Novel amphiphilic graft copolymers with a backbone of poly(norbornene) (PNB) with poly(ethylene oxide) (PEO) grafts have been synthesised by a combination of ring opening metathesis and anionic polymerisation methods. The polymer has been prepared with hydrogenous and deuterated grafts and with grafts of different degrees of polymerisation. These graft copolymers spread at the air-water and air-PEO solution interface forming thin films and their organisation and dynamic behaviour is discussed. Monolayer behaviour was characterised from surface pressure isotherms and it was demonstrated that the shape of the isotherm is dependent on graft length and on the concentration of PEO in the subphase. Using neutron reflectometry the organisation of such spread films at the air-water interface have been obtained over a range of surface concentrations for each length of PEO graft. Data were analysed by both exact calculation methods and the partial kinematic approximation and the models adopted were verified by applying the model independent Bayesian analysis. All yield the same description i.e. the hydrophobic backbone remains at the uppermost surface while the PEO grafts penetrate the subphase. The PEO layer increases in thickness with increased surface concentration and graft length. In each case the rate of increase with surface concentration was initially rapid but above a critical concentration, a slower rate was observed. In this latter regime the variation of the tethered layer height scales with surface density (ơ) and degree of polymerisation of the graft (N) as, r(_s) = N(^1.06)ơ(^0.33),which agrees well with scaling and self consistent field theory of polymer brushes. The dynamic behaviour of each copolymer film spread on water has been studied using surface quasi-elastic light scattering. A resonance between the capillary and dilational waves is observed at identical surface concentrations for each copolymer film. The viscoelastic behaviour of the dilational mode is reminiscent of Kramers-Kronig relations. The phenomenon of resistive mode mixing was observed in frequency dependency studies.

A series of sulfonate anionic lipids esters derived from 4-sulfobenzoic acid (single chain) or 5-sulfoisophthalic acid (double chain) with chain length from C14 to C18 were synthesized and characterized. The sodium salts were uniformly insoluble in ethanol; the tetramethylammonium salts of the single chain derivative from oleyl alcohol and the double chain derivative from 2-octyldodecan-1-ol were sufficiently soluble for subsequent experiments. Lipids in ethanol and aqueous buffers were mixed in a microfluidic system (NanoAssmblr ® microfluidic mixer) to prepare a lipid dispersion containing vesicles and/or nanoparticles. Initial studies on prediction and controlling vesicle size based on lipid geometric parameters showed that particle size could be successfully affected and controlled by altering lipid compositions consistent with the formation of vesicles. A survey using high resolution cryo-Scanning Transmission Electron microscopy of the sample made by the microfluidic mixer demonstrated that vesicles were formed but a majority of the sample reformed to other aggregates, which complicated the interpretation of the initial product distribution. Further investigation on the efficiency of incorporation of phospholipids into vesicles indicated that 55% of the initial phospholipid appeared in the vesicle fractions. Sulfonate anionic lipids are incorporated into vesicles with lower efficiency and reach a threshold beyond which the sulfonate lipid is not incorporated. Entrapment efficiency was studied with three dyes. Different concentrations of the hydrophobic neutral dye Nile red, the hydrophilic cationic dye neutral red and the hydrophilic anionic dye hydroxypyrene trisulfonate (HPTS) were prepared. The entrapment efficiency was quantitatively analyzed by HPLC, and electrospray mass spectrometry; up to 15% of the initial dye present could be entrapped. Vesicles permeability assays using the ion channel gramicidin and the ion carrier valinomycin with HPTS-loaded vesicle samples showed that vesicle samples made by the microfluidic mixer and made by a conventional extrusion method appeared to behave in the same manner. Addition of a sulfonate anionic lipid to the lipid mixture resulted in vesicle leakage. The unilamellar proportion of HPTS loaded vesicle samples was assessed using a mellitin assay. A vesicle sample made by the microfluidic mixer was 80% unilamellar; a vesicle sample made by the extrusion method on the same lipid mixture was 60% unilamellar. / Graduate / mengxiuzheng@gmail.com

No description available.

