A discussion of switching in polyvinyl difluoride copolymers is given (see L. Zhang, EPL 2010, 91, 47001) in terms of the general history of ferroelectric switching with and without domain wall participation.

such structures exist under ambient conditions and in total, only a few dozen 2D crystals have been successfully synthesized or exfoliated. While the unusual properties of graphene make it an interesting object of investigation itself, [1] it can also serve as a substrate to stabilize other, less obvious 2D materials. These include materials that do not by themselves form 2D phases, such as the covalent SiO 2 , [2] pseudo-ionic PbI 2 , [3] and metallic CuAu. [4] In the same spirit, layers of graphene have also been used to encapsulate materials. Metal atoms (in some cases forming nitrides [5,6] ) have been intercalated between a monocrystalline SiC surface and graphene to produce 2D metamaterials. [7][8][9] In other studies the encapsulation strategy has been applied in in situ transmission electron microscopy (TEM) observations of dynamics in liquids [10,11] and for protection of electron-beam-sensitive materials. [12,13] In addition, the inert and impermeable graphene envelope can also stabilize 2D layers of weakly bound molecules and atoms, and islands of C 60 fullerenes [14] and noble gases [15] have been Heterostructures composed of 2D materials are already opening many new possibilities in such fields of technology as electronics and magnonics, but far more could be achieved if the number and diversity of 2D materials were increased. So far, only a few dozen 2D crystals have been extracted from materials that exhibit a layered phase in ambient conditions, omitting entirely the large number of layered materials that may exist at other temperatures and pressures. This work demonstrates how such structures can be stabilized in 2D van der Waals (vdw) stacks under room temperature via growing them directly in graphene encapsulation by using graphene oxide as the template material. Specifically, an ambient stable 2D structure of copper and iodine, a material that normally only occurs in layered form at elevated temperatures between 645 and 675 K, is produced. The results establish a simple route to the production of more exotic phases of materials that would otherwise be difficult or impossible to stabilize for experiments in ambient.The ORCID identification number(s) for the author(s) of this article can be found under

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The microenvironment of cells in vivo is defined by spatiotemporal patterns of chemical and biophysical cues. Therefore, one important goal of tissue engineering is the generation of scaffolds with defined biofunctionalization in order to control processes like cell adhesion and differentiation. Mimicking extrinsic factors like integrin ligands presented by the extracellular matrix is one of the key elements to study cellular adhesion on biocompatible scaffolds. By using special thermoformable polymer films with anchored biomolecules micro structured scaffolds, e.g. curved and µ-patterned substrates, can be fabricated. Here, we present a novel strategy for the fabrication of µ-patterned scaffolds based on the “Substrate Modification and Replication by Thermoforming” (SMART) technology: The surface of a poly lactic acid membrane, having a low forming temperature of 60°C and being initially very cell attractive, was coated with a photopatterned layer of poly(L-lysine) (PLL) and hyaluronic acid (VAHyal) to gain spatial control over cell adhesion. Subsequently, this modified polymer membrane was thermoformed to create an array of spherical microcavities with diameters of 300 µm for 3D cell culture. Human hepatoma cells (HepG2) and mouse fibroblasts (L929) were used to demonstrate guided cell adhesion. HepG2 cells adhered and aggregated exclusively within these cavities without attaching to the passivated surfaces between the cavities. Also L929 cells adhering very strongly on the pristine substrate polymer were effectively patterned by the cell repellent properties of the hyaluronic acid based hydrogel. This is the first time cell adhesion was controlled by patterned functionalization of a polymeric substrate with UV curable PLL-VAHyal in thermoformed 3D microstructures.

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