Raspberry-like polystyrene particles were fabricated through the covalent linkage of small epoxy-functionalized polystyrene particles (PS-GMA) with large amino-functionalized polystyrene particles (PS-NH2). These covalent bonds yielded more stable and robust particle clusters than would be anticipated from non-covalent interactions. While the structures of these raspberry-like particles provided them with a dual-scale hierarchical roughness and re-entrant sites, they were further functionalized with a fluorinated random copolymer to provide them a low surface tension. The fluorinated random copolymer used to functionalize these raspberry-like particles was poly(glycidyl methacrylate20%)-co-2(perfluorooctyl)ethyl methacrylate80%)25 or P(GMA20%-co-FOEMA80%)25, where the subscript 25 denotes the total number of the respective GMA and FOEMA units, while the subscript 20% and 80% denote the molar fractions of GMA and FOEMA, respectively. The epoxy groups of the GMA units could react with the amino groups of the raspberry-like particles, thus incorporating the fluorinated polymer onto the surfaces of the raspberry-like particles. In addition, the FOEMA component provided the particles with enhanced amphiphobicity. Subsequently, these fluorinated raspberry-like particles were cast onto glass slides to demonstrate their superamphiphobic properties. These coatings exhibited superhydrophobic behavior when they were tested against water droplets. Additionally, the oil-repellency of these coatings was tested against various liquids, including diiodomethane, cooking oil, and hexadecane. The coatings exhibited superoleophobic behavior against diiodomethane and cooking oil, as well as highly oleophobic behavior against hexadecane. This work demonstrates a simple and efficient route for the fabrication of superamphiphobic surfaces. Additionally, these surfaces are among the first examples of coatings prepared via self-assembly techniques that exhibited high repellency against hexadecane. These materials could have potential in various applications that require protection of a surface against wetting by either water or oils. / Thesis (Master, Chemistry) -- Queen's University, 2013-10-18 12:36:39.039

The current study is focused on the characterization of four natural leaf species (quaking, bigtooth and columnar european aspen as well as black locust) possessing a unique dual-scale cuticle structure composed of micro- and nano-scale asperities, which are able to effectively resist wetting (superhydrophobic), characteristic of The Lotus Effect. Scanning Electron Microscopy (SEM) was used to track the growth and evolution of their distinctive nano-scale epicuticular wax (ECW) morphologies over one full growing season. In addition, the stability of their superhydrophobic property was tested in various environments. It was determined that the long-term stability of these surfaces is tentatively linked to various environmental stress factors. Specifically, a combination of high temperature and humidity caused the degradation of nano-scale asperities and loss of the superhydrophobic property. The dual-scale surface structure was found to provide a suitable template for the design of future superhydrophobic engineering materials.

The current study is focused on the characterization of four natural leaf species (quaking, bigtooth and columnar european aspen as well as black locust) possessing a unique dual-scale cuticle structure composed of micro- and nano-scale asperities, which are able to effectively resist wetting (superhydrophobic), characteristic of The Lotus Effect. Scanning Electron Microscopy (SEM) was used to track the growth and evolution of their distinctive nano-scale epicuticular wax (ECW) morphologies over one full growing season. In addition, the stability of their superhydrophobic property was tested in various environments. It was determined that the long-term stability of these surfaces is tentatively linked to various environmental stress factors. Specifically, a combination of high temperature and humidity caused the degradation of nano-scale asperities and loss of the superhydrophobic property. The dual-scale surface structure was found to provide a suitable template for the design of future superhydrophobic engineering materials.

Cette thèse porte sur la fonctionnalisation de surface par microstructuration laser. L’étude expérimentale a consisté à texturer des surfaces d’acier inoxydable avec une source laser impulsionnelle à fibre dopée Yb (1030 nm, 300 fs), dans le but de contrôler leur mouillabilité et de les rendre superhydrophobes. Par une optimisation des conditions d’irradiation, il est possible de conférer à la surface une structuration à double échelle de rugosité. Des structures d’une dizaine de micromètres sont réalisées par ablations successives selon un motif de lignes croisées, sur lesquelles se forment des nanostructures auto-organisées. La simulation du couplage de l’énergie dans la cible a permis de déterminer les paramètres opératoires pour limiter l’accumulation thermique en surface. L’étude fait clairement apparaître le rôle de la texturation dans l’apparition du caractère superhydrophobe de la surface, tout en soulignant l’influence des propriétés physico-chimiques du matériau. / This PhD thesis is about surface functionalization by laser microstructuring. The experimental study consists in texturing stainless steel surfaces with a pulsed Yb fibre laser source (1030 nm, 300 fs), in order to control their wettability and confer to them superhydrophobic properties. With an optimization of the irradiating conditions on the target, it is possible to confer to the surface a dual-scale roughness. By successive ablations according to a pattern of crossed lines, microstructures in the range of tens of micrometres are realized, on which self-organized nanostructures are superimposed. Simulation of the energy coupling in the material allows to determine the process parameters to be used, in order to limit the thermal accumulation and avoid the melting of the surface. This study reveals the role of the laser texturing in the apparition of the superhydrophobic character and emphasizes the influence of the physicochemical properties of the material.