Among the materials that can be treated in order to impart superhydrophobic properties are many originally hydrophilic metals. For this, they must undergo a sequential treatment, including roughening and hydrophobic coating. This contribution presents various preparation routes along with various characterization methods, such as dynamic contact angle (DCA) measurements, scanning electron microscopy (SEM) and spectroscopic techniques (FT–IRRAS, XPS, EIS). Micro-rough surfaces of pure and alloyed aluminum were generated most easily by using a modifie Sulfuric Acid Anodization under Intensifie conditions (SAAi). This produces a micro-mountain-like oxide morphology with peak-to-valley heights of 2 μm and sub-μm roughness components. Additionally, micro-embossed and micro-blasted surfaces were investigated. These micro-roughened initial states were chemically modifie with a solution of a hydrophobic compound, such as the reactive f uoroalkylsilane PFATES, the reactive alkyl group containing polymer POMA, or the polymer Teflo ® AF. Alternatively, the chemical modificatio was made by a Hot Filament Chemical Vapor Deposition (HFCVD) of a PTFE layer. The latter can form a considerably higher thickness than the wet-deposited coatings, without detrimental leveling effects being observed in comparison with the original micro-rough surface. The inherent and controllable morphology of the PTFE layers represents an important feature. The impacts of a standardized artificia weathering (WTH) on the wetting behavior and the surface-chemical properties were studied and discussed in terms of possible damage mechanisms. A very high stability of the superhydrophobicity was observed for the f uorinated wet-deposited PFATES and Teflo ® AF coatings as well as for some of the PTFE layer variants, all on SAAi-pretreated substrates. Very good results were also obtained for specimens produced by appropriate mechanical roughening and PTFE coating.

The increasing awareness of sustainability motivates the development of building materials from renewable resources. The requirements of wood-based products with improved durability, for example, an enhanced liquid repellence, is still a challenge. The aim of this thesis is to develop and study concepts to functionalize wood surfaces to obtain superhydrophobicity or superamphiphobicity, i.e. extreme liquid repellence of both water and oils. Birch and acetylated birch veneer samples were surface-modified by hydrophobized silicone nanofilaments. Specifically, birch samples surface-modified by fluorinated silicone nanofilaments (F-SMB) showed superamphiphobicity, which repelled water, ethylene glycol and hexadecane with static contact angles greater than 150° and roll-off angles lower than 10°. Birch and acetylated birch samples surface-modified by non-fluorinated silicone nanofilaments (SMB and SMAB) showed superhydrophobicity with static contact angles greater than 160° towards water, even for samples prepared using the shortest silicone nanofilaments reaction time of 1 h. In liquid uptake measurements submerging the F-SMB in water, ethylene glycol and hexadecane, a superamphiphobic plastron effect was observed which indicates that the wood surface was in Cassie-Baxter state. The plastron reduced the liquid uptake rate and extent depending on the interactions (diffusion and solubility) between the liquid and the silicone nanofilaments. The F-SMB showed good self-cleaning properties towards water and hexadecane. In multicycle Wilhelmy plate measurements, the SMB showed a lower water uptake than that of the acetylated samples, while the SMAB showed the lowest water uptake, i.e. a pronounced increased water resistance, due to a combined effect of acetylation and surface modification. In addition, the SMB exhibited more color change than the SMAB, which was caused by the release of hydrochloric acid during the surface modification process. / Den ökande medvetenheten kring hållbarsamhällsutvecklingmotiverarutveckling avbyggmaterial från förnybara resurser. Kraven på träbaserade produkter med förbättrad beständighet, exempelvisennödvändig vätskeavvisandeförmåga, är fortfarande en utmaning.Syftet med dennaavhandling äratt utveckla och studera koncept för attfunktionalisera träytorför att uppnåsuperhydrofobicitet ochsuperamfifobicitet, dvs en extrem vätskerepellerande egenskap för både vatten och oljor.Björk-och acetyleradebjörkfanérproverytmodifierades med hydrofobiserad silikon-nanofilament. Specifikt visade björk ytmodifierademedfluorerade silikon-nanofilament (F-SMB) superamfifobicitet, som repelleradevatten, etylenglykol och hexadekan med kontaktvinklar större än 150° och avrullningsvinklar lägre än 10°. Björk-och acetyleradebjörkproverytmodifierademedicke-fluorerade silikon-nanofilament (SMB och SMAB) visade superhydrofobicitet med kontaktvinklar större än 160° förvatten, även förprover framställda medkortast reaktionstid på 1 timme.Vid vätskeupptagningsmätningargenom att sänka F-SMB i vatten, etylenglykol och hexadekanobserverades en plastroneffekt som indikerade att träytan var i Cassie-Baxter-tillstånd. Plastronen minskade F-SMB vätskeupptagningshastighet och -nivåberoende på växelverkan(diffusion och löslighet) mellan vätskan och silikon-nanofilament. F-SMB uppvisadegoda självrengörande egenskaper förvatten och hexadekan.Vidmulticykel Wilhelmy-mätningarvisade SMB ett lägre vattenupptag än det acetylerade träet, medan SMAB visade denlägsta vattenupptagningen,det vill säga en mycketmärkbar ökad vattenavvisning, tack vareav en kombinerad effekt av acetylering och ytmodifiering. Dessutom uppvisade SMB en störrefärgförändring än SMAB, orsakad av frisättningen av saltsyra under ytmodifieringsprocessen. / <p>QC 20201113</p>

