The synthesis and the characterization of a poly(2-methyloxazoline)-block-poly(dimethylsiloxane)-blockpoly(2-methyloxazoline) (PMOXA-PDMS-PMOXA) triblock copolymer carrying polymerizable groups at both chain ends are described. This copolymer forms vesicular structures in dilute aqueous solution, the size of which can be controlled in the range from 50 nm up to about 500 nm. The methacrylate end groups of the triblock copolymer can be polymerized in the vesicular aggregates using an UV-induced free radical polymerization. Static and dynamic light scattering, scanning electron microscopy, and transmission electron microscopy on both the resulting nanocapsules and their nonpolymerized precursors clearly show that the cross-linking polymerization does not lead to morphological changes in the underlying vesicles. Moreover, due to their cross-linked structure, the nanocapsules are shape persistent, thus maintaining their integrity even after their isolation from the aqueous solution.

A new kind of nanoreactor has been prepared by the incorporation of a channel protein into the shell of (polymerized) vesicles formed from an amphiphilic ABA-triblock copolymer.

Self-assembly of an amphiphilic triblock copolymer carrying polymerizable end-groups is used to prepare nanometer-sized vesicular structures in aqueous solution. The triblock copolymer shells of the vesicles can be regarded as a mimetic of biological membranes although they are 2 to 3 times thicker than a conventional lipid bilayer. Nevertheless, they can serve as a matrix for membrane-spanning proteins. Surprisingly, the proteins remain functional despite the extreme thickness of the membranes and that even after polymerization of the reactive triblock copolymers. This opens a new field to create mechanically stable protein/polymer hybrid membranes. As a representative example we functionalize (polymerized) triblock copolymer vesicles by reconstituting a channel-forming protein from the outer cell wall of Gramnegative bacteria. The protein used (OmpF) acts as a size-selective filter, which allows only for passage of molecules with a molecular weight below 400 g mol −1 . Therefore substrates may still have access to enzymes encapsulated in such protein/polymer hybrid nanocontainers. We demonstrate this using the enzyme β-lactamase which is able to hydrolyze the antibiotic ampicillin. In addition, a transmembrane voltage above a given threshold causes a reversible gating transition of OmpF. This can be used to reversibly activate or deactivate the resulting nanoreactors.

For the first time giant free-standing monomolecular films of a functionalized poly(2-methyloxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyloxazoline), PMOXA−PDMS−PMOXA, triblock copolymer were prepared. Stable films with areas up to about 1 mm2 and thickness of 10 nm were achieved. This triblock copolymer carries polymerizable methacrylate groups at both chain ends. These end groups could be polymerized by UV light after the formation of the self-assembled structure. The mechanical properties of these films were characterized by applying short electric field pulses. In comparison to lipid bilayers, the polymer films were significantly more cohesive, seen by higher critical voltages required for rupture. Moreover, polymerization increased the stability significantly.

Positively charged layered double hydroxide particles composed of Mg(2+) and Al(3+) layer-forming cations and NO3(-) charge compensating anions (MgAl-NO3-LDH) were synthesized and the colloidal stability of their aqueous suspensions was investigated in the presence of inorganic anions of different charges. The formation of the layered structure was confirmed by X-ray diffraction, while the charging and aggregation properties were explored by electrophoresis and light scattering. The monovalent anions adsorb on the oppositely charged surface to a different extent according to their hydration state leading to the Cl(-) > NO3(-) > SCN(-) > HCO3(-) order in surface charge densities. The ions on the right side of the series induce the aggregation of MgAl-NO3-LDH particles at lower concentrations, whereas in the presence of the left ones, the suspensions are stable even at higher salt levels. The adsorption of multivalent anions gave rise to charge neutralization and charge reversal at appropriate concentrations. For some di, tri and tetravalent ions, charge reversal resulted in restabilization of the suspensions in the intermediate salt concentration regime. Stable samples were also observed at low salt levels. Particle aggregation was fast near the charge neutralization point and at high concentrations. These results, which evidence the colloidal stability of MgAl-NO3-LDH in the presence of various anions, are of prime fundamental interest. These are also critical for applications to develop stable suspensions of primary particles for water purification processes, with the aim of the removal of similar anions by ion exchange.

An ionophore assisted metal-ion transport across block copolymer membranes has been used to control the local Ca2+ concentration during precipitation of calcium phosphate in giant block copolymer vesicles.

A new class of mechanically stable block copolymer protein hybrid materials: Giant freestanding membranes with a thickness of 10 nm were prepared from polymerizable amphiphilic triblock copolymers in which, despite their extreme thickness, it was possible to reconstitute channel proteins. The proteins remained functional in the completely artificial surrounding even after polymerization of the membranes, as revealed by conductance measurements. These polymer–protein hybrid materials possess great potential for applications in the area of diagnostics, sensor technology, protein crystallization, and even drug delivery.

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