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In nanotechnology one very interesting theme is to combine different types of materials by inclusion of nanoparticles in polymer particles thereby enhancing for example mechanical properties, barrier properties and chemical resistance of the resulting films or foams. Several types of nanofillers exist of which an important naturally occurring one is montmorillonite (MMT) clay. MMT has a high aspect ratio and can be made hydrophobic by chemical modification. The MMT is expected to be dispersible in a polyol. In case the inorganic filler (either encapsulated to as it is) is present in one of the components of the polyurethane formation an elegant route towards hybrid polyurethanes can be envisioned. By using polyols in combination with inorganic fillers (e.g. clay, BaSO4 or CaCO3) in polyurethane foam manufacturing, cell-openness and the hardness or load bearing properties of the flexible foam are improved. It is observed that the inorganic fillers act as nucleating agents during the foaming process. By introducing the particles in the foam, a heterogeneous morphology is created and the particles can act as sites for localized stress concentration. The particle absorbs the fracture energy and therefore increases the toughness of the foam. Instead of inorganic fillers, organic fillers can be used in a similar way. The preferred method at Dow Chemicals is to synthesize the polymeric material in-situ, by a free radical dispersion polymerization in a liquid polyether polyol media. At the moment it is most common to use styrene-acrylonitrile copolymer polyol dispersions. The goal of this thesis is to encapsulate montmorillonite (MMT) clay in polymer using the polyol as the preferred continuous phase and subsequently as one of the reagents for producing polyurethane foams. The first step in the research was to explore the possibilities of exfoliating native and modified MMT in polyol liquids. Exfoliation is needed before any encapsulation can be attempted and is described in chapter 2. We found that dispersing the MMT in various polyols leads to birefringence due to formation of liquid crystals. The behaviour of the MMT in triethanol amine (TEA) appeared to be complex and maybe not fully understood. But the observation of birefringence over time and flow induced birefringence indicates that some platelets have exfoliated towards single platelets or stacks of a few platelets. From the rheological and x-ray diffraction (XRD) data and observations in the transmission electron microscope we found that the cloisite 30 B exfoliates in polyol 767. The native clay gives broad diffraction peaks in the polyol 767 and IP 3040, giving rise to the idea that the clay is intercalated. Subsequently we started exploring our envisaged encapsulation technique; dispersion polymerization in the presence of clay, the results are presented in chapter 3. We started with clay free recipes in order to explore the possibilities of free radical dispersion polymerization in polyols and also ethanol. Monodisperse polystyrene particles of 2 µm were obtained in ethanol at 70 0C. Dispersion polymerizations at 70 0C in TEA and the polyols lead to agglomeration and in the first hour control over particle formation is lost. Experiments with higher stirring rates did not result in stable dispersions. By increasing the polymerization temperature to 121 0C, colloidally stable polystyrene particles in TEA were obtained. Mixtures of ethanol and TEA led to stable polystyrene particles at 70 0C. We believe that the reduced viscosity (by the dilution with ethanol) or by increasing the temperature provides the key to the formation of stable polystyrene particles. By using 120 0C stable dispersion of polystyrene in polyols are formed. Subsequently we attempted to encapsulate the clay in polyol as a polymerization medium, as shown in chapter 4. First attempts to encapsulate native clay in the polyols led to aggregation. We modified the faces of the clay platelets by using electrostatic interaction (ion exchange) or the side of the clay platelet by a covalent bond between the hydroxyl group of the clay and a silane. Increase in d-spacing of the clay indicated that the clay was modified with TMC-10. The clay containing polymer particle sizes ranged from 500 nm- 2 µm and was broader than that of pure polystyrene. Thermogravimetric analysis (TGA) indicated that these particles were thermally more stable than the pure pSt particles. In case of the edge modified clay different morphologies were found for the same recipes. The dumbbell shaped particles resembled the morphologies found with the face modified clay. TGA and XRD results indicate that the clay is present in the pSt phase and is fully exfoliated. Now that clay containing polymer dispersions in polyols can be obtained the next step is to use these dispersions in polyurethane formation. In chapter 5 some preliminary experiments are shown using different dispersions. Polyurethane foams with clay were prepared by adding clay containing TEA and polymeric methylene difenyl diisocyanaat (MDI). It was found that reproducing the properties of foam, even without particles, seemed already very challenging. Therefore chapter 5 might be seen as a first attempt to prepare foams with encapsulated particles but no sound conclusions can be drawn yet. After adding the clay or polymeric particles to