This work addresses the question of the scaling behavior of polyelectrolytes in solution for a realistic prototype. We show results of a combined experimental (light scattering) and theoretical (computer simulations) investigation of structural properties of the sodium salt of poly (acrylic acid) (Na-PAA). Experimentally, we determined the molecular weight (MW) and the hydrodynamic radius (RH) by static and dynamic light scattering for six different Na-PAA samples in aqueous NaCl-containing solution (0.1–1 mol/l) of polydispersity DP between 1.5 and 1.8. On the computational side, three different variants of a newly developed mesoscopic force field for Na-PAA were employed to determine RH for monodisperse systems of the same MW as in the experiments. The force field effectively incorporates atomistic information and one coarse-grained bead corresponds to one PAA monomer. We find that RH matches with the experimental data for all investigated samples. The effective scaling exponent for RH is found to be around 0.55, which is well below its asymptotic value for good solvents. Additionally, data for the radius of gyration (RG) are presented.

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Even though the semimetallic behavior of 1T-TiSe2 seemed to be well established by band structure calculations and photoemission results, this conclusion has been challenged recently. Two high-resolution photoemission investigations deduced semiconducting behavior, however with a very small band gap. Such conclusion from photoemission is afflicted, in principle, by the problem of determining an unoccupied conduction band by photoemission. This problem is solved here by the idea of H2O adsorption onto the van der Waals-like surface, causing a distinct bending of the bands and resulting in a filled lowest conduction band. The detailed analysis yields undoubtedly semiconducting behavior for 1T-TiSe2 and interesting properties of a semiconductor with extremely small band gap.

As a new family of semiconductors, graphene nanoribbons (GNRs), nanometer-wide strips of graphene, have appeared as promising candidates for next-generation nanoelectronics. Out-of-plane deformation of π-frames in GNRs brings further opportunities for optical and electronic property tuning. Here we demonstrate a novel fjord-edged GNR ( FGNR ) with a nonplanar geometry obtained by regioselective cyclodehydrogenation. Triphenanthro-fused teropyrene 1 and pentaphenanthro-fused quateropyrene 2 were synthesized as model compounds, and single-crystal X-ray analysis revealed their helically twisted conformations arising from the [5]helicene substructures. The structures and photophysical properties of FGNR were investigated by mass spectrometry and UV–vis, FT-IR, terahertz, and Raman spectroscopic analyses combined with theoretical calculations.

Results on thermodiffusion of poly͑ethylene oxide͒ and colloidal boehmite (␥-AlOOH͒ rods in ethanol/water mixtures are presented. Data were obtained using thermal diffusion forced Rayleigh scattering. The sign of the Soret coefficient of the boehmite rods changes from positive to negative with increasing water content, i.e., at sufficiently high water content the colloidal particles move to higher temperatures. The sign of the Soret coefficient of the poly͑ethylene oxide͒ in ethanol/water mixtures is negative, i.e., the poly͑ethylene oxide͒ molecules move to higher temperatures, whereas in pure water the sign is positive. To our knowledge this is the first time that a sign change has been observed for polymers in solution. The analysis of the static light scattering on poly͑ethylene oxide͒ allows the determination of the preferentially solvating solvent. In the investigated concentration range the preferentially solvating solvent is ethanol, in spite of being the poorer solvent for poly͑ethylene oxide͒.

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Lignin-based nano- and microcarriers are a promising biodegradable drug delivery platform inside of plants. Many wood-decaying fungi are capable of degrading the wood component lignin by segregated lignases. These fungi are responsible for severe financial damage in agriculture, and many of these plant diseases cannot be treated today. However, enzymatic degradation is also an attractive handle to achieve a controlled release of drugs from artificial lignin vehicles. Herein, chemically cross-linked lignin nanocarriers (NCs) were prepared by aza-Michael addition in miniemulsion, followed by solvent evaporation. The cross-linking of lignin was achieved with the bio-based amines (spermine and spermidine). Several fungicides—namely, azoxystrobin, pyraclostrobin, tebuconazole, and boscalid—were encapsulated in situ during the miniemulsion polymerization, demonstrating the versatility of the method. Lignin NCs with diameters of 200–300 nm (determined by dynamic light scattering) were obtained, with high encapsulation efficiencies (70–99%, depending on the drug solubility). Lignin NCs successfully inhibited the growth of Phaeomoniella chlamydospora and Phaeoacremonium minimum , which are lignase-producing fungi associated with the worldwide occurring fungal grapevine trunk disease Esca. In planta studies proved their efficiency for at least 4 years after a single injection into Vitis vinifera (“Portugieser”) plants on a test vineyard in Germany. The lignin NCs are of high interest as biodegradable delivery vehicles to be applied by trunk injection against the devastating fungal disease Esca but might also be promising against other fungal plant diseases.

A series of soluble low molecular weight poly(p-phenylene)s (PPP) has been synthesized by an excess polycondensation with the Suzuki coupling method. The reaction mixture therefore only contains oligomers of an odd number of phenylene units which are terminated by bromine atoms. The mixture has been preparatively separated into monodisperse fractions of the respective oligomers of up to 17 phenylene units. The absorption and emission spectra as well as the extinction coefficient of each fraction have been measured. On the basis of these data, the effective conjugation length can be estimated to be around 11 phenylene units. The fraction x i of each oligomer in the reaction mixture has been calculated and quantified by analytical HPLC and MALDI−TOF mass spectrometry. The theoretically expected exponential decay of the fraction sizes with increasing length is found in the HPLC analysis; however, significant deviations are found if analyzed by MALDI−TOF mass spectrometry. Possible reasons for this deviation will be discussed.