The project contributes to the general theme of complex chemical systems and strengthens ties with Innospec, a multi-national chemical company. Sodium lauroyl methyl isethionate (SLMI. Trade name “Iselux”) is a newly developed surfactant with attractive product properties for personal care applications. Little is known about the fundamental surface and solution properties of SLMI, and it is not currently possible to use information on available surfactants to predict phase behaviour. We characterise the solution and liquid crystalline phase behaviour of the SLMI/water system using a combination of optical microscopy, X-ray scattering and differential scanning calorimetry techniques. SLMI is synthesised using a batch process that leads to variable component concentrations. Preliminary studies conducted by Innospec indicate that the presence of particular process components has a significant influence on SLMI formulation rheological properties. We investigate the effects of synthesis-derived components on the rheological properties of the SLMI/sodium {(3-(dodecanoylamino)propyl)(dimethyl)ammonio)}acetate/water system using rheology and light scattering (static and dynamic) techniques. SLMI is often formulated into personal care products on mixing aqueous formulation components. Micelle growth occurs via a mechanistic process that is not understood and the equilibrium viscosity is attained at a time after mixing that ranges from seconds to weeks. Developing an improved understanding of the micelle growth mechanism is of both academic and industrial value. We utilise static light scattering and nuclear magnetic resonance techniques to probe a range of samples in the viscoelastic region of the SLMI/(carboxymethyl)hexadecyldimethyl ammonium hydroxide/water system. Experimental findings improve our current understanding of micelle growth process and provide a platform for future research on non-equilibrium mixing kinetics. In the final section we investigate salt-induced cloud point and precipitation phenomena in the SLMI/salt/water system. The cloud point is commonly observed in surfactant and protein systems by increasing the solution temperature above a critical value, resulting in phase separation of solute-rich and solute-depleted layers. Cloud point induced phase separation may also be prompted by addition of salt. The mechanistic process driving electrolyte-induced cloud point phenomena is not understood. We use a combination of turbidimetry measurements and lightscattering (static and dynamic) techniques to measure cloud point curves andcharacterise micellar behaviour prior to clouding.

Polylactides (PLA) are thermoplastic materials known for their biodegradability and biocompatibility, and therefore mostly utilized in biomedical applications. PLA-containing block copolymers further expand their application to include commodity materials and even advanced nanoporous materials. This research part of the thesis focuses on the synthesis and characterization of PLA-containing block copolymers, as well as their corresponding stereocomplexes formed by mixing block copolymers containing PLLA and PDLA segments. This work is divided into three parts. First, by using “living” anionic polymerization of styrene (St) and 2-vinylpyridine (2VP) followed by subsequent ethylene-oxide (EO) termination, well-defined hydroxyl-terminated polystyrene (PS) and poly(2-vinylpyridine) (P2VP) were synthesized. The resulting homopolymers were characterized by 1H nuclear magnetic resonance (NMR), size-exclusion chromatography (SEC), and infrared (IR) spectroscopy. The molecular weights were determined by SEC to be 6,200 and 5,500 g.mol-1 for PS and P2VP, respectively. In the second part, the two homopolymers, PS-OH and P2VP-OH were used as the macroinitiators for the ring-opening polymerization (ROP) of D- and L-lactides (D/L-LA) to obtain PS-b-PDLA and P2VP-b-PLLA, respectively. The targeted molecular weights of PLA blocks were varied to be 5,000, 7,000, and 10,000 g.mol-1 In the final part, quantitative stereocomplex formation was achieved by mixing PS-b-PDLA and P2VP-b-PLLA having equimolar PLAs segments. The physical and chemical properties of the diblockcopolymers and their corresponding stereocomplex, as well as the influence of varying the molecular weights of PLA blocks, were investigated by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and circular dichroism (CD) spectroscopy.

No description available.