the recipe, scanning electron microscopy (SEM) images revealed a disrupted foam structure. By using dynamical mechanical thermal analysis (DMTA) an attempt was made to investigate the storage modulus of the foam. A decrease was found after the incorporation of clay or polymer particles. Also the Tg of the foam changed due to the addition of clay. This effect was less when the clay is added in the foam incorporated in polymeric particles. If the clay is still accessible during the foam formation, as in the case in the arrangement of the armoured particles, an influence on the thermal properties of the PUR foam is observed. From this exercise in producing particle containing foams it is concluded that lab scale foam production is very difficult to reproduce. With some caution however we can see that the presence of (clay containing) particles does affect the properties of the foams and that the accessibility of the clay for the reagents might be an important factor.

In light of the sustainable development, demands on polymeric materials with respect to their efficiency, ‘environmental friendliness’, etc. have increased. The service lifetime of materials would benefit from their ability to retain functioning upon damage or wear–off. Therefore, self-healing materials, having this ability, have been of the increasing research interest during the past decade. In the field of polymeric coatings, apart from sustaining the structural integrity of material, one important aspect in prolonging the service lifetime is retaining a certain amount of functional groups at different interfaces after the damage in a self-replenishing fashion. Low-adherence coatings, prepared via surface-segregation of low surfaceenergy groups during the curing process, are widely used today for their water/oil repellency, making them easily cleanable. For such coatings, low surface-energy additives are usually species containing perfluoroalkyl group at one, and hydroxyl group (or any other group that reacts with the crosslinker or resin) at the other end of a molecule. The service lifetime of these materials suffers from having a very thin fluorine-rich layer (approximately 20 nm), which can easily be removed by damage or wear off, and therefore the lowadherence character eventually may disappear. Herewith self-replenishing low-adherence coatings are those able to retain their low surface energy upon damage by recovering a sufficient amount of low surface-energy species at newly created surfaces. To summarize the findings of this research, the surface created after the damage will fully replenish in fluorinated groups if: • the bulk of the coating contains a sufficient amount of fluorinated groups • the mobility of these fluorinated groups is sufficient • the driving force for their movement towards the new interface is substantial The approach we have taken is to relatively homogeneously distribute fluorinated species that contain a long polymer spacer throughout the bulk of a film. In the case of a surface damage, that leads to the loss of the top layers of a coating, these species can reorient or even move from sublayers in order to minimize the new air/film interfacial tension. Thus the low adherence character can be sustained. The synthesis of well-defined perfluoroalkyl-end-capped precursors was performed via ‘living’ ring-opening polymerization of e-caprolactone with perfluoroalkyl-alcohol used as initiator, as described in Chapter 2. These fluorinated species were able to segregate at the surface of coatings during the curing of a film. The introduction of a polymer spacer facilitated their miscibility with the coating formulation, thus the bulk level of fluorine could be increased when compared to coatings containing fluorinated species that lack spacer as shown in Chapters 4 and 5. Once the top layer of a coating was removed by means of microtoming, the fluorinated species were reorienting spontaneously towards the new air-film interface. The F/C ratio remained similar to that of the original surface as shown by angle resolved XPS. Furthermore, the introduction of a polymer spacer appears to be the key point of the replenishing process, because it enabled the mobility of perfluoroalkyl group, as shown in Chapter 5. The driving force was the difference between the surface tension of fluorinated groups and the new interface, as briefly discussed in Chapter 2. The reorientation and movement of fluorinated species that are exposed directly at the new interface, as a result of damage, alone is not sufficient for the replenishing process. Movement of fluorinated species from sub-layers of network towards the new interface is a result of the mobility of the coating network as well. When the coating has a Tg well below room temperature, the replenishing process is autonomous. However, coatings with the Tg above room temperature do not have the ability of autonomously replenishing in a rapid fashion. Relatively fast replenishing can be triggered by the increase of temperature as described in Chapter 6. Microtoming in combination with XPS and force-displacement measurements were used to characterize the replenishing of ‘high-Tg’ coatings after annealing. The self-replenishing of low surface-energy groups placed on the dangling chains of a coating network is a process that can be further employed for sustaining different surface functionalities in a self-healing fashion.

