Segmental chain dynamics in polymer blends is a very important topic, not only from a fundamental point of view but also from technological applications. Because of the difficulties in the commercialization of new polymers, industries have turned increasingly towards blending of polymers to optimise their end use (mechanical, rheological) properties. The design of tailor-made materials would be enormously facilitated by the understanding of the blending phenomena at a molecular level. The key question to address is to understand the dynamics of each component of the blend modified by blending? The thesis has systematically studied the effect of multiwalled carbon nanotubes on the chain dynamics, demixing temperature, structural properties and evolution of morphology in a classical miscible polymer blend system (PVDF/PMMA). The thesis comprises of six chapters, Chapter 1 is an introductory chapter that outlines the fundamentals of polymer blends, crystallisation in polymer blends and the basics of dielectric spectroscopy. As one of the rationales of this work is to systematic study whether phase separated in these blends can be used as a tool to develop membrane for water purification. This chapter also gives an overview of the reported studies of ultrafiltration membrane fabrication, factors affecting membrane morphology and flux. In Chapter 2, the materials and methodology used to carry out experiments and the experimental procedures are discussed. Chapter 3 discusses the effect of concentration of PMMA and amine functionalized multiwalled carbon nanotubes (MWNTs) on the crystallisation induced phase separation using FTIR, XRD, POM and shear rheology. Electron microscopy and selective etching confirmed the localisation of MWNTs in the PVDF phase of the blends. Blends with MWNTs facilitated in heterogeneous nucleation manifesting in an increase in crystallisation temperature. The crystallisation induced phase separation in PVDF/PMMA blends was observed to influence the interconnected network of MWNTs in the blends. Chapter 4 discuss the effect of concentration of PMMA and MWNTs on the miscibility and the segmental relaxations was probed in situ by DSC and dielectric relaxation spectroscopy (DRS). The dynamic heterogeneity in the blends as manifested by the presence of an extra relaxation at a higher frequency at or below the crystallisation induced phase separation temperature was also discussed. We found that PVDF/PMMA blend (PVDF ≥ 80 wt%) exhibits three distinct relaxations; αc corresponding to crystalline PVDF, αβ segmental relaxation of PMMA and αm of amorphous miscibility whereas all relaxations overlap and constitute a single broad relaxation in PVDF/PMMA blend (PVDF ≤ 70 wt%). This confirms that there is a certain composition width in this blend wherein three distinct relaxations can be traced. This could due to many reasons like the width of crystal-amorphous interphase in the crystal lamellae, crystal size and morphology is strongly contingent on the concentration of PMMA. Relaxations are not very distinct in presence of MWNTs due to defective spherulites that shift the relaxations towards a higher frequency. Chapter 5 has attempted to tune the microporous morphology of PVDF membranes using crystallisation induced phase separation in PVDF/PMMA blends. As PVDF/PMMA is a melt-miscible blend, the samples were allowed to crystallise and the amorphous PMMA phase, which isolates in the interlamellar or inter-spherulitic regions in the blends, was etched out to generate microporous structures. The pore sizes can be tuned by varying the PMMA concentration in the blends. We observed that 60/40 PVDF/PMMA blends showed larger pores as compared to 90/10 PVDF/PMMA blends. We further modified PVDF membranes by sputtering silver on the surface. The bacterial cell viability was distinctly suppressed (99 %) in silver sputtered membranes. The ICP analysis suggests that slow Ag+ ions release from the sputtered membrane surface assisted in developing antibacterial surface. Our findings open new avenues in designing water filtration membranes and also help in understanding the crystallisation kinetics for tuning pore size in membranes. Chapter 6 summarises the important results of this work. MWNTs act as hetero nucleating agent and specifically interact with PVDF thereby influences the dynamics of PVDF chains. MWNTs can also restrict the amorphous segmental mobility and can influence the intermolecular cooperativity and coupling. The crystallisation induced phase separation in various blends can result in various crystalline morphologies depending on the PVDF concentration. By selectively etching PMMA from the phase-separated blends, microporous morphology can be generated