De nos jours, la polymérisation par voie photochimique connaît un grand essor dans différents domaines académiques et industriels comme en témoigne son nombre croissant d’applications. Les photopolymères sont omniprésents dans plusieurs domaines tels que les revêtements, le domaine dentaire, les implants chirurgicaux, les encres, l’impression 3D… Cependant, les avancées réalisées par rapport à cette voie de synthèse de matériaux polymères restent limitées et nécessitent encore plus de recherches et de développements. Cette nouvelle génération de polymères synthétisée par voie photochimique présente l’avantage d’être beaucoup plus écologique que leurs équivalents thermiques. En effet, leur préparation implique moins d’énergie que les autres techniques de synthèse de matériaux polymères. L’élaboration de polymères par voie photochimique est également plus avantageuse en termes de temps nécessaire pour la polymérisation. Moins de composés organiques volatils sont émis car la formulation ne contient que très peu voire pas du tout de solvant. Seules les zones irradiées sont polymérisées ce qui permet d’avoir un bon contrôle spatial de la polymérisation.De nombreuses recherches ont déjà été menées dans ce domaine en utilisant principalement les rayons ultraviolets. Cependant, cette gamme de longueurs d’onde peut être nocive pour la santé. De surcroît, les sources de rayonnement UV sont très énergivores et potentiellement toxiques. Par conséquent, cette technique risque de ne plus aller de pair avec les exigences environnementales actuelles. En parallèle, peu de systèmes photoamorceurs ont montré leur efficacité dans le domaine des longueurs d’onde du visible car ils nécessitent souvent des énergies beaucoup plus élevées.C’est ainsi que l’on s’est intéressé dans le cadre de cette thèse au développement de nouveaux systèmes photoamorceurs plus respectueux de l’environnement et plus efficaces pour amorcer les réactions de polymérisations radicalaire ou cationique sous lumière visible (conditions douces).La lumière visible présente plusieurs avantages par rapport à la lumière ultra-violette. En effet, une faible nocivité a été constatée ainsi qu’une faible consommation énergétique. Plusieurs dispositifs d’irradiation dans le visible ont été utilisés : des lampes halogènes, des diodes électroluminescentes (LED) … Plus intéressant encore, l’utilisation des LED émettant dans la gamme du visible présente un grand intérêt. Elles sont caractérisées par une faible consommation énergétique, un faible coût, une longue durée de vie, une forme compacte …L’utilisation des LED nécessite clairement d’améliorer la performance des systèmes photoamorceurs. Ainsi, l’étude de l’efficacité de nouveaux systèmes photoamorceurs pour la polymérisation radicalaire et/ou cationique sous irradiation de lumière visible à l’aide des LED est au cœur de ce présent sujet de thèse. Notre projet de développement des nouveaux photoamorceurs visibles se base essentiellement sur les approches suivantes : • Une bonne absorption de la lumière visible par les photoamorceurs (avec des coefficients d’extinction molaires élevés)• Un bon recouvrement entre le spectre d’absorption du nouveau photoamorceur et celui d’émission de la source d’irradiation utilisée• Utilisation de sources d’irradiation à faibles intensités (LED)• Développer des photoamorceurs hydrosolubles et efficaces pour amorcer les polymérisations dans l’eauPour les travaux menés au cours de cette thèse, on s’est intéressé à différentes familles de photoamorceurs afin d’établir la relation entre la structure, la réactivité et l’efficacité d’amorçage de réactions de polymérisation radicalaire, cationique ou pour la formation de réseaux interpénétrés de polymères.Ces travaux se divisent en deux grandes parties: une première est à caractère académique tandis qu’une seconde partie porte sur une étude appliquée dans le domaine dentaire. [...] / Nowadays, the photopolymerization processes are omnipresent in various academic and industrial fields such as the dental domain, surgical implants, 3D printing … However, the advances realized for this new way of polymer synthesis remain limited and require more developments.The polymers synthesized by photochemical process have the advantage of being more ecological than the thermal equivalents. Indeed, their preparation involves less energy than the other techniques of polymer synthesis. The elaboration of polymers by photochemical way is also more advantageous in terms of time required for the polymerization and fewer volatile organic compounds are emitted in the atmosphere. Moreover, only the irradiated zones are polymerized which allows a better spatial control