The research topic of liquid drop interaction with solid surfaces is being actively pursued to gain in-depth understanding of several practical cases such as the impingement of fuel spray droplets on surfaces like combustion chamber walls and piston top of an I.C. engine, heat transfer via spray impingement, ink-jet printing, etc. In most of the cases, the physical and flow properties of the liquid drop/spray may be fixed whereas it may be possible to tune the physical and chemical properties of the solid surface thereby enabling to control the interaction process. The present work belongs to the study of liquid drop-solid surface interaction process with special focus on the physical characteristics of solid surface. The thesis reports an experimental study of the dynamics of millimetric water drops impacted onto the junction of dual-textured substrates made of stainless steel. The dual-textured substrates consisted of hydrophobic (textured) and hydrophilic (smooth) portions. The entire textured portion comprised of parallel groove-like structures separated by solid posts/pillars. Two dual-textured substrates, which differ only in the geometry of their textured portions, were employed. Surface topography features of the dual-textured substrates were characterized using scanning electron microscopy (SEM) and optical surface profilometer. The wetting behavior of the textured and smooth portions of the substrates, quantified in terms of the equilibrium, advancing, and receding contact angles adopted by a water drop on the surface portions, was characterized experimentally through the methods of sessile drop formation, captive needle volume addition, and drop evaporation under ambient conditions. Free-falling water drops were impacted from a height onto the junction between the hydrophobic (textured) and hydrophilic (smooth) portions of the dual-textured substrates. A set of twelve different impact experiments were conducted on each of the target substrates with drop impact velocity (Uo) ranging from 0.37 to 1.50 m/sec. The dynamics of drop impact were captured using a high speed camera with frame rate ranging from 3000 to 10000 frames per second. From the captured frames, the temporal variations of the impacting drop parameters were measured using a MATLAB-assisted program. A systematic analysis of experimental data revealed the existence of four distinct regimes of drop dynamics on the dual-textured substrate: (a) early inertia driven drop spreading, (b) primary drop receding, (c) secondary spreading on the hydrophilic portion, and (d) final equilibrium regimes. It is shown that the drop impact dynamics during the early inertia driven impact regime remains unaffected by the dual-texture feature of the substrate. A larger retraction speed of impacting drop liquid observed on the hydrophobic portion of the substrate makes the drop liquid on the higher wettability/hydrophilic portion to advance further (secondary drop spreading). The net horizontal drop velocity towards the hydrophilic portion of the dual-textured substrate decreases with increasing drop impact velocity. The available experimental results suggest that the movement of bulk drop liquid away from the impact point during drop impact on the dual-textured substrate is larger for the impact of low inertia drops. A semi-empirical model, based on the balance of the wettability gradient, contact angle hysteresis, and viscous forces acting on impacted drop liquid on the substrate, is formulated to predict the movement of bulk drop liquid away from the impact point (ξ). A satisfactory comparison between the model predictions and the experimental measurements is reported for the variation of ξ with Uo.

Synthesis of cyclodextrin derivatives for practical applications Abstract The first part of this PhD thesis is focused on the synthesis of a series of monosubstituted tetraalkylammonium cyclodextrin (CD) derivatives. The emphasis was placed on the possible applicability of the synthetic process to multigram or even industrial scale. Monotosylation of the native cyclodextrins (-, -, -) on the primary side of the macrocycle afforded the starting materials. Derivatives with one cationic group were prepared by the reaction with aqueous trimethylamine. The reaction of the mono-Ts-CD with neat N,N,N'-trimethylethane-1,2-diamine or N,N,N'-trimethylpropane-1,3-diamine and subsequent methylation led to derivatives with the substituent bearing two cationic groups (PEMEDA- and PEMPDA-β-CD). Analogs bearing a moiety with three tetraalkylammonium sites were synthesized by reaction of mono-Ts-CD with bis(3-aminopropyl)amine with subsequent methylation. 1,3-Dipolar cycloaddition of mono-6- azido--CD with diaminoacetylenes followed by methylation led to analogs with a avariable distance of the charged substituent from the CD core. Majority of the presented reactions are straightforward, relatively high-yielding and the workup does not require chromatographic steps. The second part of the work is dealing with the...