Le développement d’un procédé de polymérisation en émulsion est complexe de par la nature hétérogène de ce type de réaction. En outre, dans le cas de la polymérisation en émulsion du fluorure de vinylidène, la difficulté est d’autant plus accrue que le monomère est habituellement en phase gazeuse ou supercritique dans les conditions d’intérêt. Or la littérature manque d’informations concernant ce type de procédé de synthèse du PVDF sous une pression comprise entre 30 bar et 90 bar.Ainsi cette thèse a pour objectif de contribuer à une meilleure compréhension des mécanismes cinétiques et de stabilisation intervenants dans la polymérisation radicalaire en émulsion du VDF dans des conditions supercritiques et, plus particulièrement, de fournir des données expérimentales nécessaires à l’élaboration de futurs modèles.Avant même d’entreprendre les études expérimentales, cette thèse s’intéresse d’abord aux aspects d’installation et d’automatisation de l’unité de polymérisation ainsi qu’au démarrage et à l’optimisation du réacteur. Ensuite, plusieurs tests sont réalisés afin de comprendre certaines caractéristiques du latex produit ainsi que certaines propriétés du tensioactif fluoré. Une nouvelle méthode a spécialement été développée afin de suivre le phénomène de coagulation des particules de polymère.Finalement des réactions sont réalisées par lot et en semi-continu et une étude paramétrique des conditions opératoires et de la composition des réactifs est effectuée afin d’évaluer leur impact sur l’évolution de la polymérisation en émulsion. Notamment, le profil de vitesse de polymérisation est obtenu par calorimétrie, à partir d’une approche pratique fondée sur un estimateur d’état en cascade, ainsi que sur la mesure de la consommation de monomère, et sur l’analyse gravimétrique réalisée par prélèvement / The heterogeneous nature of the conventional emulsion polymerization can render the process quite complex. In the case of the emulsion polymerisation of vinylidene fluoride (VDF), the situation is more complicated than for the majority of industrial processes because the monomer is typically either a gas or a supercritical fluid under the polymerization conditions of interest. Given the relatively high pressure required for this process (30bar <P< 90bar), there is a lack of information in the open literature about the VDF emulsion polymerization process.In this sense, this thesis is a contribution to the understanding of the kinetic and stabilization mechanisms that intervene in the free radical emulsion polymerization of vinylidene fluoride (VDF) under supercritical conditions, and more particularly, to the generation of relevant experimental data that can be used for future model developments.Prior to the experimental studies of VDF emulsion polymerization, issues that ranged from the installation and automation of the polymerization unit to the start-up and optimization of the reactor were covered. Later, different tests were performed in order to understand some important features of the produced latex as well as some properties of the fluorinated surfactant. Additionally, a new method to monitor the coagulation phenomena on polymer particles was developed.Finally, reactions were performed using batch and semi-batch mode. The impact of certain compositional changes and reaction conditions on the evolution of the emulsion polymerization was studied. A practical approach was implemented to follow the rate of polymerization using reaction calorimetry. Simultaneous estimations of the evolution of overall heat transfer coefficient and heat of reaction were determined using a high-gain nonlinear cascade state estimator

Ce travail porte sur la modification de matrices polymères à base de fluorure de vinylidene pour permettre leur utilisation en tant que membrane séparatrice dans les supercapacités. Basé sur un procédé d‘irradiation par rayonnement γ, l‘objectif principal était la limitation du gonflement du polymère lorsqu‘il est mis en contact d‘un milieu liquide relatif à l‘application tout en gardant d‘excellentes affinités avec celui-ci. Le processus de base exploité étant la formation et la réaction des radicaux lors de l‘irradiation du polymère, une partie de la thèse a été consacrée à leur étude par résonance paramagnétique électronique (RPE). Un modèle de simulation de spectre RPE a été mis en place pour identifier et quantifier chacune des espèces radicalaires. L‘effet de la dose d‘irradiation, de la durée d‘un recuit et de la nature de la matrice polymère (homo, copolymère) sur la proportion de ces espèces et sur leur réactivité a été évalué. Un lien avec la formation d‘un réseau a été proposé. Une attention particulière a ensuite été apportée à l‘augmentation de la densité de réticulation avec le concours d‘un agent réticulant, le TAIC. Pour terminer, une stratégie de modification des propriétés de surface du PVDF a été élaborée. Elle consiste dans un premier temps à radiogreffer un polymère à la surface du PVDF puis à modifier, dans un second temps, les greffons par une chimie douce et sélective. En conclusion, les approches complémentaires développées au cours de cette thèse ont permis de comprendre la radiolyse des polymères et de mettre à profit les processus élémentaires pour développer des stratégies robustes et prometteuses de modulation des propriétés. / This work deals with the modification of VDF-based polymer induced by γ-radiation as the polymer may be used in electrochemical supercapacitors. The main objective was to limit the swelling of the fluorinated matrix with a given electrolyte while a good wetting of the polymer by the liquid was also required. As the main basic process involved in polymer radiolysis is the formation of radicals, a part of the work was dedicated to the study of such species by using Electron Spin Resonance spectroscopy. A simulation model of ESR