hexagonale sphérique et cylindrique de PLA dans la matrice de PDMS,avec des périodes de 14,3 et 15,5 nm respectivement. Afin de contrôler l organisation des domaines, les autoassemblages des films minces des deux CPB ont été étudiés en fonction de plusieurs facteurs : paramètres de dépôt et post-traitements (exposition à des vapeurs de solvant et recuit thermique). Dans le cas du réseau hexagonal cylindrique, le contrôle des énergies interfaciales entre le film et le substrat de silicium a été obtenu grâce au greffage d une couche de copolymères statistique ayant des blocs chimiquement différent des blocs contenus dans le CPB. Par ailleurs, à des fins industrielles, les mesostructures doivent montrer une organisation à grande échelle (plusieurs micromètres) dépourvue de défauts. Dans cette perspective, l auto-assemblage des CPB a aussi été étudié sur des surfaces à topographie contrôlée (graphoépitaxie) montrant un relief sinusoïdal.This manuscript is related to the formation of high density masks of nanoholes or nanodotsmade from high segregation strength block copolymer (BCP) for applications in the microelectronicindustry. Two block copolymers, ABA type with a polydimethylsiloxane (PDMS) center block and twoterminal polylactide (PLA) blocks, where synthetized by a ring opening polymerization. BCP characterizations inbulk and in thin film show a hexagonal array of PLA spheres and cylinders in a PDMS matrix, with 14,3 and 15,5nm pitches respectively. In order to control the domain organization, thin film BCP self-assembly were studiedin function of several parameters : spin coating process and post-treatments (vapour and thermal annealing). Inthe case of the hexagonal array of cylinders, the control of the interfacial energy between the film and thesilicon wafer has been obtained by grafting a random copolymer layer. Due to their microelectronicapplications, the mesostructures need to be defectless at a large scale (several micrometres). In this way, theself-assembly of one of the two BCP has also been studied by graphoexpitaxy on a sinusoidal surface-reliefgratings.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Structure, morphology and performance relationships of organic photovoltaic devices (the block copolymer approach)

Ce travail se focalise sur l étude de cellules solaires organiques modèles basées sur le mélange de poly(3-hexylthiophène) (P3HT) et de l'ester méthylique de l'acide [6,6]-phényl C61 butyrique (PCBM). La corrélation entre la morphologie de la couche active, les paramètres de mises en œuvre et le rendement photovoltaïque a été soigneusement étudiée afin d obtenir l optimisation de l efficacité de tels dispositifs. Une méthode originale pour contrôler la séparation de phases dans ces mélanges a été proposée et consiste à l'intégration de copolymères blocs comme additifs. Trois copolymères séquencés ont été utilisés en tant qu agents de nanostructuration et/ou d'agents de nucléation. Il a notamment été montré que l'incorporation de P3HT-b-PI permet l'augmentation du nombre de cristallites de P3HT tout en limitant l agglomération du PCBM. D'autre part, l'incorporation de P3HT-b-P4VP dans les mélanges de P3HT:PCBM a permis de contrôler l'orientation des cristallites de P3HT, améliorant par ce fait le transport de charge dans les dispositifs.This work investigates organic solar cells made of a blend of polymeric materials based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as model system. The correlation between the photovoltaic active layer morphology and the performance of the organic solar cell is thoroughly investigated. The chosen method for controlling phase separation in the polymeric blends is to incorporate block copolymers as additives. Three systematically selected block copolymers were used as nanostructuring and/or nucleating agents. Indeed, the incorporation of P3HT-b-PI induces the increase in the number of P3HT crystallites as well as suppresses the growth of PCBM aggregates. On the other hand, the incorporation of P3HT-b-P4VP into P3HT:PCBM decreases the crystallization of P3HT but increases its face-on orientation, a requirement for an enhanced charge transport in organic PV devices.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Synthèse et caractérisation d'encres électrophorétiques pour la réalisation de papier électronique couleur

