TY - JOUR A1 - Angelova, Angelina A1 - Reiche, Jürgen A1 - Ionov, Radoslav A1 - Janietz, Dietmar A1 - Lemmetyinen, Helge A1 - Brehmer, Ludwig T1 - Control of the structure of Langmuir-Blodgett films of a discotic liquid crystalline compound via the subphase composition and the adjacent molecular environment N2 - Changes of the molecular arrangenemt that can be induced by means of the LB technique in the multilayers of a disc-shaped multialkynyl amphiphile are monitored by means of small angle X-ray diffraction. Studies of the monolayers at the air-water interface reveal "edge-on" orientation of the discs. Specific effects of the counter- ions (Na+, Cd²+, Pb²+, and Ba²+) and sub-solution pH on the monolayer collapse pressure, transfer efficiency and molecular order in the multilayers are found. A correlation between the monolayer properties and the ability for formation of periodic discotic structures in the presence of divalent counterions is established. The discotic molecules retain their "edge-on" arrangement in the highly compressed transferred films with slight irregular interdigtation of the flexible wings and inclination to the substrate normal. The tilt and the inter- digitation are reduced when the discotic monolayers are deposited in alternating LB films with barium arachidate spacer layers. Y1 - 1994 ER - TY - JOUR A1 - Festag, R. A1 - Schmidt, C. A1 - Wendorff, Joachim Heinz A1 - Janietz, Dietmar T1 - Structure and dynamics of new triazine based polymers with discotic side groups Y1 - 1995 ER - TY - JOUR A1 - Frübing, Peter A1 - Grasnick, G. A1 - Herkner, G. A1 - Janietz, Dietmar A1 - Brehmer, Ludwig T1 - Pyroelektrische Untersuchungen an Polyvinylalkoholen mit Azobenzen / Alkoxy - Seitenketten Y1 - 1995 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Dietel, Reinhard A1 - Janietz, Dietmar A1 - Schmidt, C. A1 - Wendorff, Joachim Heinz T1 - Sheet-shaped mesogens based on 1,3,5-Triazines : variation of columnar mesophases through intermolecular hydrogen bonding Y1 - 1998 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Janietz, Dietmar A1 - Schmidt, C. A1 - Wendorff, Joachim Heinz T1 - Columnar liquid crystalline phases through hydrogen bonding and nanoscale segregation N2 - Two columnar phases forming 2,4,6-triarylamino-1,3,5-triazines have been investigated in binary mixtures with calamitic and non-liquid crystalline benzoic acids carrying one or two alkoxy chains at the aromatic core. The triazines form hydrogen bonded aggregates with the complementary acids. Each investigated equimolar mixture exhibits a columnar mesophase due to segregation of the H-bonded polar core region from the lipophilic aliphatic molecular segments. The cross sectional shape of cylindrical aggregates and, therefore, the two-dimensional lattice symmetries, hexagonal or rectangular, are defined by the number of alkoxy chains of the benzoic acid component Y1 - 2004 SN - 0959-9428 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Janietz, Dietmar A1 - Schmidt, C. A1 - Wendorff, Joachim Heinz T1 - Liquid crystalline 1,3,5-triazines incorporating rod-like azobenzene sub-units Y1 - 1998 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Janietz, Dietmar A1 - Schmidt, C. A1 - Wendorff, Joachim Heinz T1 - Disc-shaped mesogens based on 1,3,5-triazines : variation and induction of columnar mesophases through complementary intermolecular interactions Y1 - 1996 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Mahlstedt, S. A1 - Janietz, Dietmar A1 - Busch, P. A1 - Schmidt, C. A1 - Stracke, A. A1 - Wendorff, Joachim Heinz T1 - Mesomorphic donor-acceptor twin molecules with covalently linked sheet-like pentaalkyne and nitrofluorenone subunits Y1 - 1998 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Nordsieck, A. A1 - Janietz, Dietmar A1 - Frese, T. A1 - Schmidt, C. A1 - Wendorff, Joachim Heinz T1 - Smectic and columnar liquid crystalline phases through charge-transfer interactions N2 - New heterocyclic electron donors based on. a 1,3,5-triazine nucleus are presented. Three phenyl rings are grafted to the triazine core either via secondary amino groups or by a direct C,C-linkage and a specific number of decyloxy chains is attached to the molecular periphery. The compounds are non-liquid crystalline in their pure states. Lamellar or columnar mesophases are induced by attractive interactions with electron acceptors Y1 - 2004 SN - 1058-725X ER - TY - JOUR A1 - Inal, Sahika A1 - Koelsch, Jonas D. A1 - Chiappisi, Leonardo A1 - Janietz, Dietmar A1 - Gradzielski, Michael A1 - Laschewsky, André A1 - Neher, Dieter T1 - Structure-related differences in the temperature-regulated fluorescence response of LCST type polymers JF - Journal of materials chemistry : C, Materials for optical and electronic devices N2 - We demonstrate new fluorophore-labelled materials based on acrylamide and on oligo(ethylene glycol) (OEG) bearing thermoresponsive polymers for sensing purposes and investigate their thermally induced solubility transitions. It is found that the emission properties of the polarity-sensitive (solvatochromic) naphthalimide derivative attached to three different thermoresponsive polymers are highly specific to the exact chemical structure of the macromolecule. While the dye emits very weakly below the LCST when incorporated into poly(N-isopropylacrylamide) (pNIPAm) or into a polyacrylate backbone bearing only short OEG side chains, it is strongly emissive in polymethacrylates with longer OEG side chains. Heating of the aqueous solutions above their cloud point provokes an abrupt increase of the fluorescence intensity of the labelled pNIPAm, whereas the emission properties of the dye are rather unaffected as OEG-based polyacrylates and methacrylates undergo phase transition. Correlated with laser light scattering studies, these findings are ascribed to the different degrees of pre-aggregation of the chains at low temperatures and to the extent of dehydration that the phase transition evokes. It is concluded that although the temperature-triggered changes in the macroscopic absorption characteristics, related to large-scale alterations of the polymer chain conformation and aggregation, are well detectable and similar for these LCST-type polymers, the micro-environment provided to the dye within each polymer network differs substantially. Considering sensing applications, this finding is of great importance since the temperature-regulated fluorescence response of the polymer depends more on the macromolecular architecture than the type of reporter fluorophore. Y1 - 2013 U6 - https://doi.org/10.1039/c3tc31304b SN - 2050-7526 VL - 1 IS - 40 SP - 6603 EP - 6612 PB - Royal Society of Chemistry CY - Cambridge ER -