In this project, we have designed and synthesized a new series of long-chain, water-soluble, dendritic, anionic amphiphiles [3CAmn, RCONHC(CH₂CH₂COOH)₃, R= CnH2n+1] to alleviate the low aqueous solubility of fatty acids. The dendritictricarboxlyato headgroup improves aqueous solubility and allows us to measure the intrinsic biological activity of our amphiphiles without the potential hindrance of low aqueous solubility. The aqueous solubilities of the anionic amphiphiles have been measured and were vastly higher than that of fatty acids. For example, 3CAm17 (1700 μM at pH 7.2) has much better aqueous solubility than the C₁₈ fatty acid analog (<<1 micromol at pH 7.4). Following the determination of aqueous solubility, both anionic and nonionic amphiphiles were tested against a wide variety of microorganisms. The anionic amphiphiles were mostly active against Candida albicans (4.4 microgram/mL), Saccharomyces cerevisiae (4.4 μg/mL), and Mycobacterium smegmatis (18 microgram/mL) and exhibited modest activity against both Gram-negative (71–280 microgram/mL) and Gram-positive bacteria (36– >6300 microgram/mL). With the exception of Neisseria gonorrhoeae (9.8 microgram/mL), the nonionic amphiphiles were mostly minimally active or inactive against Gram-negative bacteria (630–5000 microgram/mL). The nonionic amphiphiles were similarly inactive against fungi (625–5000 microgram/mL). However, the nonionic amphiphiles exhibited good activity against M. smegmatis (20 microgram/mL) and exhibited the best activity against Grampositive bacteria, such as MRSA (22 microgram/mL), Staphylococcus aureus (20 microgram/mL), and Micrococcus luteus (20 microgram/mL). The anionic and nonionic amphiphiles were also tested for possible spermicidal and anti-human immunodefiency virus (HIV) activity. The anionic amphiphiles exhibited anti-HIV activity (EC₅₀, 73–340 microgram/mL), but lacked spermicidal activity. The series had comparable anti-HIV activity to the commercial product N-9 (80 microgram/mL). Except 3CAm13, all anionic amphiphiles (1.4–4) had better selectivity indices than that of N-9 (0.9). The nonionic amphiphiles exhibited both anti-HIV (44–67 microgram/mL) and spermicidal activity (226–2000 microgram/mL). The nonionic amphiphile were more spermicidal and antiviral than Nonoxynol-9. In addition to biological activity, we determined whether the anionic amphiphiles could be utilized as corrosion inhibitors or ore flotation enhancers. The anionic amphiphiles formed stable thin films on silver oxide that were resistant to ethanol washings. We also measured the water contact angles of the anionic amphiphiles on mineral surfaces [apatite (95°), calcite (92°)]. / Ph. D.

Many previous studies of biological activity in a homologous series of amphiphiles have shown a cut-off effect, where the biological activity increases with an increase in chain length, after which the activity plateaus or weakens. One factor suspected to cause this problem is solubility issues. We have designed several series of very hydrophobic, water-soluble amphiphiles to overcome this problem. Three homologous series containing mobile hydrophobic moieties and two series of epimers containing rigid cholestane moieties have been synthesized; the hydrophobic moiety is connected to the first-generation, Newkome-type dendron via a ureido linker. We have demonstrated that as tris(triethanolammonium) salts, these amphiphiles show excellent solubility in water. The solubilities in aqueous triethanolamine solution of the three series containing mobile hydrophobic moieties are 19,500 to 25,700 μM depending on the formula weight of the homolog, while those containing rigid cholestane moieties are 18,900 and 17,400 μM. Having eliminated the solubility issue, the antimicrobial activity against a broad spectrum of microorganisms has been screened. We have demonstrated that the antimicrobial activity depends on the amphiphile-series, species, chain-length, or epimer specificities, as well as hydrophobicity. The one-tailed, tri-carboxylato amphiphiles are generally better than the other series, with two exceptions. First, the two-tailed tri-carboxylato amphiphiles, <b>3CUr1(11)₂</b> and <b>3CUr1(12)₂</b>, are more active against <i>Cryptococcus neoformans</i>; in fact, both amphiphiles (MICs are 6.9 and 7.2 μM, respectively) are considered to display good antifungal activity. Second, amphiphile <b>3CUr-β-cholestane</b>, whose MIC is 27 μM, is more active against <i>Staphylococcus aureus</i>. Overall, these new tri-carboxylato amphiphiles only exhibit moderate activity with two promising leads. Furthermore, we have demonstrated the intrinsic activity (MIC₀) of the one-tailed, tri-carboxylato amphiphile series (<b>3CUrn</b>) against <i>Mycobacterium smegmatis</i>. All the MIC₀s observed are at least 8-fold lower than the corresponding CMCs. Amphiphile <b>3CUr16</b> is the most active; the MIC₀ is 100-fold smaller than the CMC. With this consideration, we have suggested that the mechanism of action of the antimycobacterial activity in amphiphile <b>3CUr16</b> is not related to detergency. / Ph. D.