of the polymerization. Several searches were already led in this domain by using mainly ultraviolet rays. However, this range of wavelengths could be harmful for the health. Besides, the UV sources are energy consuming. Consequently, this technique is no longer in agreement with the current environmental requirements. In parallel, few photoinitiating systems showed good efficiency in the visible wavelength range.In this context, we have been interested in the development of new photoinitiating systems more environment-friendly and more efficient to initiate radical, cationic and anionic polymerization under visible light irradiation.The visible light presents several advantages compared to the ultraviolet light. Indeed, it is less harmful and lower energy consuming. Particularly, light emitting diodes (LED) are interesting because they are compact and therefore easy to use, long lasting, no mercury is involved for the manufacturing … Thus, the performances improvement of the photoinitiating systems efficient upon visible LED irradiation is clearly required In this regard, the study of new high performances photoinitiating systems for radical, cationic and anionic polymerization under visible LED irradiation is at the core of the current PhD project.Our development project was based essentially on the following approaches: • Good absorption properties of the developed photoinitiators • The best matching between the absorption spectrum of the photoinitiator and the emission spectrum of the irradiation device• Use of LEDs • Development of water soluble photoinitiators for photopolymerization processes in aqueous medium.We were interested in various chromophore families in order to establish the relationship between the structure, the reactivity and the efficiency of the developed photoinitiating systems.The results obtained could be divided into two big parts: the first one has an academic character whereas the second part concerns an applied study in the dental domain.For the first part, various families of visible chromophores were introduced as high performances photoinitiators for radical photopolymerization in the visible range: i) camphorquinone derivatives ii) acylsilanes iii) naphthalimides iv) diketopyrrolopyrroles. Cationic photopolymerization has been studied also through the development of a new iodonium salt and across the use of new photoredox catalysts upon visible LED irradiation. And finally, new photobase generators have been developed for anionic polymerization upon near UV and visible LED irradiation.In the second part, a new class of photoinitiators based on silylglyoxylate structure have been introduce as efficient systems for the radical photopolymerization initiation process upon blue light and applied for the dental field. [...]

This dissertation is focused on synthesis, characterization and formation mechanism of anionic-surfactant-templated mesoporous silica (AMS). Structural control mechanisms of AMS are investigated. First, different ionization degree of anionic surfactant affected by the acidity or alkalinity of the synthesis system gives rise to different charging density of micelles and therefore determines the organic/inorganic interface curvature, producing mesophases from cage-type to cylindrical, bicontinuous and lamellar. Second, mesocage/mesocage electrostatic repulsive interaction affects the formation of cage-type mesostructure, which is derived from a full-scaled synthesis-field diagram of AMS. The mesocage/mesocage interaction changes with charge density of mesocages and gives rise to their different packing manners. Third, the structural properties of AMS materials could be tuned by molecular features of surfactant and co-structure-directing agent (CSDA). The pore size of AMS is found to be controlled by alkyl chain length, ionization degree of surfactant and the CSDA/surfactant ratio. Alkyl chain length of surfactant determines size of micelles and thus mesopores. Larger ionization degrees of anionic surfactant give rise to smaller pore sizes due to thermodynamic coiling of alkyl chains of surfactant. The hydrophobic interactions between the pendant organic groups of CSDA on the silica wall and the hydrophobic core of the micelles drive a contraction of the mesopores. A mesoporous silica with novel bicontinuous cubic Pn-3m structure has been prepared using a diprotic anionic surfactant. 3d-reconstruction of the structure shows that it is bicontinuous composed of an enantiomeric pair of 3d mesoporous networks that are interwoven with each other, divided by a D surface. Inverse replication suggests the possible presence of ordered complimentary micropores in the material.

