Three hydrogen-bonded oligo(p-phenylenevinylene)s, OPV3, OPV4, and OPV5, that differ in conjugation length have been synthesized and fully characterized. All three compounds contain chiral side chains, long aliphatic chains, and a ureido-s-triazine hydrogen bonding unit. (1)H NMR and photophysical measurements show that the OPV oligomers grow hierarchically in an apolar solvent; initially, dimers are formed by hydrogen bonds that subsequently develop into stacks by pi-pi interactions of the phenylenevinylene backbone with induced helicity via the chiral side chains. SANS measurements show that rigid cylindrical objects are formed. Stacks of OPV4 have a persistence length of 150 nm and a diameter of 6 nm. OPV3 shows rigid columnar domains of 60 nm with a diameter of 5 nm. Temperature and concentration variable measurements show that the stability of the stacks increases with the conjugation length as a result of more favorable pi-pi interactions. The transfer of the single cylinders from solution to a solid support as isolated objects is only possible when specific concentrations and specific solid supports are used as investigated by AFM. At higher concentrations, an intertwined network is formed, while, at low concentration, ill-defined globular objects are observed. Only in the case of inert substrates (graphite and silicium oxide) single fibers are visible. In the case of the repulsive surfaces (mica and glass), clustering of the stacks occurs, while, at attractive surfaces (gold), the stacks are destroyed.

Block copoly(ether urea)s with uniform hard blocks consisting of two urea groups possess appealing elastomeric properties. The crystal structure of a model bisurea illustrates the formation of long stacks of hydrogenbonded urea groups. Thermal analysis of these polymers demonstrates the reversible melting of the hard blocks, causing the material to flow. The low glass transition temperature ensures excellent low-temperature flexibility. The morphology of the material consists of long stacks of associated hard blocks embedded in the soft phase. Elongation of the materials demonstrates their highly elastic behavior, with a strain at break ranging from 1000 to 2100%. During tensile testing, irreversible deformation and reorganization of the hard blocks occur, resulting in a significant amount of tensile set. These well-defined polymers proved to be superior compared to a lessdefined analogue having a polydisperse hard block.

A combination of DSC, SAXS, WAXD, 1H time-domain, and frequency domain NMR measurements was used for determining the amount of rigid/crystallinity, semirigid, and soft fractions of iPP. Changes in the rigid, semirigid, and soft fractions of isotactic polypropylene (iPP) were investigated as a function of temperature, annealing time, and annealing temperature. The most probable iPP morphology was established by TEM and by comparing 1H spin-diffusion data with data from multidimensional solutions of the spin-diffusion equations. Proton NMR spin-diffusion method, which employs double-quantum (DQ) and Goldman−Shen dipolar filters, was used in order to provide the domain thickness in iPP. The temperature dependence of spin diffusivities was taken into account, and a semiquantitative theory is presented for this dependence in the case of amorphous domains. A combination of 1H spin-diffusion NMR and SAXS was used to estimate the lamellar thicknesses for nonannealed and annealed iPP samples. Annealing at temperatures above 110 °C causes increases in the lamellar thickness and the crystallinity and a decrease in the chain mobility of rigid and semirigid fractions. The above quantities and the chain dynamics are reported for three annealing temperatures, 134, 143, and 153 °C, and an annealing time in the range of 15 min to 30 h. It is shown that the crystalline domains thickening during annealing of iPP can be described by a model based on irreversible thermodynamics. A phenomenological correlation is established between 1H transverse magnetization relaxation rate of the rigid fraction of iPP and the annealing temperatures.

Small‐angle X‐ray scattering measurements and UV/Vis titrations have been used to characterize a new water‐soluble host – guest system based on oligoethyleneoxy‐modified poly(propyleneimine) dendrimers. These experiments indicate that unique interactions between the host and guests lead to a specific location of the guests in the core of the dendrimers (see schematic representation).

A methodology for estimating the entanglement density in the amorphous phase of semicrystalline polyolefins was developed. The method is based on the analysis of the density of physical network junctions in the amorphous phase by 1 H NMR T 2 relaxation experiments. The density of the entanglement network was estimated for melt-and high-pressure-crystallized highdensity polyethylenes (HDPEs) at temperatures close to and gradually approaching melting. Its value is lower for high-pressure-crystallized HDPE than for the same melt-crystallized polymer. The network of entanglements is characterized by the fraction of entangled network chains, the weight-average molecular weight of the network chains between apparent chain entanglements, M e , and the volume average density of apparent chain entanglements. The entanglement network was studied in a series of low-and high-molecular-weight HDPEs and bimodal HDPE samples with different molecular weight characteristics and densities controlled by different contents of the 1-butene comonomer. It turns out that the molecular weight characteristics of the HDPEs influence the entanglement network. The fraction of network chains and the average density of apparent chain entanglements decrease with decreasing molecular weight M n due to the "dilution" effect caused by disentangled chain-end segments increasing the M e . The current methodology is of interest for studying the effect of crystallization conditions, molecular structures, and short-chain branches on phase composition, melting behavior, and chain entanglements in the amorphous phase of polyolefins. The method allows estimation of the fraction of network chains, which potentially can form tie-chain segments during deformation. The effect of short-chain branches and molecular weight characteristics on the creep response of polyolefins is discussed.