In this project, we synthesized a new homologous series of five long-chain, two-headed amphiphiles [2CAm13, 2CAm15, 2CAm17, 2CAm19, 2CAm21; CH3(CH2)n-1CONHC(CH3)(CH2CH2COOH)2, n = 13, 15, 17, 19, 21]. The synthesis of the 2CAmn series was accomplished in four steps. The first step involves a reaction of nitroethane and two equivalents of tert-butyl acrylate to create the nitrodiester synthon [O2NC(CH3)(CH2CH2COOtBu)2] by successive Michael additions. The second step in the synthesis consists of a reduction of nitrodiester with H2 and Raney nickel to give the diesteramine [H2NC(CH3)(CH2CH2COOtBu)2]. The third step is the condensation of an acid chloride with diesteramine to give an alkanamido diester [2EAmn; CH3(CH2)n-1CONHC(CH3)(CH2CH2COOtBu)2, n = 13, 15, 17, 19, 21]. The final step is the removal of the tert-butyl protecting groups to give 2CAmn. Critical micelle concentration measurements were collected by the pendant drop method for measuring surface tension for a series of triethanolamine/2CAmn solutions to establish the concentration required for detergency. The CMCs for the 2CAmn series were found to decrease in value from 3.0 Ã 10â 2 M (2CAm13) to 1.7 Ã 10â 4 M (2CAm21) in a linear fashion [log CMC = (â 0.28 ± 0.01)n + (2.2 ± 0.1)]. The CMCs for the 2CAmn series falls in between the CMCs for three series of homologues three-headed amphiphiles (3CAmn, 3CCbn, 3CUrn) and the CMCs for fatty acids, with fatty acids having the lowest CMCs. Antibacterial activity (minimal inhibitory concentrations, MICs) for a series of homologous dendritic two-headed amphiphiles and three series of homologous, three-headed amphiphiles against Staphylococcus aureus and methicillin-resistent S. aureus (MRSA) were measured by broth microdilution to compare the effect of chain length and, hence, hydrophobicity. Inoculum density affected antibacterial activity of the 2CAmn series against both S. aureus and MRSA. MIC measurements at different cell densities showed that activity decreased with higher cell densities. For all four series, the MICs were relatively flat at low inoculum densities. This flat region defines the intrinsic activity, MIC0. The MIC0 results revealed that inoculum density, chain-length, and hydrophobicity all influenced antibacterial activity and that activity correlates strongly with clogp, an established measure of hydrophobicity. The most hydrophobic members from each homologous series exhibited antibacterial activity. The most active homologue of the 2CAmn series was 2CAm21 with MIC0 of 2.0 ± 1.0 and 3.2 ± 1.0 μM against S. aureus and MRSA, respectively. The CMCs and MIC0s of the two- and three-headed amphiphiles were compared for both S. aureus and MRSA to gauge the effect that micelles may have on activity. Amphiphile 2CAm19 has the largest ratio between CMC and MIC0 (CMC/MIC0 = 205) against S. aureus and 3CUr20 has the largest ratio (CMC/MIC0 = 339) against MRSA. These ratios suggest that micelle formation is not a mechanism of action for anti-Staphylococcal activity. / Master of Science

This project is about the synthesis of homologous series of two-headed, long-chain amphiphiles (the 2CCbn series, where n = 16, 18, 20, 22, 30, 5α-cholestan-3Ã -ol). The 2CCbn series was synthesized in five steps. The first step involves a reaction of nitroethane and two equivalents of tert-butyl acrylate to form nitrodiester by successive Michael addition reaction. The second step is the reduction of nitrodiester with Raney nickel to form aminodiester. The third step involves a reaction of aminodiester with di-tert-butyl dicarbonate [(Boc)2O] to form isocyanatediester. The fourth step is addition of iscocyanatediester with aliphatic alcohol to give alkyl carbamate diester (2ECbn) series. The fifth step is the removal of the tert-butyl protecting group to give the 2CCbn series. The critical micelle concentrations (CMC) were measured by the pyrene-based fluorescent probe method. The pyrene excited at 345 nm and fluoresces with maxima at 374 nm (I1) and 385 nm (I3). The stock solution and the dilution series for each amphiphiles were made in 0.9% triethanolamine solution. The CMCs were measured at two pH ~9.2 and 7.4. The CMCs were determined by plotting I1/I3 vs. concentrations. The CMCs were decreasing with