Anionic surfactants are wildly used in many industrial and household applications. Because anionic surfactants are used so widely, significant attention has focused on the removal of these contaminants from wastewater. Among various treatment techniques, biofiltration, such as trickling filter technologies, has been employed in many wastewater treatment plants (WWPTs) to remove anionic surfactants. However, current knowledge of the efficacy of trickling filter to remove anionic surfactants from wastewaters is limited. The present study characterized the performance of a high rate (i.e. roughing) trickling filter to remove anionic surfactants both at lab-scale and pilot-scale. Lab-scale tests investigated the biodegradation of anionic surfactants under controllable conditions were compared with those from previous studies by others. Pilot-scale tests investigated the efficacy of a trickling filter at removing anionic surfactants from a wastewater over an extended period of time. The data from the pilot-scale tests were used to model the performance of trickling filter at removing anionic surfactants from the wastewater, using first order and modified Velz models. The lab-scale tests indicated that high molecular weight anionic surfactants degrade faster than the low molecular weight surfactants. The biodegradation rates observed in the present study were similar to those from pervious studies by others. The pilot-scale tests indicated that roughing trickling filter could remove 11% to 29% of anionic surfactants and 4% to 22% of COD from the wastewater. Higher molecular weight anionic surfactants were more degradable. The experimental data could be accurately modeled using the modified Velz model (R² value more than 0.9). The degradation rates of modified Velz model for total anionic surfactants, high molecular weight anionic surfactants and COD were 0.053±0.0057, 0.088±0.0048 and 0.119±0.0111 (mIs)0.5 respectively. The pilot-scale test results indicated that a high rate (i.e., roughing) trickling filter was not capable of effectively removing anionic surfactants in the primary effluent at Lions Gate WWTP because a relatively large trickling filter area would be required to achieve the required surfactant removal efficiency.

O σκοπός της εργασίας αυτής ήταν η σύνθεση νέων αστεροειδών τριπολυμερών, τύπου An(B-C)n διαφόρων μοριακών δομών, με την τεχνική του «ζωντανού» ανιονικού πολυμερισμού. Αναπτύχθηκε μια μεθοδολογία τεσσάρων διαδοχικών σταδίων σε αντίδραση διαλείποντος έργου η οποία δίνει προϊόντα καθορισμένης μοριακής αρχιτεκτονικής. Η μέθοδος αυτή είναι επέκταση της μεθόδου in-out που χρησιμοποιήθηκε για την σύνθεση ετεροκλαδικών συμπολυμερών αστεροειδών τύπου ΑnBn. Τα νέα αστεροειδή τριπολυμερή Αn(B-C)n αποτελούνται από ένα πυρήνα διασταυρομένων μονομερών από τον οποίο εξέρχονται δύο ειδών κλάδοι θεωρητικά ίσου αριθμού, ήτοι κλάδοι ομοπολυμερούς Α και κλάδοι δι-συσταδικού συμπολυμερούς (B-C). Για το σκοπό αυτό χρησιμοποιήθηκε μια ποικιλία μονομερών και παραγόντων συνένωσης προκειμένου να επιτύχουμε το επιθυμητό αποτέλεσμα. Χρησιμοποιήθηκαν διφορετικοί πυρήνες των αστεροειδών τόσο στη φύση (διβίνυλοβενζόλιο, διμεθακρυλικός αιθυλενο-γλυκολεστέρας) όσο και στις διαστάσεις (μίγμα διβίνυλοβενζολίου/στυρενίου) προκειμένου να μελετηθεί η επίδραση που φέρουν. Η μεθοδολογία που χρησιμοποιήθηκε δίνει τη δυνατότητα του σταδιακού χαρακτηρισμού των προϊόντων ο οποίος ήταν ουσιώδης για τον τελικό χαρακτηρισμό των τριπολυμερών. Για το μοριακό χαρακτηρισμό πρόδρομων και τελικών