Cette thèse s intéresse principalement à la réalisation de nouvelles encres électrophorétiques pour les applications de type papier électronique couleur. Une méthode simple et peu contraignante basée sur la polymérisation en dispersion a été développée, permettant de réaliser de manière contrôlée et en milieu peu polaire des particules de polymère chargeables positivement ou négativement. Puis, grâce à ce nouvel outil, des particules électrophorétiques hybrides ont été synthétisées à partir de pigments inorganiques et caractérisées sous champ électrique. Enfin une nouvelle solution pour aller vers des dispositifs couleur a été proposée et la fabrication d un démonstrateur test a été abordée.The effective sharing of information is a key parameter in our actual society. Electronic paper based on the controlled motion of electrophoretic particles appears thus promising since it combines the advantages of the usual paper (flexibility, reflective display) and the capacity to refresh information on the same support like the more common LCD or OLED technologies. Electrophoretic inks are composed of coloured charged particles which migrate under an electrical field between two electrodes. Depending of the position of the particles on the front plane, the colour on the screen can be tuned. The design of electrophoretic particles based on pigment or dyed polymer and their integration in electronic devices were successfully achieved during the last decade but are still limited to a two colour-electrophoretic system. Up to date the majority of these particles were synthesized in aqueous media and the electrophoretic mobility was achieved by a ionic stabilizer or by a polyelectrolyte surfactant. Moreover the final electrophoretic particles incorporated in the electronic devices have to be dispersed in an organic media (paraffin oil) in order to achieve the desired stability of the display and thus leads to a large variety of problems during the phase exchange process.In this work our goals were to rationalize and improve the ink synthesis as well as to design electrophoretic inks with the full colour panel in order to realize the next generation of electrophoretic displays. We performed the particle synthesis by using an organic dispersion technique in aliphatic hydrocarbon solvents leading to chargeable electrophoretic particles with a good size control over a large range (from 75nm to 20 m) and a good stability. In order to obtain the full color panel, the encapsulation of several inorganic pigments was achieved by using the same technique and the electrophoretic behaviour of the resulting inks was characterized in a cell specially designed for electrophoretic measurements in organic media.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Enhancing the ferroelectric performance of P(VDF-co-TrFE) through modulation of crystallinity and polymorphism

The functional properties of P(VDF-co-TrFE) are strongly dependent on its structure, which, in turn, depends on processing conditions applied. In this work we investigate the P(VDF-co-TrFE) processing structure-function relationships, in order to find the thermal conditions that result in optimum ferroelectric performance in thin film configuration. Our results show that annealing temperature affects mostly the remnant polarization value, P, while annealing time has a severe effect on the coercive field, E-c, An optimized ferroelectric functionality, in terms of high P-r of about 90 mC/m(2) and low E-c of 50 MV/m, is achieved and rationalized through structural analysis by means of GIWAXS. The best performing structure exhibits a high degree of crystallinity, a preferential orientation of the crystallites with the polymer chains parallel to the substrate and the occurrence of three ferroelectric phases. A deconvolution study demonstrates the presence of a moderately unstable ferroelectric phase that is designated to facilitate ferroelectric switching. Our findings show that a single step of 15 min annealing at 135 degrees C leads to high performance P(VDF-co-TrFE) structure, proving that the 2 h-long annealing step that is traditionally applied is not necessary. (C) 2018 Elsevier Ltd. All rights reserved.</p

Synthèse de copolymères de type polymère semi-conducteur-bloc-polymère hydrosoluble (application à la dispersion de nanotubes de carbone)

Cette thèse porte pour l'essentiel sur la synthèse de copolymères à blocs bien définis composés au moins d'un bloc polymère semi-conducteur et d'un segment hydrosoluble pour être utilisés comme agents dispersants de nanotubes de carbone (NTCs) dans des milieux aqueux. Des copolymères de différentes masses molaires ont été synthétisés en suivant des procédés de polymérisation sans métaux et l influence de la fraction volumique de la partie hydrosoluble a été étudiée au regard de leur solubilité en milieux aqueux. La capacité de ces copolymères à s'organiser ou s'auto-assembler tant en solution qu'en film a été examinée. Enfin, des dispersions de NTCs avec ces copolymères ainsi que leurs films obtenus par différents types de dépôts ont été réalisés et caractérisés pour déterminer notamment leurs caractéristiques électro-optiques.Our work focused on the synthesis of well-defined copolymers constituted with at least a conductive polymer segment along with hydrophilic moieties in order to disperse CNTs in aqueous media. Using metal free polymerizations, copolymers with different molecular weights were synthesized in order to study the influence of the hydrophilic part on these materials. Besides the self-assembly behavior of these copolymers, both in bulk and in solution, were addressed. This type of copolymers were successfully used to disperse both single and multi wall carbon nanotubes. Electrical and optical characteristics of the dispersions together with their films will also be discussed.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Large area Al2O3–Au raspberry-like nanoclusters from iterative block-copolymer self-assembly

Large area Al2O3–Au raspberry-like nanoclusters and other complex structures have been created by iterative block-copolymer self-assembly, paving the way to a new generation of on-demand metallic architectures