increasing chain length. The CMCs for the 2CCbn series are lower than the 3CCbn series but higher than the fatty acids. The minimal inhibitory concentrations were measured against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. These strains were grown on BHIB+S with 5% triethanolamine. The MICs of the 2CCbn series amphiphiles were measured by using microtiter plate reader and by looking turbidity. The cutoff effect was found for the 2CCbn series. The MIC decreased up to C20 chain length and started rising for C22. The 2CCb18 (MICâ 2.2 µg/mL) of the 2CCbn series was the most effective amphiphile against S. aureus and MRSA. The CMC/MIC ratio was used to determine the safety of an amphiphile as a drug use. The amphiphile 2CCb18 has given the largest safety ratio (CMC/MIC = 273) against S. aureus and MRSA. It suggests that micelle formation is not a mechanism of action for anti-Staphylococcal activity. / Master of Science

Nous démontrons qu'il est possible de former des bicouches fluides non phospholipides en milieu aqueux avec un mélange d'acide palmitique (PA), cholestérol (Chol) et sulfate de cholestérol (Schol) avec une proportion molaire de 30/28/42. Ces liposomes non phospholipidiques peuvent maintenir un gradient de pH (pHinterne 8 / pHexterne 6) sur une période 100 fois plus longue que les liposomes faits de 1-palmitoyl-2-oléoyl-sn-glycéro-3-phosphocholine (POPC) et de cholestérol (60/40 mol/mol). De plus, ces LUV non phospholipidiques protègent l'acide ascorbique d'un milieu oxydant (1 mM de fer (III)). Une fois piégé dans les liposomes, l'acide ascorbique présente une vitesse de dégradation similaire à celle obtenue en l'absence de fer(III). Ces performances illustrent la perméabilité exceptionnellement limitée de ces liposomes, ce qui implique qu'ils peuvent présenter des avantages comme nanocontenants pour certaines applications. D'autre part, des vésicules unilamellaires géantes (GUV pour Giant Unilamellar Vesicles) ont été formées à partir d'un mélange d'acide palmitique et de cholestérol (30/70 mol/mol). Ces GUV sont stables sur l'échelle de temps de semaines, elles ne s'agrègent pas et elles sont sensibles au pH. Afin d'établir la formation des GUV, l'imagerie par microscopie confocale à balayage laser a été utilisée. Deux sondes fluorescentes ont été utilisées: le rouge du Nile, une sonde hydrophobe qui s'insère dans le cœur hydrophobe des bicouches lipidiques, et la calcéine, une sonde hydrophile qui a été emprisonné dans le réservoir interne des GUV. Cette approche a permis l'observation des parois des GUV ainsi que de leur contenu. Ces résultats montrent la possibilité de former de nouveaux microcontenants à partir d'un mélange d'un amphiphile monoalkylé et de stérol. / First, we demonstrate that it is possible to form non-phospholipid fluid bilayers in aqueous milieu with a mixture of palmitic acid (PA), cholesterol (Chol), and cholesterol sulfate (Schol) in a molar proportion of 30/28/42. These non-phospholipid liposomes can sustain a pH gradient (pHinternal 8 / pHexternal 6) 100 times longer than LUVs made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol (60/40 mol/mol). These non-phospholipid LUVs are shown to protect ascorbic acid from an oxidizing environment (1 mM Iron (III)). Once entrapped in these liposomes, ascorbic acid displays a degradation rate similar to that obtained in the absence of Iron (III). This ability illustrates the exceptionally limited permeability of these liposomes, indicating that they can present advantages as nanocontainers for some applications. Second, Giant Unilamellar Vesicles (GUVs) were formed from a mixture of palmitic acid and cholesterol (30/70 mol/mol). These GUVs were stable over weeks, did not aggregate, and were pH-sensitive. In order to establish their formation, confocal laser scanning microscopy imaging was carried out. Two fluorescent probes were used: Nile Red, a hydrophobic probe that inserted in the hydrophobic core of lipid bilayers, and calcein, a hydrophilic probe that was trapped in the GUV internal pool. This approach allowed observation of both the walls of the GUVs as well as their entrapped content. These results show the possibility to form novel microcontainers from a mixture of a monoalkylated amphiphile and sterols.