πολυμερών χρησιμοποιήθηκαν οι τεχνικές της χρωματογραφίας αποκλεισμού μεγεθών, της στατικής σκέδασης φωτός και η φασματοσκοπία του πυρηνικού μαγνητικού συντονισμού (1H-NMR). Επιπλέον για λόγους σύγκρισης ιδιοτήτων μεταξύ γραμμικών και αστεροειδών, συντέθηκαν γραμμικά ABC τριπολυμερή χρησιμοποιώντας την μέθοδο της διαδοχικής προσθήκης. Τα τελικά πολυμερή καθαρίστηκαν από τυχόν προσμίξεις με την τεχνική της soxhlet και χρησιμοποιώντας ως διαλύτη κυκλοεξάνιο. Μελετήθηκαν οι μηχανικές ιδιότητες των ετεροκλαδικών αστεροειδών συμπολυμερών σε σύγκριση με τα αντίστοιχα γραμμικά τριπολυμερή, με σκοπό να διερευνηθεί η επίδραση της αρχιτεκτονικής στις ιδιότητες αυτές. Επιπλέον εξετάσθηκε και ο μικροφασικός διαχωρισμός τόσο των γραμμικών όσο και των αστεροειδών τριπολυμερών και ο ρόλος που παίζουν η αρχιτεκτονική και τα μοριακά χαρακτηριστικά των πολυμερών. Η πραγματοποίηση πειραμάτων δυναμικής μηχανικής ανάλυσης καθώς και διαφορικής θερμιδομετρίας σάρωσης σε αστεροειδή πολυμερή πολύστυρενίου, πολύ(μεθακρυλικού εξυλεστέρα) και πολύ(μεθακρυλικού μεθυλεστέρα) και στα αντίστοιχα γραμμικά τους πολυμερή οδήγησαν σε ενδιαφέρον συμπεράσματα. Έγινε σαφές πως η δομή και το μοριακό βάρος επηρεάζουν τις ιδιότητες των πολυμερών. / The subject of this research was the synthesis of star-shaped terpolymers An(B-C)n, using the anionic living polymerization. A 4-step methodology in patch reaction was developed which gives polymers of specific molecular structure. This method is expansion of the in-out method which is used to synthesize heteroarm-star copolymers AnBn. The new star terpolymers consist of a core from cross-linked monomers from which derive two kind of branches theoretically equal in number. One is branches of homopolymer A and the other is branches of diblock copolymer (B-C). For this aim a variety of monomers and cross-linking agents was used. Different cores were made on the nature (DVB,EGDMA) and the size (DVB/St) in order to investigate their effect. Through the synthetic methodology we were able to molecular characterize each step which was vital for the final polymer. The polymers were well characterized through specific techniques. In order to measure the molar mass (Mw and Mn) and the polydispersity, I (Mw/Mn), we used Size Exclusion Chromatography (SEC) technique. The number of the branches was calculated by the Static Light Scattering (SLS) technique. Nuclear Magnetic Resonance spectroscopy (1 H-NMR) was used to calculate the percentage of each homopolymer to the terpolymer. Moreover in order to compare the properties of star and linear terpolymers, ABC linear terpolymers were synthesized by sequential addition. The final polymers were purified through the soxhlet technique with cycloexane. The properties of heteroarm star-like terpolymers were studied comparing with that of the corresponding linear terpolymers (the block and arm lengths were equal) in order to understand the effect of the macromolecular architecture on these properties. Moreover the microphase separation was examined in order to study the effect of the architecture and the molecular characteristics on the terpolymers. The Dynamic Mechanical Analysis (DMA) and Differential Scanning Calorimetry (DSC) experiments on linear and star terpolymers with polystyrene (PS), poly(hexylmethacrylate) (PHMA) and poly(methylmethacrylate) (PMMA) result in interesting conclusions. These conclusions gave us a clear proof that the molecular characteristics and the architecture of the polymers infect their properties.