Jens Höpken

Synthesis and Polymerization of Carbamate-Linked Cyclodextrin Methacrylate Monomers

Abstract A one-step synthesis for cyclodextrin methacrylate monomers was examined starting from α-, β- and γ-cyclodextrin. The reaction of 2-isocyanatoethyl methacrylate as well as allylisocyanate with the corresponding cyclodextrin gave the monofunctionalized carbamate-linked cyclodextrin methacrylates 2, 6 and 9 and allylcarbamates 11 and 14 in moderate yields. By NMR spectroscopic means, it could be proven that in all cases only the primary 6-hydroxyl groups of the cyclodextrins reacted with the isocyanate group. For the synthesis of a β-cyclodextrin monoallyl compound, a substitution reaction of purchasable 6-O-monotoluenesulfonyl-β-cyclodextrin with allylamine gave 6-N-allylamino-6-deoxy-β-cyclodextrin 18 in high yield. The reaction of 2-isocyanatoethyl methacrylate with α-cyclodextrin to the 6-O-carbamoyl-2-methylpropenoylethyl-α-cyclodextrin (2) was optimized so that the monomer 2 could be prepared on a larger scale without chromatographic separation. The aqueous radical homopolymerization of 2 wit...

Molecular Organization of Polystyrene and Polymethylmethacrylate with Fluorocarbon Side Chains

Polystyrene and polymethylmethacrylate with perfluoroalkyl side chains, F(CF2)n(СН2)m have been prepared and studied with respect to structure formation and utilization for oil and water repellent coatings. As the length of the side chains exceeds n=4 and m=2, the polymers crystallize in bilayers which itself form a multilayered structure. Solution casting yielded spontaneous assembling of the bilayers parallel to the substrate plane and gave laminate coatings. Very low critical surface tension values were determined by dynamic contact angle measurements. IR absorption and X-ray photoelectron spectroscopy revealed a highly ordered layer of fluorocarbon segments at the air/polymer interface. This is consistent with scanning force microscopy measurements showing a surface formed by regularly packed CF3-groups. Anisotropic variations of the linear spacing in directions parallel and perpendicular to the layers were detected by X-ray diffraction measurements at elevated temperatures and upon a glass transition.