Le défi majeur de la thérapie génique à base de siARN est sa délivrance sûre et efficace. Récemment, notre groupe a mis au point des dendrimères amphiphiles comme vecteurs robustes et efficaces de délivrance non-virale de siARN, qui combinent les avantages de délivrance des vecteurs lipidiques et polymèriques. J’ai effectué au cours de ma thèse de doctorat une analyse de la relation structure/activité (SAR) d'une série de dendrimères comportant des queues hydrophobes de différentes longueurs. Nos résultats démontrent qu’un équilibre optimal entre la longueur de la chaîne alkyle hydrophobe et la partie hydrophile dendritique joue un rôle crucial sur leur capacité d’auto-assemblage, ainsi que sur leur activité de transport des siRNA. En outre, en combinant bola-amphiphiles et nos dendrimères amphiphiles, nous avons développé un nouveau dendrimère bola-amphiphile dont nous avons étudié les propriétés d’auto-assemblage et l'efficacité de transport du siARN correspondant. Ce dendrimère bola-amphiphile particulier a été en mesure de réagir à des espèces réactives de l'oxygène pour la délivrance spécifique, ouvrant ainsi de nouvelles perspectives pour la conception de vecteurs stimuli-déclencheurs pour siARN ciblés. Enfin, nous avons étudié l’«effet d'éponge à protons» des vecteurs dendritiques amphiphiles à l'aide de la technique du film Langmuir en monocouche. Nos résultats ont prouvé le gonflement des vecteurs dendritiques amphiphiles par protonation, offrant ainsi des données expérimentales permettant de soutenir sans ambiguïté l’hypothèse de l'«effet d'éponge à protons». / A key challenge in RNAi-based gene therapy is the safe and effective siRNA delivery. Recently, our group has established amphiphilic dendrimers as robust and effective nonviral delivery vectors for siRNA, which combine the beneficial delivery features of both lipid and dendritic polymer vectors while overcoming their shortcomings.With the desire to understand the underlying mechanism of amphiphilic dendrimers for efficient delivery, I performed a structure/activity relationship (SAR) analysis of a series of dendrimers featuring hydrophobic tails of different lengths during my PhD thesis. We systematically investigated these dendrimers for their self-assembling characters and their capacities for both binding and delivery of siRNA. Our results demonstrate that an optimal balance between the hydrophobic alkyl chain length and the hydrophilic dendritic portion plays a crucial role in the self-assembly and the delivery activity towards siRNA.Furthermore, we developed a novel bola-amphiphilic dendrimer by combining bola-amphiphiles and our amphiphilic dendrimers and studied their self-assembly properties and the corresponding siRNA delivery efficiency. This peculiar bola-amphiphilic vector was able to respond to reactive oxygen species for specific delivery, opening a new perspective for the design of stimuli-trigged vectors for targeted siRNA delivery.Finally, I studied the “proton sponge effect” of the amphiphilic dendrimer vectors using the Langmuir monolayer film technique. Our results gave direct evidence of swelling of the amphiphilic dendrimers upon protonation, offering unambiguous experimental data to support the “proton sponge effect”.

