Shape Changes of Statistical Copolymacromonomers:  From Wormlike Cylinders to Horseshoe- and Meanderlike Structures

Amphiphile Blockcopolymere mit einem flexiblen Block und einem kettensteifen Segment aus“zylindrischen Bürstenpolymeren”: metallocenkatalysierte Synthese und Bildung von Riesenmicellen

The silicatein propeptide acts as inhibitor/modulator of self-organization during spicule axial filament formation.

Silicateins are crucial enzymes that are involved in formation of the inorganic biosilica scaffold of the spicular skeleton of siliceous sponges. We show that silicatein acquires its structure-guiding and enzymatically active state by processing of silicatein from pro-silicatein to the mature enzyme. A recombinant propeptide (PROP) of silicatein from the siliceous demosponge Suberites domuncula was prepared, and antibodies were raised against the peptide. In sponge tissue, these antibodies reacted with both surface structures and the central region of the spicules. Using phage display expression, spicule-binding 12-mer peptides were identified that are rich in histidine residues. In the pre…

Helix–Coil Transition in Cylindrical Brush Polymers with Poly-l-lysine Side Chains

Cylindrical brush polymers with poly-l-lysine side chains were prepared by grafting lysine NCA from a macroinitiator via living ring-opening polymerization. The main chain degree of polymerization of the methacrylate main chain was Pw = 870, the side chains consisted of 25 and 55 lysine repeat units, respectively. Upon deprotection, the cylindrical brush polymers in 0.005 M NaBr exhibited an almost rodlike conformation with a Kuhn statistical segment length of several hundred nanometers. Cryo-TEM as well as AFM in aqueous solution clearly demonstrated pronounced undulations along the main chain at low ionic strength which could not be detected at higher salt concentrations. With increasing …

Polymer Complexes in Biological Applications

This chapter summarizes the influence of polyelectrolyte topology on biological functions and biomedical applications such as cell uptake, drug delivery, and gene transfection. Polyelectrolytes utilized are spherical structures derived from dendrimers and albumin or cylindrical brushes, all of which are decorated with various polypeptide chains.

Micelle Formation from Amphiphilic“Cylindrical Brush”—Coil Block Copolymers Prepared by Metallocene Catalysis

Cluster formation and rheology of photoreactive nanoparticle dispersions.

We show how photocrosslinking of small nanoparticles within a very dilute colloidal dispersion leads to the formation of large fractal particle clusters, which have a strong influence on the viscosity of the dispersion although the overall solid content is well below 5 wt %. Furthermore, the solvent plays an important role because of its function as an optical filter, for example, in toluene only photocrosslinking but no photocleavage takes place. Therefore, a diffusion-controlled cluster growth mechanism, leading to clusters with low fractal dimension, is expected; on the other hand, in tetrahydrofuran the photoreaction is partially reversible. Therefore, the cluster growth in this case is…

Collapse of Cylindrical Brushes with 2-Isopropyloxazoline Side Chains Close to the Phase Boundary

A high-molar-mass cylindrical brush polymer with a main chain degree of polymerization of Pw = 1047 is synthesized by free-radical polymerization of a poly-2-isopropyloxazoline macromonomer with Pn = 28. The polymerization is conducted above the lower phase transition temperature of the macromonomer, i.e., in the phase-separated regime, which provides a sufficiently concentrated macromonomer phase mandatory to obtain high-molar-mass cylindrical brushes. Upon heating to the phase transition temperature, the hydrodynamic radius is observed to shrink from 34 to 27 nm. Further increase in temperature resulted in aggregated chains which were observed to coexist with single chains until eventuall…