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Aluminum sheets were furnished with a water‐repellent composite layer consisting of microroughened alumina, chitosan (CHS), and poly[octadecene‐alt‐(maleic anhydride)] (POMA). CHS was electrochemically deposited or spin‐coated. In a subsequent reaction step, POMA was covalently bonded onto the immobilized CHS layer. The produced composite layers showed superhydrophobic properties, which are indicated by the water contact angles >150° and negligible hysteresis. Cross‐linking reactions of the CHS layer were able to enhance the layer stability. The superhydrophobic surface properties were also maintained after abrasion of the protruding polymer‐coated alumina peaks. This is due to a CHS/POMA reservoir incorporated in the microroughened alumina surface region.magnified image

X-ray photoelectron spectroscopy (XPS) was used to detect the bonding between a silica particle surface and attached silanes. In addition to the commonly recorded Si 2p spectrum, the Si 1 s level is also accessible when monochromatic Ag Lalpha X-rays are applied. Furthermore, the spectrum of the Si 1 s level shows a fine structure. After spectrum deconvolution, we assigned the fitted spectral peaks to Si-C bonds of the silanes and to the Si-O bonds of the silica network. The recorded Si 1 s spectra were deconvoluted into peaks originating from Si-C bonds and the Si-O-Si silica network. To check the results of spectrum deconvolution, several differently functionalized silanes containing stoichiometric amounts of heteroatoms were applied for silica surface modification. We conclude that spectra deconvolution of the Si 1 s signal is an appropriate means for quantification of surface attached silane molecules.

Hydrophobically modified chitosan microparticles were produced by various syntheses carried out as heterogeneous phase reactions. Perfluorinated carbonyl components such as carbonic acids and acid chlorides were used as hydrophobization agents. To enhance the layer stability preceding cross-linkages between the chitosan macromolecules were introduced. These cross-linkages involve some of the chitosan amino groups. The use of a highly reactive alkylene-maleic anhydride copolymer produces cross-linkages and hydrophobizes the chitosan layer simultaneously in a one-step reaction. The heterogeneous reactions serve as model reactions for the hydrophobization of chitosan films deposited on supports.