The average magnetic anisotropy of polystyrene in polymersomes self-assembled from poly(ethylene glycol)--polystyrene.

Using the diamagnetic anisotropy of polymers for the characterization of polymers and polymer aggregates is a relatively new approach in the field of soft-matter and polymer research. So far, a good and thorough quantitative description of these diamagnetic properties has been lacking. Using a simple equation that links the magnetic properties of an average polymer repeating unit to those of the polymer vesicle of any shape, we measured, using magnetic birefringence, the average diamagnetic anisotropy of a polystyrene (PS) repeating unit, Δ, inside a poly(ethylene glycol)-polystyrene (PEG-PS) polymersome membrane as a function of the PS-length and as a function of the preparation method.

Stomatocyte in Stomatocyte: A New Shape of Polymersome Induced via Chemical-Addition Methodology.

Accurate control of the shape transformation of polymersome is an important and interesting challenge that spans across disciplines such as nanomedicine and nanomachine. Here, we report a fast and facile methodology of shape manipulation of polymersome via out-of-equilibrium polymer self-assembly and shape change by chemical addition of additives. Due to its increased permeability, hydrophilicity, and fusogenic properties, poly(ethylene oxide) was selected as the additive for bringing the system out of equilibrium via fast addition into the polymersome organic solution.

Formation of Well-Defined, Functional Nanotubes via Osmotically Induced Shape Transformation of Biodegradable Polymersomes.

Polymersomes are robust, versatile nanostructures that can be tailored by varying the chemical structure of copolymeric building blocks, giving control over their size, shape, surface chemistry, and membrane permeability. In particular, the generation of nonspherical nanostructures has attracted much attention recently, as it has been demonstrated that shape affects function in a biomedical context. Until now, nonspherical polymersomes have only been constructed from nondegradable building blocks, hampering a detailed investigation of shape effects in nanomedicine for this category of nanostructures.

Manipulation of micro- and nanostructure motion with magnetic fields.

In this review we will focus on how magnetic fields can be used to manipulate the motion of various micro- and nanostructures in solution. We will distinguish between ferromagnetic, paramagnetic and diamagnetic materials. Furthermore, the use of various kinds of magnetic fields, such as homogeneous, inhomogeneous and rotating magnetic fields, is discussed.

Probing morphological changes in polymersomes with magnetic birefringence.

Magnetic birefringence was used for in situ monitoring of the morphological changes in diamagnetic polymersomes during shape-transformation by dialysis. The birefringence was found to be very sensitive to the polymersome morphology, as determined by electron microscopy. The deflation of polymersomes into disks was observed, followed by a bending and partial inflation into stomatocytes.