Les milieux réactionnels issus de l’étude de la réactivité de deux types de polyols, le glycérol et le diglycérol par réaction d’estérification directe avec l’acide undécylénique, catalysée par l’acide dodécylbenzène sulfonique (ADBS). Les résultats montrent que les ystèmes polyol/acide undécylénique donnent une émulsion eau dans huile (E/H). L’ajout de l’ADBS et de l’eau formée in-situ aux systèmes polyol/acide undécylénique ont permis de réduire la taille des gouttelettes de 50 μm à moins de 1 μm et d’obtenir un système organisé (micro-réacteur). L’augmentation de la température contribue à favoriser le transfert de matière dans les systèmes émulsionnés et / ou gélifiés et d’obtenir un système monophasique, homogène et structurés. L’étude de la réaction de ces systèmes avec une approche site à site (site OH / site COOH) a montré que lorsque le nombre de sites acides carboxyliques est inférieur à celui des sites hydroxyles, la synthèse est totalement sélective en esters partiels des deux polyols (glycérol et diglycérol). Les rendements sont supérieurs respectivement à 60% en esters partiels de glycérol et à 70% en esters partiels de diglycérol. La modélisation de la cinétique de synthèses et la régression des données cinétiques ont montré que la réaction est réversible d’ordre 2 et athermique. Les énergies d’activation calculées sont de 17 kcal/mol et 16 kcal/mol respectivement pour le monoundécénoate de glycérol (MUG) et le diundécénoate de glycérol (DUG). De plus, la méthodologie de recherche expérimentale a montrée que les variables (concentration en catalyseur ADBS et température) permettent d’obtenir le MUG avec un rendement de plus de 60% et une sélectivité en MUG de 80%. Ensuite, l’étude de la réactivité de la double liaison terminale du MUG en présence de deux agents oxydants pour engendrer des molécules bolaamphiphiles simples a été réalisée par H2O2 / acide formique et acide métachloroperbenzoïque (m-CPBA). Les résultats ont montré le 10,11-dihydroxy-monoundécénoate de glycérol (MUGDiol) est obtenu par oxydation au H2O2 / acide formique et le 10,11-époxy-monoundécénoate de glycérol (MUGE) par réaction d’époxydation avec la m-CPBA. L’ouverture de la fonction époxyde par des molécules aminées permet l’observation de nouvelles molécules bolaamphiphiles : le 10-hydroxy-N-11-((2-hydroxyéthyl)amino)monoundécénoate de glycérol(bola éthanolamineglycérol) et le N,N-11-(diaminobutan)-10-hydroxymonoundecanoate de glycérol (bola diaminobutaneglycérol). L’étude des propriétés physico-chimiques de ces molécules amphiphiles et bolaamphiphiles a permis de monter que toutes ces molécules sont de solvo-surfactants actifs aux interfaces et elles réduisent la tension interfaciale de l’eau jusqu’à la limite de la solubilité dans l’eau. L’adsorption des molécules ne vérifie pas le modèle de Gibbs. Le MUG et le MUDG s’auto-assemblent dans l’eau et donnent des nano-objets (vésicules et agrégats plats) et s’adsorbent sur des surfaces polaires et solides (silice et ciment). Ces deux molécules retiennent 30% et 56% molécules d’eau et le nombre de molécules d’eau fortement liée aux têtes polaires est de 21 et 49 respectivement pour le MUG et le MUDG. Pour es molécules bolaamphiphiles pures (MUGE et bola éthanolamineglycérol), elles retiennent plus de 56% de molécules d’eau et se lient à plus 53 molécules d’eau. L’ensemble de ces propriétés physico-chimiques a permis de répondre aux problématiques industrielles et de formuler un produit de cure, un agent de démoulage et un produit anti-adhérent. / This study is of the reactivity of two types of polyols (glycerol and diglycerol) by direct esterification reaction with undecylenic acid from castor oil. This reaction was catalyzed by dodecylbenzene sulfonic acid (DBSA). The first step was to study of polyol / undecylenic acid reaction systems by physico-chemical approach. The result have shown that these systems give water-in-oil (W / O) emulsion. Adding DBSA and water formed in-situ in polyol/undecylenic acid systems have reduced droplet size from 50 microns to less than 1 μm and form an organized system (micro-reactor). Increasing temperature can simplify transfers in emulsified systems and / or melted gel and to get a monophasic and homogeneous system. The only systems and aided by water formed in-situ assists the organization and structuring of gels. The reaction study of these systems was analyzed by gas chromatography. This showed that when the number of carboxylic acid function sites is less than the hydroxyl function site, synthesis is totally selective to partial esters of the two polyols (glycerol and diglycerol). The yields are higher than 60% in partial glycerol esters and 70% in partial diglycerol esters. The kinetic modeling of this synthesis and regression of kinetic data by the software GEPASI showed that the reaction follows the reversible 2 order and it is athermic. The calculated activation energy is 17 kcal/mol for the synthesis of glycerol monoundecenoate (GMU) and 16 kcal/mol for glycerol diundecenoate (GDU), these values are close to the theoretical values and they show that the reaction is happening at room temperature. Moreover, the response of the surface methodology shows that the variables chosen for the present study are temperature and catalyst concentration have a positive effect on the yield of the GMU. This approach was used to determine the optimum conditions for producing the GMU. Second study performed was of the reactivity of the terminal double bond of the GMU in presence of two oxidizing agents H 2 O 2 / formic acid and metachloroperbenzoic acid (m-CPBA), for synthesized bolaamphiphiles molecules was performed. The H 2 O 2 /formic acid was used to oxidize the double bond of GMU in diol function of glycerol 10,11-dihydroxymonoundecenoate (GMUDiol). The m-CPBA epoxidizes the double bond of GMU to give glycerol 10,11-epoxymonoundécénoate (GMUE). The opening of the epoxide function by aminoalcohol molecules are used to generate the new molecules bolaamphiphiles molecules: the bola ethanolamineglycerol and the bola diaminobutaneglycerol. The third step was the stady of the physico-chemical properties of pure amphiphilic and bolaamphiphiles molecules. The result was shown that all molecules are solvo-surfactants molecules and they are active in the interfaces (liquid/air and liquid/solid). The curves of surface tension of water do not respect the Gibbs rule. GMU and DGMU self- assemble in water and give nano-objects (vesicles and aggregates) in diluted solutions. In hydrogel, the molecules self-assemble in lamellar phase. In this lamellar phase, the amount of water retained is 56% and the number of water molecules strongly linked to the polar heads is 49 moles of water/diglycerol monoundecenoate molecule (DGMU). All these physico-chemical properties have permit to respond to industrial problems such as water retention for the curing product, self-assembly for demoulding concrete and for surface anti-adhesion and adsorption and finally foaming required for the aged bitumen regeneration. For pure bolaamphiphiles molecules (GEMU and ethanolamineglycerol bola) reduce the interfacial tension of water to the limit of the solubility of this bola molecules in water but do not provide a critical aggregation concentration (CAC). They retain more water molecules respectively between 56% and 63% water and the number of water molecules strongly bound with two polar heads groups pure bolaamphiphiles molecules is between 42 and 53.