spectra was established in order to identify and quantify each radical species. The effect of several parameters such as radiation dose, annealing time or the nature of polymer matrix on the concentration of each species where investigated. A relation with the evolution of the crosslink density of the network formed during the radiolisys was proposed. In addition, one of the key steps of this work was to study the radiation crosslinking ability of VDF-based polymers and find a way to increase the crosslink density. This was achieved by incorporating, prior to the radiation process, a radiation sensitive crosslinker: TAIC. Finally, a new strategy based on the modification of surface properties of PVDF was investigated. It consists in the radiation grafting of pentafluorstyrene onto PVDF surface followed by the chemioselective functionalization of the grafted segments. As a conclusion, the different approaches used in this thesis allowed us to understand the radiolysis of VDF-based polymers and take advantage of the elementary process involved in this type of chemistry, to build up robust and promising strategies for tuning properties.

During this project it was investigated how the newly developed piezoelectric PVDF bicomponent fibre behaved when integrated in different weave constructions. The possibility to integrate conductive yarns as outer electrode was studied in order to see if it was possible to create a fully textile piezoelectric sensors. The piezoelectric properties of the bicomponent fibre is given by the sheath material, which is a polymeric material known as poly(vinylidene fluoride) (PVDF). Today only piezoelectric film made by PVDF is commercially available, but with a flexible PVDF bicomponent fibre it improves the possibility to integrate piezoelectric material into a textile construction. In this study the PVDF bicomponent fibre was integrated in the warp direction into weave constructions, such as plain weave, twill and weft rib. All the woven bands included 60 PVDF bicomponent yarns, with 24 filaments in each bundle and the average width of the bands produced was 30 mm. Different conductive materials and fibres, acting as outer electrode, were coated or integrated together with the PVDF fibre and the behaviour of the PVDF fibres was analysed. All the woven samples went through corona poling with a voltage of 7 kV in 70 ⁰C for 3 min. The weave construction that gave highest piezoelectric output signal was twill with weft that has low tex. The twill construction gave a range amplitude of 1.5- 3.3 V when subjected to a dynamic strain of about 0.25% at 4 Hz. It was shown that different conductive materials influenced the PVDF fibre in different ways, due to the resistance of the material. It was also shown that it was possible to integrate piezoelectric bicomponent fibre into a textile construction and that a fully textile piezoelectric sensor could be produced by using conductive yarns as outer electrode. / Program: Masterutbildning i textilteknik,

Les non-linéarités associées à la propagation d'une onde acoustique fort niveau se traduisent par un phénomène d'auto-démodulation d'amplitude : lorsqu'une onde porteuse ultrasonore (onde primaire) est modulée en amplitude par un signal audio, le signal audio (ondes secondaires) se reconstruit le long du lobe d'émission des ultrasons. L'antenne paramétrique ainsi obtenue présente alors une directivité très étroite en comparaison des systèmes classiques de restitution du son de dimensions comparables.<br />Ce travail de thèse vise à améliorer les systèmes existants. Pour ce faire, un outil de dimensionnement et un prototype de démonstration sont réalisés.<br />Dans un premier temps, les principes fondamentaux de l'acoustique non linéaire permettant de comprendre le phénomène d'auto-démodulation sont rappelés. Ceci permet de conclure sur l'influence du champ d'ondes primaires sur le champ d'ondes secondaires et de déterminer les propriétés nécessaires au champ d'ondes primaires pour une utilisation comme haut-parleur directif. Les distorsions induites par l'auto-démodulation sont également mises en évidence. Les prétraitements usuels de réduction des distorsions sont ensuite détaillés et évalués à l'aide d'un algorithme de simulation afin de conclure sur leurs avantages et leurs conditions d'utilisation.<br />Afin d'obtenir une directivité très étroite et un fort niveau aux fréquences ultrasonores, un réseau de transducteurs est utilisé. Nous avons choisi de travailler avec des transducteurs à base de film PVDF. Dans un second temps, une modélisation décrivant le comportement des transducteurs réalisés à l'aide de film PVDF couplé à une cavité est proposée. Celle-ci permet d'estimer la pression acoustique rayonnée par une cellule élmentaire en fonction de différents paramètres tels que les dimensions de la cavité et les propriétés du film. Enfin, l'utilisation du modèle de rayonnement d'un réseau de sources permet de définir un réseau de cellules répondant aux exigences de cette application.<br />Finalement, un prototype de haut-parleur directif est réalisé. Il est caractérisé expérimentalement en régime linéaire (sans auto-démodulation) ainsi que pour une utilisation comme haut-parleur directif afin de réaliser une validation des différentes parties de l'étude.