The successful preparation of waterborne anti-corrosion coatings based on maleic anhydride containing copolymers is described in this thesis. To obtain good anticorrosion coatings, three different properties should be present in a coating system; they should display good mechanical properties, good adhesion properties, and good barrier properties. These properties are in practice obtained by applying different layers, each with their own characteristics. In this research the aim was to combine these different properties into one polymer chain. With this "one stone, multiple birds" strategy, a single coating layer should serve as a protective system. To combine different properties into one polymer chain, different strategies can be followed. One is the use of block copolymers, each block with its own specific feature. Another approach is the random incorporation of functional groups into the polymer main chain. Both approaches were explored in this thesis. For this purpose, maleic anhydride was chosen as a monomer, since this monomer is known to be very reactive with a wide variety of different compounds. Because maleic anhydride does not homopolymerize in radical polymerizations, different comonomers were used to obtain the desired copolymers. Alternating copolymers of maleic anhydride with a-olefins were obtained by free radical polymerization. Both block-copolymers and homocopolymers based on alternating styrene and maleic anhydride (PSMA) were obtained with Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. Block copolymers were obtained either by using different monomers or by modifying synthesized PSMA prior to synthesizing the second block. Furthermore, both PSMA obtained via RAFT polymerization and a commercially available PSMA were partially imidized to increase the hydrophobicity of the polymer as well as its stability in the water phase. Furthermore, a commercially available polybutadiene with grafted maleic anhydride (PBDMA) was studied as well. Stable, surfactant-free latexes could be prepared by partially ammonolizing the anhydrides of the different copolymers in acetone, followed by addition of this acetone solution to water and evaporation of the acetone. The obtained polymer particle diameters were in the order of 100 to 200 nm, as observed with atomic force microscopy, transmission electron microscopy and dynamic light scattering, and were stabilized by electrostatic interactions, as indicated by a negative ¿-potential of -60 to -80 mV. With these latexes, films were prepared at elevated temperatures. Two different crosslinkers were compared, i.e. 1,6-diaminohexane (DAH) and adipic acid dihydrazide (ADH). The latter was found to form irreversible crosslinks at lower temperatures than DAH. Furthermore, DAH decreased the stability of the polymer latexes, whereas addition of the dihydrazide based crosslinker left the properties of the latex unchanged. Only upon evaporation of the water and heating of the sample the network formation takes place, as was shown with atomic force microscopy. The films that were formed with these latexes and ADH, proved to be hydrophobic, as was indicated by the high advancing water contact angle, varying from 95 up to 105 °, depending on the type of latex that was used. The adhesion of the coatings to different substrates was investigated with pull-off tests, and showed that the coatings strongly adhered to the aluminum substrates. Only for the hydrophobic poly(octadecene-altmaleic anhydride) (POMA) a poor adhesion was found. Furthermore, the adhesion to magnesium alloys and steel appeared to be relatively poor, compared to aluminum. On films formed with the dihydrazide as crosslinker, anti-corrosion studies were performed, which were compared to a commercially available polyester based coating applied from solution. The barrier properties, as measured with electrochemical impedance spectroscopy, indicated good corrosion protection in a corrosive medium (5 wt% NaCl aqueous solution). For longer immersion times in this medium, hydrolytic degradation was observed for the polyester, while the latex based coatings did not degrade noticeable. The results obtained in this project show that within one polymer system the requirements of an anti-corrosion coating can be combined. The developed water-borne coatings show very promising properties for future anticorrosion applications.

