Eindhoven University of Technology

About: Eindhoven University of Technology is a education organization based out in Eindhoven, Noord-Brabant, Netherlands. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 22309 authors who have published 52936 publications receiving 1584164 citations. The organization is also known as: Technische Hogeschool Eindhoven & TU/e.

White-light emitting hydrogen-bonded supramolecular copolymers based on π-conjugated oligomers

Abstract: Three different pi-conjugated oligomers (a blue-emitting oligofluorene, a green-emitting oligo(phenylene vinylene), and a red-emitting perylene bisimide) have been functionalized with self-complementary quadruple hydrogen bonding ureidopyrimidinone (UPy) units at both ends. The molecules self-assemble in solution and in the bulk, forming supramolecular polymers. When mixed together in solution, random noncovalent copolymers are formed that contain all three types of chromophores, resulting in energy transfer upon excitation of the oligofluorene energy donor. At a certain mixing ratio, a white emissive supramolecular polymer can be created in solution. In contrast to their unfunctionalized counterparts, bis-UPy-chromophores can easily be deposited as smooth thin films on surfaces by spin coating. No phase separation is observed in these films, and energy transfer is much more efficient than in solution, giving rise to white fluorescence at much lower ratios of energy acceptor to donor. Light emitting diodes based on these supramolecular polymers have been prepared from all three types of pure materials, yielding blue, green, and red devices, respectively. At appropriate mixing ratios of these three compounds, white electroluminescence is observed. This approach yields a toolbox of molecules that can be easily used to construct pi-conjugated supramolecular polymers with a variety of compositions, high solution viscosities, and tuneable emission colors.

Chemical modification of self-assembled silane based monolayers by surface reactions

Abstract: In this critical review, we look at how the functionalization of solid substrates by self-assembly processes provides the possibility to tailor their surface properties in a controllable fashion. One class of molecules, which attracted significant attention during the past decades, are silanes self-assembled on hydroxyl terminated substrates, e.g. silicon and glass. These systems are physically and chemically robust and can be applied in various fields of technology, e.g., electronics, sensors, and others. The introduction of chemical functionalities in such monolayers can be generally obtained via two methods. This involves either the use of pre-functionalized molecules, which can be synthesized by different synthetic routes and subsequent self-assembly of these moieties on the surface. The second method utilizes chemical surface reactions for the modification of the monolayer. The latter method offers the possibility to apply a large variety of different organic reaction pathways on surfaces, which allows the introduction of a wide range of terminal end groups on well-defined base monolayers. In contrast to the first approach an important advantage is that the optimization of the reaction conditions for suitable precursor molecules is circumvented. The following review highlights a selection of chemical surface reactions, i.e., nucleophilic substitution, click chemistry and supramolecular modification, which have been used for the functionalization of solid substrates (80 references).

Preparation of Conductive Nanotube–Polymer Composites Using Latex Technology

Abstract: Composites consisting of individual, or bundles of single-walled, exfoliated nanotubes in a highly viscous polymer matrix (see Figure) are described. The nanotubes and polymer are made compatible using surfactant molecules, hence avoiding the need for direct attraction between the nanotubes and the matrix. The resulting nanotube-polymer composites have a conductivity percolation threshold of 0.28 wt.-% nanotubes.