Die Arbeit behandelt die Entwicklung von hybrid integrierten, mikromechanischen Ultraschallwandler-Arrays auf der Basis von Polyvinylidenfluorid (PVDF). Diese breitbandigen Wandlerarrays gestatten durch eine entsprechende Dimensionierung und elektronische Ansteuerung eine gerichtete steuerbare Schallabstrahlung in Flüssigkeiten, die beispielsweise in der Strömungsmessung Verwendung finden kann. Nach theoretischen Betrachtungen zu piezoelektrischen Einzel- und Mehrelementwandlern werden der Aufbau und die Präparation der Wandlerarrays vorgestellt. Eine umfassende Charakterisierung wird anhand von akustischen und laseroptischen Messungen vorgenommen. Dabei wird besonderer Wert auf die Klärung von elektrischen und mechanischen Wechselwirkungen im Inneren der Wandler gelegt, um Erscheinungen wie Kopplungen zwischen Einzelelementen und Notwendigkeit sowie Einflüsse einer Passivierungsschicht zu erklären. Es werden Methoden und Ergebnisse der Simulation derartiger Wandlerarrays vorgestellt. Abschließend werden die Vorteile des Einsatzes solcher Arrays am Beispiel der akustischen Durchflußmessung aufgezeigt.

La technologie supercondensateur a fait l'objet d'un grand intérêt ces dernières années. Cependant, tandis qu'une grande attention a été donnée aux électrodes, aux électrolytes et aux électrolytes de polymère gélifiée, peu d'études ont été centrées sur l'amélioration des séparateurs macroporeux. Dans le cadre du projet SEPBATT/DURAMAT, les séparateurs macroporeux à base de poly(fluorure de vinylidène) (PVdF) ont été préparés par inversion de phase, pour les supercondensateurs. Nos membranes présentent également une bonne stabilité thermique, en revanche leurs propriétés mécaniques sont significativement plus faibles que celles des membranes commerciales. De plus le séparateur PVdF de porosité 80% rempli par l'électrolyte à base d'AN atteint, à 25°C, 18mS/cm, tandis que dans les mêmes conditions mais avec le séparateur commercial en cellulose, la conductivité n'atteint que 10 mS/cm. Ce travail a été complété par l'étude de techniques de renforcement (addition de composites, réticulation par l'irradiation) appliquées aux membranes précédemment préparées, pour augmenter leur tenue mécanique. Ces membranes ont montré un renforcement des propriétés mécaniques sans nuire aux propriétés de conduction ionique (15 mS/cm).

