and solvent induced liquid crystalline behavior of these substances was investigated by polarized optical microscopy, differential scanning calorimetry and X‐ray diffraction. Thereby the influence of the terminal groups attached to the tri(oxylethylene) moities as well as the influence of the length and the number of the alkyl chains on the mesophasebehavior were investigated. The single alkyl chain
Bent-core mesogens with thiophene and 2,2′-bithiophene units at the periphery of the aromatic core were synthesized and investigated by polarizing microscopy, XRD and electrooptical methods. Resorcinol, 2,7-naphthalenediol and 3,4′-biphenyldiol were used as bent units, phenyl thiophene-2-carboxylates form the rod-like wings and n-alkyl chains as well as olefin- and silylated-terminated alkyl chains were attached as flexible end-groups. A broad variety of different mesophase structures, incorporating ferroelectric and antiferroelectric switching smectic as well as modulated smectic phases, was obtained. Compared with the corresponding benzoates, these thiophene derived compounds form nearly identical LC phase structures, but have significantly reduced transition temperatures, which make them advantageous for applications.
The present invention relates to a process for the preparation of polyether polyols by the reaction of alkylene oxides and compounds containing active hydrogens, in the presence of specific Lewis acid metal compounds as catalysts, novel bis(perfluoroalkylsulfonic acid) compounds of Group 13 of the Periodic Table of the Elements, and to a process for the preparation thereof and the use thereof as catalysts for ring-opening polymerization of cyclic ethers.
Synthesis and Surface Functionalization of Particles
申请人:Board of Trustees of The University of Alabama
公开号:US20140179941A1
公开(公告)日:2014-06-26
Provided are methods of controlling the shape and surface chemistry of nanoparticles, particularly ferrite nanoparticles. Methods for preparing non-spherical ferrite nanoparticles, including nanocubes, nanobars, nanoplates, and nanoflowers, are described. Also provided are methods of functionalizing the surface of metal and metal oxide particles. The surface functionalization methods do not require the use of chemical linkers and/or additional reagents, and permit the facile conjugation of a range of molecules, including bioactive agents, to the surface of particles.
Modified macromolecular compounds obtainable by using specific amino silane polymerization initiator compounds and optionally chain end-modifying compounds are described. Polymer compositions including such modified macromolecular compounds and the use of such compositions in the preparation of vulcanized (crosslinked) elastomeric polymer compositions and articles are described.