For many years, people have been attracted by the self-cleaning property of the lotus leaf, and dream to develop man-made superhydrophobic surfaces. Many methods have been developed to produce a surface with a water contact angle higher than 150° and a low roll-off angle. In general, a superhydrophobic surface is prepared by combining high surface roughness and low surface energy. The challenge here is to develop a robust superhydrophobic surface with a simple process, so that it can be manufactured in an industrial scale and can be applied in our daily life. The aim of this PhD research is to develop a simple method to prepare a robust superhydrophobic surface. On the other hand, besides superhydrophobicity, oil repellency is also an attractive property which is essential to maintain self-cleaning property of a surface and has many potential applications. So another goal of this study is to investigate lipophobicity for superhydrophobic surfaces. In Chapter 2, we developed a polymeric film with very low surface energy through a self-stratification process. In this Chapter, we stressed that a low contact angle hysteresis is the most important factor for a superhydrophobic surface, and the low contact angle hysteresis only exists when the water droplet is in the Cassie state. The surface reorganization may be one of the reasons for the high water contact angle hysteresis on the polyurethane films with surface rich in perfluoroalkyl side chains. By mimicking the lotus leaf structure, we developed a raspberry-approach to synthesize superhydrophobic coatings with a dual-size surface structure in Chapter 3. The film was prepared by depositing well-defined silica-based raspberry-like particles on an epoxy-based polymer matrix, followed by the surface modification with PDMS. On this superhydrophobic film, advancing water contact angle is about 165°, and the roll-off angle of a 10-µL water droplet is about 2°. In addition, the size ratio between large and small particles of raspberry particles does not have a significant effect on the film wettability when it is larger than 10. The effect of the dual-size roughness on the surface wettability has also been studied by a free-energy modeling. In Chapter 4, a layer-by-layer (LbL) approach was developed to prepare a superhydrophobic surface, with the aim of improving the mechanical robustness of the film. Epoxy-based films were partially cured to a proper extent, followed by deposition of silica microparticles. After that, the films were completely cured. Subsequently, silica nanoparticles were grafted on the microparticle surface through amine-epoxy reactions. Finally, the surfaces were modified with a layer of PDMS to obtain their superhydrophobicity. To further increase the mechanical robustness of the films, the films were treated with SiCl4, which cross-linked the nano-and microparticles, and among nanoparticles. The films were then modified with a perfluoroalkylsilane to obtain superhydrophobicity. The partial embedment of the large silica particles in the polymer matrix and the cross-linking between large and small particles by SiCl4 have proven to be sufficient to obtain mechanically robust superhydrophobic surfaces. Lipophobicity on superhydrophobic surfaces was studied in Chapter 5. In this Chapter, we examine the lipophobicity on the superhydrophobic films with dual-size surface roughness. A surface with a dual-size roughness structure was modified with 1H,1H,2H,2H-perfluorodecyltrichlorosilane. Probe liquids with surface tensions ranging from 22.5 to 73 mN/m were prepared by mixing water and ethanol, and the contact angles of these probe liquids on the superhyphobic surface were examined. The contact angle results on such a surface are in a good agreement with the free-energy modeling study. On this surface, the contact angles of hexadecane, sunflower and oleic acid were 125°, 132° and 135°, respectively, indicating that the superhydrophobic surface is also lipophobic. However, this oil-repellent surface is still far from ideal due to the high oil roll-off angle. As an example of practical applications, a process of developing superhydrophobic textiles is described in Chapter 6. By in-situ growing silica microparticles to hydrophilic cotton textiles and using a hydrophobization (PDMS) step, the cotton textiles have been turned completely water non-wettable. Moreover, a superlipophobic textile was prepared by modifying the microparticle-covered cotton textiles with a perfluoroalkylsilane; the textile was then effectively turned superlipophobic.