Submitted by Luiz Affonso Souza Faria (souzaffonso@gmail.com) on 2016-06-17T21:01:59Z No. of bitstreams: 1 Defesa_biblioteca_Luiz_Affonso.pdf: 3123195 bytes, checksum: 16931777d473b94f7e8908c291644f6a (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-06-21T16:45:54Z (GMT) No. of bitstreams: 1 faria_las_me_ilha.pdf: 3123195 bytes, checksum: 16931777d473b94f7e8908c291644f6a (MD5) / Made available in DSpace on 2016-06-21T16:45:54Z (GMT). No. of bitstreams: 1 faria_las_me_ilha.pdf: 3123195 bytes, checksum: 16931777d473b94f7e8908c291644f6a (MD5) Previous issue date: 2015-12-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho consiste na preparação de filmes por meio de soluções contendo poli(fluoreto de vinilideno) – PVDF dissolvido em N, N Dimetilformamida (DMF) e material cerâmico como argila montmorilonita (K10), pelo método de Fiação por Sopro em Solução (FSS). As partículas de argila foram introduzidas como um aditivo para filmes de PVDF. Os filmes obtidos foram caracterizados por Microscopia Eletrônica de Varredura (MEV), que mostrou que a introdução da argila ao PDVF não afetou a sua morfologia, as mesmas se apresentaram aleatoriamente dispersas, homogêneas, e sem uma direção preferencial. Os resultados obtidos por Difratometria de Raio – X (DRX) mostrou pico mais intenso em 2θ = 20,8o característico da fase β polar e um ombro em 2θ = 18,8o característico da fase cristalina α do PVDF, porém para argila K10 apresenta um pico em 2θ = 8,9o correspondendo a um espaçamento basal de 9,9 Ǻ e outros picos correspondentes ao mineral muscovita e também referente ao quartzo. Análises termogravimétricas (TGA) revelaram que o PVDF possui um comportamento estável até próximo de 420°C, para argila a perda ocorre abaixo de 120°C devido às moléculas de água e também a desidroxilação argilomineral. A determinação do pHPCZ é o ponto onde a curva experimental de pHfinal x pHinicial encontra a reta correspondente ao pHfinal = pHinicial, assim o ponto obtido foi de 6,57, pois neste ponto a carga da superfície do material é zero. A Espectrometria de Absorção Atômica de Alta Resolução com fonte contínua (HR – CS AAS - do inglês: High - resolution Continuum Source Atomic Absorption Spectrometry) foi utilizada para determinar a concentração dos íons metálicos de Pb e Cu nos estudos de adsorção. As concentrações das soluções em contato com o material PVDF/Argila k10 foram medidas para a determinação da capacidade de adsorção através de isotermas com diferentes concentrações molares dos íons metálicos. No estudo de adsorção de Pb e Cu, ambos apresentaram capacidade máxima de adsorção pelo adsorvente (Nfmáx) foram satisfatórios, no qual os valores Nfmáx (teórico) estiveram próximos do Nf (experimental) de 0,1804 x 10-5 para o Cu e de 0,2416 x 10-5 para o Pb e que o tempo necessário para que o equilíbrio fosse atingido é de 10h. O estudo cinético revelou que os dados experimentais no meio aquoso e seus respectivos íons metálicos podem ser descrito pelo modelo pseudo - segunda - ordem com um coeficiente de determinação (R²) de 0,9992 para o Pb e 0,9994 para o Cu. / This work is the preparation of films by means of solutions containing poly (vinylidene fluoride) - PVDF dissolved in N, N-dimethyl formamide (DMF) and ceramic material such as montmorillonite clay (K10), the wiring method Blow solution (FSS). The clay particles were introduced as an additive to PVDF films. The films were characterized by scanning electron microscopy (MEV), which showed that the introduction of the clay PDVF did not affect their morphology, they performed randomly dispersed, homogeneous, and without a preferred direction. The results obtained by diffraction of ray - X (XRD) showed the most intense peak at 2θ = 20,8o characteristic of β-polar phase and one shoulder at 2θ = 18,8o characteristic of the α crystal phase of PVDF, but to present a K10 clay peak at 2θ = 8,9o corresponding to a basal spacing of 9.9 Ǻ and other peaks corresponding to the mineral muscovite and also related to quartz. Thermogravimetric Analysis (TGA) revealed that the PVDF has a stable performance up to near 420°C to clay loss occurs below 120°C due to water molecules and also clay mineral dehydroxylation. The determination of pHPCZ is the point where the experimental curve pHend x pHearly finds the line corresponding to the pHend = pHearly therefore the point obtained was 6.57 because at this point the material surface charge is zero. The High - resolution Continuum Source Atomic Absorption Spectrometry (HR - CS ASS) it was used to determine the concentration of metallic Pb and Cu ion in the adsorption studies. The concentrations of the solutions in contact with the PVDF/K10 clay material were measured to determine the adsorption capacity through isotherms with different molar concentrations of metal ions. In the study of Pb and Cu adsorption, both showed adsorption capacity of the adsorbent (Nf máx) were satisfactory in which values Nf máx (theoretical) were close to Nf (experimental) from 0.1804 x 10-5 to Cu and from 0.2416 x 10-5 to Pb and the time required for equilibrium to be reached is 10h. The kinetic study showed that the experimental data in the aqueous medium and the respective metal ions can be described by the model pseudo - second - order with a coefficient of determination (R²) from 0.9992 for Pb and 0.9994 for Cu.