Nous démontrons qu'il est possible de former des bicouches fluides non phospholipides en milieu aqueux avec un mélange d'acide palmitique (PA), cholestérol (Chol) et sulfate de cholestérol (Schol) avec une proportion molaire de 30/28/42. Ces liposomes non phospholipidiques peuvent maintenir un gradient de pH (pHinterne 8 / pHexterne 6) sur une période 100 fois plus longue que les liposomes faits de 1-palmitoyl-2-oléoyl-sn-glycéro-3-phosphocholine (POPC) et de cholestérol (60/40 mol/mol). De plus, ces LUV non phospholipidiques protègent l'acide ascorbique d'un milieu oxydant (1 mM de fer (III)). Une fois piégé dans les liposomes, l'acide ascorbique présente une vitesse de dégradation similaire à celle obtenue en l'absence de fer(III). Ces performances illustrent la perméabilité exceptionnellement limitée de ces liposomes, ce qui implique qu'ils peuvent présenter des avantages comme nanocontenants pour certaines applications. D'autre part, des vésicules unilamellaires géantes (GUV pour Giant Unilamellar Vesicles) ont été formées à partir d'un mélange d'acide palmitique et de cholestérol (30/70 mol/mol). Ces GUV sont stables sur l'échelle de temps de semaines, elles ne s'agrègent pas et elles sont sensibles au pH. Afin d'établir la formation des GUV, l'imagerie par microscopie confocale à balayage laser a été utilisée. Deux sondes fluorescentes ont été utilisées: le rouge du Nile, une sonde hydrophobe qui s'insère dans le cœur hydrophobe des bicouches lipidiques, et la calcéine, une sonde hydrophile qui a été emprisonné dans le réservoir interne des GUV. Cette approche a permis l'observation des parois des GUV ainsi que de leur contenu. Ces résultats montrent la possibilité de former de nouveaux microcontenants à partir d'un mélange d'un amphiphile monoalkylé et de stérol. / First, we demonstrate that it is possible to form non-phospholipid fluid bilayers in aqueous milieu with a mixture of palmitic acid (PA), cholesterol (Chol), and cholesterol sulfate (Schol) in a molar proportion of 30/28/42. These non-phospholipid liposomes can sustain a pH gradient (pHinternal 8 / pHexternal 6) 100 times longer than LUVs made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol (60/40 mol/mol). These non-phospholipid LUVs are shown to protect ascorbic acid from an oxidizing environment (1 mM Iron (III)). Once entrapped in these liposomes, ascorbic acid displays a degradation rate similar to that obtained in the absence of Iron (III). This ability illustrates the exceptionally limited permeability of these liposomes, indicating that they can present advantages as nanocontainers for some applications. Second, Giant Unilamellar Vesicles (GUVs) were formed from a mixture of palmitic acid and cholesterol (30/70 mol/mol). These GUVs were stable over weeks, did not aggregate, and were pH-sensitive. In order to establish their formation, confocal laser scanning microscopy imaging was carried out. Two fluorescent probes were used: Nile Red, a hydrophobic probe that inserted in the hydrophobic core of lipid bilayers, and calcein, a hydrophilic probe that was trapped in the GUV internal pool. This approach allowed observation of both the walls of the GUVs as well as their entrapped content. These results show the possibility to form novel microcontainers from a mixture of a monoalkylated amphiphile and sterols.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Les poly (3-hydroxyalcanoates) (PHAs) sont des polyesters aliphatiques produits et accumulés par des bactéries en tant que réserve de carbone et d'énergie. Ils sont constitués d'unités β-hydroxyesters et possèdent des chaînes latérales de longueur variable, pouvant être fonctionnalisées. Ils possèdent des propriétés de biodégradabilité et de biocompatibilité; ceci leur confère de vastes possibilités d'utilisation dans le domaine biomédical, notamment pour la mise au point de systèmes de libération contrôlée de principes actifs. Dans cette optique, nous nous sommes intéressés à la synthèse de copolymères amphiphiles de différentes architectures à base de PHAs, ainsi qu'à l'étude de leurs propriétés d'auto-association en milieu aqueux. Une méthode simple et efficace permettant le greffage d'oligomères de poly (éthylène glycol) (PEG) a tout d'abord été mise au point grâce à l'utilisation de la chimie « click ». Une série de copolymères diblocs bien définis PHA-b-PEG a ainsi pu être synthétisée par cycloaddition de Huisgen catalysée par le cuivre (CuAAC). Les copolymères diblocs à base de PHAs à