Poly (2-ethyl-2-oxazoline)-based amphiphilic diblock copolymer has the potential to form promising membrane materials for water purification due to the thermal stability and good solubility in aqueous solution and also for gas separation because of the presence of polar amide group along the polymer backbone. Moreover, their self-assembly into micelles renders them candidate materials as nanocarriers for drug delivery applications. In this study, a novel well-defined linear PEtOx-based amphiphilic diblock copolymer with a hydrophobic fluoropolymer, i.e., PVDF, have been successfully synthesized by implementing a synthesis methodology that involves the following four steps. In the first step, poly (2-ethyl-2-oxazoline) (PEtOx) was synthesized via living cationic ring-opening polymerization (LCROP) of 2-ethyl-2-oxazoline (EtOx) monomer. The “living” nature of LCROP allows the desirable termination to occur by using the proper termination agent, namely, water, to achieve the polymer with a terminal hydroxyl group, i.e., PEtOx-OH. The hydroxyl end group in PEtOx-OH was converted to PEtOx-Br using 2-bromopropionyl bromide via an esterification reaction. In the third step, the PEtOx-Br macro-CTA was subsequently reacted with potassium ethyl xanthate to insert the necessary RAFT agent via nucleophilic substitution reaction to obtain PEtOx-Xanthate. It s worth mentioning that this step is vital for the sequential addition of the second block via the RAFT polymerization reaction of fluorinated monomer, i.e., VDF, to finally obtain the well-defined amphiphilic diblock copolymer with variable controlled chain lengths. Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR) and Fourier Transform Infrared Spectroscopy (FT-IR) confirmed the structure of the macroinitiator and final copolymer, respectively. Size Exclusion Chromatography (SEC) determined the number-average molecular weight (Mn) and the polydispersity index (PDI) of the obtained copolymer. Furthermore, the polymorphism of the diblock copolymer characterized by X-Ray Diffraction (XRD) indicated that the copolymer displays the electroactive α-phase. The resultant amphiphilic diblock copolymer exhibits spherical micelles morphology, as confirmed by Dynamic Light Scattering (DLS) and Atomic Force Microscopy (AFM). Moreover, Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) investigated the thermal decomposition behavior of the copolymer and determined the glass transition temperature (Tg ≈ 70 °C), melting temperature (Tm ≈ 160-170 °C), and crystallization temperature (Tc ≈ 135-143 °C) of the diblock copolymer, respectively.

Nous avons étudié l'utilisation du phénomène de ségrégation de surface afin de fonctionnaliser des matériaux polystyrène (PS). L'incorporation d'un additif copolymère à blocs est réalisée dans une matrice d'homopolymère de polystyrène sous forme de film ou de particule. Quand les mélanges sont recuits dans un environnement humide le copolymère amphiphile migre à la surface pour réduire la tension de surface du matériau. Nous avons synthétisé au laboratoire trois copolymères à blocs de nature chimique différente: le PS-b-PAA (polyacide acrylique), le PS-b-PGA (polyacide glutamique) et le PS-b-PDMA (polyméthacrylate de diméthylaminoéthyle). Ces copolymères nous permettrons d’accéder à des comportements superficiels variés. Les films sont réalisés par spin-coating et les particules par polymérisation par précipitation. Ces matériaux sont ensuite caractérisés par mesure de l'angle de contact, par XPS, AFM, etc…, afin de déterminer leur fonctionnalité et leur structuration en surface. / We describe the use of surface segregation to functionalize the surface of polymeric materials. The incorporation of an additive (amphiphilic block copolymer) in a homopolymer host initially leads to its homogeneous distribution within the matrix. When annealed, directed by the decrease of the surface free energy, the surface is enriched on the additive. In our laboratory, polystyrene thin films and particles were functionalized by following this approach. We employed amphiphilic block copolymers composed of one PS block to compatibilize with the homopolymer matrix, and a second block which will bring the desired function at the surface. Thus, PS-b-poly(acrylic acid), PS-b-poly(L-glutamic acid) or PS-b-poly(L-Lysine) afford pH sensitivity and PS-b-poly(dimethylaminoethyl methacrylate) gives pH and thermo sensitivity. Contact angle measurements, X-ray photoelectron spectroscopy, atomic force microscopy, zeta potential measurement or scanning electron microscopy were carried out to characterize the materials and their responsive behavior.