En ”lätt-att-rengöra” yta definieras som en yta som stöter bort vatten och smuts. I detta projekt har klarlack med olika sammansättningar studerats i syfte att introducera egenskapen ”lätt-att-rengöra”. För att uppnå denna egenskap måste beläggningen vara superhydrofob och oleofob. Detta innebär att kontaktvinklarna för både vatten (WCA) och dijodmetan (DMCA) måste vara över 150°. En hybrid sol-gel-metod valdes för detta projekt på grund av dess många fördelar som kontroll av ytmorfologi, enkel inkorporering av nanopartiklar och organiska komponenter i nätverket samt förmåga att bilda ett antal kompositioner. Hybrid sol-gelfilmerna, som innehåller både organiska och oorganiska komponenter, ger mekanisk beständighet, flexibilitet och förmåga att härda vid låga temperaturer. De organiska komponenterna fyller porerna i den oorganiska oxidkedjan, vilket gör att det hybridorganiskt-oorganiska materialet når slutlig densitet vid lägre temperatur. Både hydrofoba och hydrofila kiselnanopartiklar studerades för att undersöka vilken av dem som bäst inkorporeras i filmen. Den högsta uppnådda hydrofobiciteten och oleofobiciteten var av ett prov med 133° WCA och 152° DMCA. Provet bestod av en organisk och oorganisk komponent såväl som hydrofoba kiselnanopartiklar. / An easy-to-clean surface is defined as a surface that repels water and dirt. In this project, clearcoats with different composition have been studied in the process of introducing easy-to-clean properties in the coating. To achieve these properties the coating needs to be both superhydrophobic and oleophobic. This means that the contact angles against both water (WCA) and diiodomethane contact angle (DMCA) should be above 150 °. A hybrid sol-gel approach was chosen for this project due to the several advantages it provides such as, control of surface morphology, easy incorporation of nanoparticles and organic components into the network and ability to form a range of compositions. The hybrid sol-gel films, which contain both organic and inorganic components, provide mechanical resistance, flexibility, and ability to cure at low temperatures. The organic compounds fill the pores between the inorganic oxide chain; hence, the hybrid organic-inorganic material reaches final density at lower temperature. Both hydrophobic and hydrophilic silica nanoparticles were studied to analyze which of them would be best incorporated into the film. The highest hydrophobicity and oleophobicity achieved were by a sample with 133° WCA and 152° DMCA. The sample consisted of an organic and inorganic component as well as hydrophobic silica nanoparticles.

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.