moyennes chaînes latérales (PHA-mcl) ont montré leur capacité à s'auto-associer en milieu aqueux et à former des micelles monodisperses présentant une concentration micellaire critique très faible. Par la suite des copolymères de type greffés PHOU-g-PEG ont été synthétisés par addition thiol-ène. Les analyses par cryo microscopie électronique à transmission (cryo-TEM) ont montré que dans ce cas les copolymères s'auto-associaient en structures vésiculaires, ou polymersomes. Enfin, la synthèse de copolymères amphiphiles greffés porteurs de chaînes perfluorées PHOU-g-(F;PEG) a permis l'obtention de structures auto-associées plus complexes. Le cryo-TEM a en effet révélé la formation de micelles multicompartimentées, c'est à dire possédant un coeur présentant une séparation de phase entre les domaines hydrophobes et les domaines fluorés. Des tests biologiques préliminaires ont montré la cytocompatibilité de ces micelles / Poly (3-hydroxyalkanoates) are natural aliphatic polyesters produced and accumulated by many bacteria as carbon and energy supply. They consist of β-hydroxy ester units, with pendant side chains of different lengths that can be functionalized. Thanks to their biodegradability and biocompatibility, they are promising polymers for biomedical applications, especially for controlled drug delivery systems. In this context, we aimed to synthesize PHA-based amphiphilic copolymers with different molecular architectures, and to study their self-assembly in water. First, a simple and straightforward method using click chemistry has been used to graft poly(ethylene glycol) (PEG) oligomers. A series of well-defined diblock copolymers PHA-b-PEG has thus been synthesized using copper-catalyzed azide-alkyne cycloaddition (CuAAC). Medium chain length PHA-based diblock copolymers have shown their ability to self-assemble into stable micelles having very low critical micelle concentrations. Afterwards, amphiphilic graft copolymers PHOU-g-PEG have been synthesized using thiol-ene addition. In this case, cryo-electron microscopy (cryo-TEM) analysis revealed that graft copolymers self-assembled into vesicular morphologies, i.e. in polymersomes. Finally, the synthesis of amphiphilic graft copolymers bearing perfluorinated chains PHOU-g-(F;PEG) was performed. After aqueous self-assembly, cryo-TEM shown the formation of multicompartment micelles, i.e. with a core displaying segregated hydrophobic and fluorophilic domains. Moreover, these multicompartment micelles have shown their cytocompatibility

De nouvelles membranes synthétiques poreuses à morphologies et performances contrôlées ont été développées grâce à l'utilisation de copolymères à blocs. De telles macromolécules peuvent s'auto-organiser en structures de géométries bien définies et sont par ailleurs capables d'agir sur la courbure des interfaces. De nouveaux copolymères triblocs ABA, possédant un bloc central en poly(oxyéthylène) et deux blocs terminaux en poly(styrène), ont été préparés en utilisant une stratégie de synthèse originale fondée sur la combinaison de réactions de modification chimique des bouts de chaîne et d'une méthode de polymérisation radicalaire contrôlée par les nitroxydes. Les diverses morphologies formées par auto-assemblage de ces copolymères à blocs dans des films fins ont par la suite été étudiées en fonction de leur structure et de plusieurs paramètres opératoires (vitesse d'évaporation, concentration, ...etc). A partir de ces résultats, de nouvelles membranes modèles possédant des pores cylindriques organisés de dimension nanométrique calibrée et contrôlée ont été élaborées. De plus, la synthèse d'autres copolymères triblocs amphiphiles a été développée en adoptant une démarche multi-étapes intégrant une polycondensation. Ces copolymères sont constitués en leur centre d'un bloc hydrophobe en poly(éther imide) aromatique et pour leurs extrémités de blocs hydrophiles en poly(oxyéthylène). Des membranes à propriétés d'usage définies ont ensuite été conçues en maîtrisant leurs mécanismes de structuration, soit au moyen des paramètres du procédé, soit en introduisant des copolymères triblocs dans la formulation. Ces derniers ont été utilisés comme additifs afin de mettre à profit leurs propriétés d'auto-organisation interfaciale dans une solution de poly(éther imide) où se produit une séparation de phase induite par un non-solvant. Finalement, les performances de l'ensemble des membranes obtenues dans ce travail ont permis de valider les deux approches envisagées.