Orientador: Mirian Cristina dos Santos / Resumo: Este trabalho consiste na preparação de filmes por meio de soluções contendo poli(fluoreto de vinilideno) – PVDF dissolvido em N, N Dimetilformamida (DMF) e material cerâmico como argila montmorilonita (K10), pelo método de Fiação por Sopro em Solução (FSS). As partículas de argila foram introduzidas como um aditivo para filmes de PVDF. Os filmes obtidos foram caracterizados por Microscopia Eletrônica de Varredura (MEV), que mostrou que a introdução da argila ao PDVF não afetou a sua morfologia, as mesmas se apresentaram aleatoriamente dispersas, homogêneas, e sem uma direção preferencial. Os resultados obtidos por Difratometria de Raio – X (DRX) mostrou pico mais intenso em 2θ = 20,8o característico da fase β polar e um ombro em 2θ = 18,8o característico da fase cristalina α do PVDF, porém para argila K10 apresenta um pico em 2θ = 8,9o correspondendo a um espaçamento basal de 9,9 Ǻ e outros picos correspondentes ao mineral muscovita e também referente ao quartzo. Análises termogravimétricas (TGA) revelaram que o PVDF possui um comportamento estável até próximo de 420°C, para argila a perda ocorre abaixo de 120°C devido às moléculas de água e também a desidroxilação argilomineral. A determinação do pHPCZ é o ponto onde a curva experimental de pHfinal x pHinicial encontra a reta correspondente ao pHfinal = pHinicial, assim o ponto obtido foi de 6,57, pois neste ponto a carga da superfície do material é zero. A Espectrometria de Absorção Atômica de Alta Resolução com fonte con... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work is the preparation of films by means of solutions containing poly (vinylidene fluoride) - PVDF dissolved in N, N-dimethyl formamide (DMF) and ceramic material such as montmorillonite clay (K10), the wiring method Blow solution (FSS). The clay particles were introduced as an additive to PVDF films. The films were characterized by scanning electron microscopy (MEV), which showed that the introduction of the clay PDVF did not affect their morphology, they performed randomly dispersed, homogeneous, and without a preferred direction. The results obtained by diffraction of ray - X (XRD) showed the most intense peak at 2θ = 20,8o characteristic of β-polar phase and one shoulder at 2θ = 18,8o characteristic of the α crystal phase of PVDF, but to present a K10 clay peak at 2θ = 8,9o corresponding to a basal spacing of 9.9 Ǻ and other peaks corresponding to the mineral muscovite and also related to quartz. Thermogravimetric Analysis (TGA) revealed that the PVDF has a stable performance up to near 420°C to clay loss occurs below 120°C due to water molecules and also clay mineral dehydroxylation. The determination of pHPCZ is the point where the experimental curve pHend x pHearly finds the line corresponding to the pHend = pHearly therefore the point obtained was 6.57 because at this point the material surface charge is zero. The High - resolution Continuum Source Atomic Absorption Spectrometry (HR - CS ASS) it was used to determine the concentration of metallic Pb and Cu ion i... (Complete abstract click electronic access below) / Mestre

Poly(vinylidene) fluoride (PVDF) nano-composite membranes were prepared. The dope solution contained varied concentrations of superhydrophobic SiO2 nano-particles. The fabricated flat sheet membranes were characterized extensively by SEM, FTIR, water contact angle, LEPw, surface roughness, pore size diameter and pore size distribution. The effect of the nano-particles on the membrane performance was then analysed. The nano-composite membranes showed increased surface pore diameter, elevated water contact angle measurements with lower LEPw when compared to the neat membrane. The 7 wt. % nano-composite membrane showed the greatest flux in a VMD process with 2.9 kg/m2.h flux achieved accounting to a 4 fold increase when compared to the neat membrane. Desalination test were carried out using a 35 g/L synthetic salt water and rejection >99.98% was obtained. The best performing nano-composite dope solution (7 wt. %) was then further treated for performance enhancement by increasing the water content to increase pore size and pore size distribution followed by coating with nano-fibres. The uncoated and coated flat sheets, were characterized by SEM, surface roughness, LEPw and CAw. Flux analysis showed that the increase in water content had little effects on the VMD flux. It also suggests that; the nano-fibre layer posed very little resistance to mass transfer. A comparison of VMD and DCMD was also done experimentally.